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Abstract: This corrigendum provides a new version of one of the 3 supplementary data files associated with the article A. Alkadrou et al., J. Quant. Spectrosc. Radiat. Transf. 182 (2016) 158–171, namely the HITRAN-formatted linelist generated as described in section 5 of the article. Indeed, the Ka and Kc labels of the upper levels of a number of transitions belonging to the ν10, ν7 and ν4 bands listed in this supplementary data file were found to be incorrect. The linelist provided with this corrigendum corrects these erroneous assignments, and provides Ka and Kc labels for all the upper levels. © 2017 Elsevier Ltd
BibTeX:
@article{Alkadrou2017,
  author = {Alkadrou, A. and Bourgeois, M.-T. and Rotger, M. and Boudon, V. and Vander Auwera, J.},
  title = {Corrigendum to “Global frequency and intensity analysis of the ν10/ν7/ν4/ν12 band system of 12C2H4 at 10 μm using the D2 h top data system” (Journal of Quantitative Spectroscopy and Radiative Transfer (2017) 190 (88) (S0022407315303162) (10.1016/j.jqsrt.2016.05.024))},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2017},
  volume = {190},
  pages = {88},
  doi = {10.1016/j.jqsrt.2017.01.007}
}
Abstract: Separating concentrations of carbon monoxide (CO) in the boundary layer from the rest of the atmosphere with nadir satellite measurements is of particular importance to differentiate emission from transport. Although thermal infrared (TIR) satellite sounders are considered to have limited sensitivity to the composition of the near-surface atmosphere, previous studies show that they can provide information on CO close to the ground in case of high thermal contrast. In this work we investigate the capability of IASI (Infrared Atmospheric Sounding Interferometer) to retrieve near-surface CO concentrations, and we quantitatively assess the influence of thermal contrast on such retrievals. We present a 3-part analysis, which relies on both theoretical forward simulations and retrievals on real data, performed for a large range of negative and positive thermal contrast situations. First, we derive theoretically the IASI detection threshold of CO enhancement in the boundary layer, and we assess its dependence on thermal contrast. Then, using the optimal estimation formalism, we quantify the role of thermal contrast on the error budget and information content of near-surface CO retrievals. We demonstrate that, contrary to what is usually accepted, large negative thermal contrast values (ground cooler than air) lead to a better decorrelation between CO concentrations in the low and the high troposphere than large positive thermal contrast (ground warmer than the air). In the last part of the paper we use Mexico City and Barrow as test cases to contrast our theoretical predictions with real retrievals, and to assess the accuracy of IASI surface CO retrievals through comparisons to ground-based in-situ measurements. © 2017 Elsevier Ltd
BibTeX:
@article{Bauduin2017,
  author = {Bauduin, S. and Clarisse, L. and Theunissen, M. and George, M. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {IASI's sensitivity to near-surface carbon monoxide (CO): Theoretical analyses and retrievals on test cases},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2017},
  volume = {189},
  pages = {428-440},
  doi = {10.1016/j.jqsrt.2016.12.022}
}
Abstract: A direct simulation Monte Carlo (DSMC) method is applied to model collisions between He buffer gas atoms and ammonia molecules within a buffer gas cell. State-to-state cross sections, calculated as a function of the collision energy, enable the inelastic collisions between He and NH3 to be considered explicitly. The inclusion of rotational-state-changing collisions affects the translational temperature of the beam, indicating that elastic and inelastic processes should not be considered in isolation. The properties of the cold molecular beam exiting the cell are examined as a function of the cell parameters and operating conditions; the rotational and translational energy distributions are in accord with experimental measurements. The DSMC calculations show that thermalisation occurs well within the typical 10-20 mm length of many buffer gas cells, suggesting that shorter cells could be employed in many instances - yielding a higher flux of cold molecules. © 2017 Author(s).
BibTeX:
@article{Doppelbauer2017,
  author = {Doppelbauer, M.J. and Schullian, O. and Loreau, J. and Vaeck, N. and Van Der Avoird, A. and Rennick, C.J. and Softley, T.P. and Heazlewood, B.R.},
  title = {Using a direct simulation Monte Carlo approach to model collisions in a buffer gas cell},
  journal = {Journal of Chemical Physics},
  year = {2017},
  volume = {146},
  article number = {044302},
  doi = {10.1063/1.4974253}
}
Abstract: The high resolution spectrum of 15NH3 has been recorded at unapodized resolution of 0.00096cm-1 in the region 60-600cm-1 using the Bruker IFS 125 Fourier transform spectrometer located at the far-infrared beam-line, Canadian Light Source. We report on the observation and analysis of the rotation-inversion spectrum in the ground, v2=1, 2 and v4=1 states. All the rotation-inversion transitions in the ground state together with the pure inversion transitions present in the literature were fitted simultaneously on the basis of a rotation-inversion Hamiltonian which includes distortion constants up to the 12th power in the angular momentum and the δk=±3 and δk=±6 interaction terms. A set of effective parameters was also obtained for the v2=1 state adopting the same theoretical model. For the v2=2 and v4=1 states only a list of observed transitions is reported. The wavenumbers of all the assigned transitions were compared with their theoretically predicted values [S.N. Yurchenko, J. Quant. Spectrosc. Radiat. Transf., 2015, 152, 28]. The present results noticeably improve the wavenumber line list in the HITRAN data base [L. S. Rothman et al. J. Quant. Spectrosc. Radiat. Transf.,2013, 130, 4]. © 2017 Elsevier Ltd.
BibTeX:
@article{Fusina2017,
  author = {Fusina, L. and Di Lonardo, G. and Canè, E. and Predoi-Cross, A. and Rozario, H. and Herman, M.},
  title = {The high resolution spectrum of 15NH3 in the far-infrared: Rotation-inversion transitions in the ground, v2=1, 2 and v4=1 states},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2017},
  doi = {10.1016/j.jqsrt.2017.01.021}
}
Abstract: Infrared transmission spectra of several molecular gases inside three porous silica samples with pore sizes ranging from 7 nm to several tens of nm have been recorded with a Fourier transform spectrometer. Their analysis shows that consistent values of the percentage of open porosity and average pore size can be retrieved from these non intrusive nor destructive optical measurements. The samples have also been characterized using mercury intrusion/extrusion and the nitrogen sorption method. The results of these different probing techniques are in good agreement when the methods used are adapted to the involved pore size. This consistency demonstrates that light absorption by confined gases is a valuable porosimetry tool. © 2016 Elsevier Inc.
BibTeX:
@article{Hartmann2017,
  author = {Hartmann, J.-M. and Vander Auwera, J. and Boulet, C. and Birot, M. and Dourges, M.-A. and Toupance, T. and El Hamzaoui, H. and Ausset, P. and Carré, Y. and Kocon, L. and Capoen, B. and Bouazaoui, M.},
  title = {Infrared absorption by molecular gases to probe porous materials and comparisons with other techniques},
  journal = {Microporous and Mesoporous Materials},
  year = {2017},
  volume = {237},
  pages = {31-37},
  doi = {10.1016/j.micromeso.2016.09.014}
}
Abstract: We present measurements of ion-pair dissociation (IPD) of highly excited neutral and ionized carbon clusters Cn=2-5(q=0-3)+. The tool for producing these species was a high-velocity collision between Cn+ projectiles (v=2.25 a.u.) and helium atoms. The setup allowed us to detect in coincidence anionic and cationic fragments, event by event, leading to a direct and unambiguous identification of the IPD process. Compared with dissociation without anion emission, we found typical 10-4 IPD rates, not depending much on the size and charge of the (n,q) species. Exceptions were observed for C2+ and, to a lesser extent, C43+ whose IPDs were notably lower. We tentatively interpret IPDs of C2+ and C3+ by using a statistical approach based on the counting of final states allowed by energetic criteria. The model is able to furnish the right order of magnitude for the experimental IPD rates and to provide a qualitative explanation of the lower IPD rate observed in C2+. © 2017 American Physical Society.
BibTeX:
@article{Launoy2017,
  author = {Launoy, T. and Béroff, K. and Chabot, M. and Martinet, G. and Le Padellec, A. and Pino, T. and Bouneau, S. and Vaeck, N. and Liévin, J. and Féraud, G. and Loreau, J. and Mahajan, T.},
  title = {Ion-pair dissociation of highly excited carbon clusters: Size and charge effects},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2017},
  volume = {95},
  article number = {022711},
  doi = {10.1103/PhysRevA.95.022711}
}
Abstract: Methane (CH4) and ammonia (NH3) directly and indirectly affect the atmospheric radiative balance with the latter leading to aerosol generation. Both have important spectral features in the Thermal InfraRed (TIR) that can be studied by remote sensing, with NH3 allowing discrimination of husbandry from other CH4 sources. Airborne hyperspectral imagery was collected for the Chino Dairy Complex in the Los Angeles Basin as well as in situ CH4, carbon dioxide (CO2) and NH3 data. TIR data showed good spatial agreement with in situ measurements and showed significant emissions heterogeneity between dairies. Airborne remote sensing mapped plume transport for ∼20 km downwind, documenting topographic effects on plume advection. Repeated multiple gas in situ measurements showed that emissions were persistent on half-year timescales. Inversion of one dairy plume found annual emissions of 4.1 × 105 kg CH4, 2.2 × 105 kg NH3, and 2.3 × 107 kg CO2, suggesting 2300, 4000, and 2100 head of cattle, respectively, and Chino Dairy Complex emissions of 42 Gg CH4 and 8.4 Gg NH3 implying ∼200k cows, ∼30% more than Peischl et al. (2013) estimated for June 2010. Far-field data showed chemical conversion and/or deposition of Chino NH3 occurs within the confines of the Los Angeles Basin on a four to six h timescale, faster than most published rates, and likely from higher Los Angeles oxidant loads. Satellite observations from 2011 to 2014 confirmed that observed in situ transport patterns were representative and suggests much of the Chino Dairy Complex emissions are driven towards eastern Orange County, with a lesser amount transported to Palm Springs, CA. Given interest in mitigating husbandry health impacts from air pollution emissions, this study highlights how satellite observations can be leveraged to understand exposure and how multiple gas in situ emissions studies can inform on best practices given that emissions reduction of one gas could increase those of others. © 2016 Elsevier Ltd
BibTeX:
@article{Leifer2017,
  author = {Leifer, I. and Melton, C. and Tratt, D.M. and Buckland, K.N. and Clarisse, L. and Coheur, P. and Frash, J. and Gupta, M. and Johnson, P.D. and Leen, J.B. and Van Damme, M. and Whitburn, S. and Yurganov, L.},
  title = {Remote sensing and in situ measurements of methane and ammonia emissions from a megacity dairy complex: Chino, CA},
  journal = {Environmental Pollution},
  year = {2017},
  volume = {221},
  pages = {37-51},
  doi = {10.1016/j.envpol.2016.09.083}
}
Abstract: We analyze the ozone (O3) variability in the troposphere (from ground to 300 hPa) using 8 years (January 2008 to March 2016) of O3 profile measurements provided by the Infrared Atmospheric Sounding Interferometer (IASI) on board the MetOp satellite. The capability of IASI to monitor the year-to-year variability in that layer is examined first in terms of vertical sensitivity, a priori contribution, and correlations in the deseasonalized anomalies with the upper layers. We present global patterns of the main geophysical drivers (e.g., solar flux, Quasi-biennal Oscillation—QBO, North Atlantic Oscillation—NAO, and El Niño–Southern Oscillation—ENSO) of IASI O3 variations, obtained by applying appropriate annual and seasonal multivariate regression models on time series of spatially gridded averaged O3. The results show that the models are able to explain most of the O3 variability captured by IASI. Large O3 changes in the North Arctic/Euro-Atlantic sector and over the equatorial band are attributed to the NAO and the QBO effects, respectively. ENSO is modeled as the main contributor to the O3 variations in the tropical band where direct effects of warm and cool ENSO phases are highlighted with a clear tropical-extratropical gradient. A strong west-east gradient in the tropics is also found and likely reflects an indirect effect related to ENSO dry conditions. Finally, we also show that the ENSO perturbs the O3 variability far from the tropics into middle and high latitudes where a significant 4-month time-lag in the response of O3 to ENSO is identified for the first time. ©2017. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Wespes2017,
  author = {Wespes, C. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {O3 variability in the troposphere as observed by IASI over 2008–2016: Contribution of atmospheric chemistry and dynamics},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2017},
  volume = {122},
  pages = {2429-2451},
  doi = {10.1002/2016JD025875}
}
Abstract: A global frequency and intensity analysis of the infrared tetrad of 12C2H4 located in the 600-1500cm-1 region was carried out using the tensorial formalism developed in Dijon for X2Y4 asymmetric-top molecules. It relied on spectroscopic information available in the literature and retrieved from high-resolution Fourier transform infrared spectra recorded in Brussels in the frame of either the present or previous work. In particular, 645 and 131 line intensities have been respectively measured for the weak ν10 and ν4 bands. Including the Coriolis interactions affecting the upper vibrational levels 101, 71, 41 and 121, a total of 10 757 line positions and 1645 line intensities have been assigned and fitted with global root mean square deviations of 2.6×10-4cm-1 and 2.5%, respectively. Relying on the results of the present work and available in the literature, a list of parameters for 65 776 lines in the ν10, ν7, ν4 and ν12 bands of 12C2H4 was generated. To the best of our knowledge, this is the first time that a global intensity analysis is carried out in this range of the ethylene spectrum. © 2016 Elsevier Ltd.
BibTeX:
@article{Alkadrou2016,
  author = {Alkadrou, A. and Bourgeois, M.-T. and Rotger, M. and Boudon, V. and Vander Auwera, J.},
  title = {Global frequency and intensity analysis of the ν10/ν7/ν4/ν12 band system of 12C2H4 at 10 μm using the D2h Top Data System},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2016},
  volume = {182},
  pages = {158-171},
  doi = {10.1016/j.jqsrt.2016.05.024}
}
Abstract: A complete set of calculated vibration-rotation energies of 12C2H2 (X1Σg+) is provided for all vibrational states up to 13 000 cm-1 and some at higher energies, with rotational (J) and vibrational angular momentum (l) quantum numbers such that 0 ≤ J ≤ 100 and 0 ≤ |l| ≤ 20, respectively. The calculation is performed using a global effective Hamiltonian and related spectroscopic constants from the literature [B. Amyay et al., J. Mol. Spectrosc. 267, 80 (2011)], based on the polyad model. The numerical values of all related polyad matrix elements are also provided. The model and equations for the Hamiltonian matrix elements are gathered. The experimental acetylene database used for determining the parameters is listed. © 2016 AIP Publishing LLC for the National Institute of Standards and Technology.
BibTeX:
@article{Amyay2016a,
  author = {Amyay, B. and Fayt, A. and Herman, M. and Vander Auwera, J.},
  title = {Vibration-rotation spectroscopic database on acetylene, X1Σg+ (12C2H2)},
  journal = {Journal of Physical and Chemical Reference Data},
  year = {2016},
  volume = {45},
  article number = {023103},
  doi = {10.1063/1.4947297}
}
Abstract: We report new assignments of vibration-rotation line positions of methane (12CH4) in the so-called dyad (ν2/ν4) region (1100-1500 cm-1), and the resulting update of the vibration-rotation effective model of methane, previously reported by Nikitin et al. [Phys. Chem. Chem. Phys. 15, 10071 (2013)], up to and including the tetradecad. High resolution (0.01 cm-1) emission spectra of methane have been recorded up to about 1400 K using the high-enthalpy source developed at Institut de Physique de Rennes associated with the Fourier transform spectrometer of the SOLEIL synchrotron facility (AILES beamline). Analysis of these spectra allowed extending rotational assignments in the well-known cold band (dyad-ground state (GS)) and related hot bands in the pentad-dyad system (3000 cm-1) up to Jmax = 30 and 29, respectively. In addition, 8512 new transitions belonging to the octad-pentad (up to J = 28) and tetradecad-octad (up to J = 21) hot band systems were successfully identified. As a result, the MeCaSDa database of methane was significantly improved. The line positions assigned in this work, together with the information available in the literature, were fitted using 1096 effective parameters with a dimensionless standard deviation σ = 2.09. The root mean square deviations dRMS are 3.60 × 10-3 cm-1 for dyad-GS cold band, 4.47 ×10-3 cm-1 for the pentad-dyad, 5.43 × 10-3 cm-1 for the octad-pentad, and 4.70 × 10-3 cm-1 for the tetradecad-octad hot bands. The resulting new line list will contribute to improve opacity and radiative transfer models for hot atmospheres, such as those of hot-Jupiter type exoplanets. © 2016 AIP Publishing LLC.
BibTeX:
@article{Amyay2016,
  author = {Amyay, B. and Louviot, M. and Pirali, O. and Georges, R. and Vander Auwera, J. and Boudon, V.},
  title = {Global analysis of the high temperature infrared emission spectrum of 12CH4 in the dyad (ν 2/ ν 4) region},
  journal = {Journal of Chemical Physics},
  year = {2016},
  volume = {144},
  article number = {024312},
  doi = {10.1063/1.4939521}
}
Abstract: The vulnerability of the European airspace to volcanic eruptions was brought to the attention of the public and the scientific community by the 2010 eruptions of the Icelandic volcano Eyjafjallajökull. As a consequence of this event, ash concentration thresholds replaced the ĝ zero tolerance to ashĝ€ rule, drastically changing the requirements on satellite ash retrievals. In response to that, the ESA funded several projects aiming at creating an optimal end-to-end system for volcanic ash plume monitoring and prediction. Two of them, namely the SACS-2 and SMASH projects, developed and improved dedicated satellite-derived ash plume and sulfur dioxide level assessments. The validation of volcanic ash levels and height extracted from the GOME-2 and IASI instruments on board the MetOp-A satellite is presented in this work. EARLINET lidar measurements are compared to different satellite retrievals for two eruptive episodes in April and May 2010. Comparisons were also made between satellite retrievals and aircraft lidar data obtained with the UK's BAe-146-301 Atmospheric Research Aircraft (managed by the Facility for Airborne Atmospheric Measurements, FAAM) over the United Kingdom and the surrounding regions. The validation results are promising for most satellite products and are within the estimated uncertainties of each of the comparative data sets, but more collocation scenes would be desirable to perform a comprehensive statistical analysis. The satellite estimates and the validation data sets are better correlated for high ash optical depth values, with correlation coefficients greater than 0.8. The IASI retrievals show a better agreement concerning the ash optical depth and ash layer height when compared with the ground-based and airborne lidar data. © Author(s) 2016. CC Attribution 3.0 License.
BibTeX:
@article{Balis2016a,
  author = {Balis, D. and Koukouli, M.-E. and Siomos, N. and Dimopoulos, S. and Mona, L. and Pappalardo, G. and Marenco, F. and Clarisse, L. and J Ventress, L. and Carboni, E. and G Grainger, R. and Wang, P. and Tilstra, G. and Van Der A, R. and Theys, N. and Zehner, C.},
  title = {Validation of ash optical depth and layer height retrieved from passive satellite sensors using EARLINET and airborne lidar data: the case of the Eyjafjallajökull eruption},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {5705-5720},
  doi = {10.5194/acp-16-5705-2016}
}
Abstract: The 2010 eruptions of the Icelandic volcano Eyjafjallajokull attracted the attention of the public and the scientific community to the vulnerability of the European airspace to volcanic eruptions. The European Space Agency project "Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards", called for the creation of an optimal End-to-End System for Volcanic Ash Plume Monitoring and Prediction. This system is based on improved and dedicated satellite-derived ash plume and sulphur dioxide level assessments, as well as an extensive validation, using among others ground-based measurements (Koukouli et al., 2014). The validation of volcanic ash levels and height extracted from IASI/MetopA is presented in this work with emphasis on the ash plume height and ash optical depth levels. European Aerosol Research Lidar Network [EARLINET] lidar measurements are compared to different satellite estimates for two eruptive episodes. The validation results are extremely promising within the estimated uncertainties of each of the comparative datasets. © 2016 Owned by the authors, published by EDP Sciences.
BibTeX:
@conference{Balis2016,
  author = {Balis, D. and Siomos, N. and Koukouli, M. and Clarisse, L. and Carboni, E. and Ventress, L. and Grainger, R. and Mona, L. and Pappalardo, G.},
  title = {Validation of ASH Optical Depth and Layer Height from IASI using Earlinet Lidar Data},
  journal = {EPJ Web of Conferences},
  year = {2016},
  volume = {119},
  article number = {07006},
  doi = {10.1051/epjconf/201611907006}
}
Abstract: SO2 from volcanic eruptions is now operationally monitored from space in both the ultraviolet (UV) and thermal infrared (TIR) spectral range, but anthropogenic SO2 has almost solely been measured from UV sounders. Indeed, TIR instruments are well known to have a poor sensitivity to the planetary boundary layer (PBL), due to generally low thermal contrast (TC) between the ground and the air above it. Recent studies have demonstrated the capability of the Infrared Atmospheric Sounding Interferometer (IASI) to measure near-surface SO2 locally, for specific atmospheric conditions. In this work, we develop a retrieval method allowing the inference of SO2 near-surface concentrations from IASI measurements at a global scale. This method consists of two steps. Both are based on the computation of radiance indexes representing the strength of the SO2 ν3 band in IASI spectra. The first step allows the peak altitude of SO2 to be retrieved and near-surface SO2 to be selected. In the second step, 0-4 km columns of SO2 are inferred using a look-up table (LUT) approach. Using this new retrieval method, we obtain the first global distribution of near-surface SO2 from IASI-A, and identify the dominant anthropogenic hotspot sources and volcanic degassing. The 7-year daily time evolution of SO2 columns above two industrial source areas (Beijing in China and Sar Cheshmeh in Iran) is investigated and correlated to the seasonal variations of the parameters that drive the IASI sensitivity to the PBL composition. Apart from TC, we show that humidity is the most important parameter which determines IR sensitivity to nearsurface SO2 in the ν3 band. As IASI provides global measurements twice daily, the differences between the retrieved columns for the morning and evening orbits are investigated. This paper finally presents a first intercomparison of the measured 0-4 km columns with an independent iterative retrieval method and with observations of the Ozone Monitoring Instrument (OMI). © Author(s) 2016.
BibTeX:
@article{Bauduin2016,
  author = {Bauduin, S. and Clarisse, L. and Hadji-Lazaro, J. and Theys, N. and Clerbaux, C. and Coheur, P.-F.},
  title = {Retrieval of near-surface sulfur dioxide (SO2) concentrations at a global scale using IASI satellite observations},
  journal = {Atmospheric Measurement Techniques},
  year = {2016},
  volume = {9},
  pages = {721-740},
  doi = {10.5194/amt-9-721-2016}
}
Abstract: Collinear laser spectroscopy on Cu58-75 isotopes was performed at the CERN-ISOLDE radioactive ion beam facility. In this paper we report on the isotope shifts obtained from these measurements. State-of-the-art atomic physics calculations have been undertaken in order to determine the changes in mean-square charge radii δ(r2)A,A′ from the observed isotope shifts. A local minimum is observed in these radii differences at N=40, providing evidence for a weak N=40 sub-shell effect. However, comparison of δ(r2)A,A′ with a droplet model prediction including static deformation deduced from the spectroscopic quadrupole moments, points to the persistence of correlations at N=40. © 2016 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
BibTeX:
@article{Bissell2016,
  author = {Bissell, M.L. and Carette, T. and Flanagan, K.T. and Vingerhoets, P. and Billowes, J. and Blaum, K. and Cheal, B. and Fritzsche, S. and Godefroid, M. and Kowalska, M. and Krämer, J. and Neugart, R. and Neyens, G. and Nörtershäuser, W. and Yordanov, D.T.},
  title = {Cu charge radii reveal a weak sub-shell effect at N=40},
  journal = {Physical Review C - Nuclear Physics},
  year = {2016},
  volume = {93},
  article number = {064318},
  doi = {10.1103/PhysRevC.93.064318}
}
Abstract: The 2014-2015 Holuhraun lava-flood eruption of Bároarbunga volcano (Iceland) emitted prodigious amounts of sulfur dioxide into the atmosphere. This eruption caused a large-scale episode of air pollution throughout Western Europe in September 2014, the first event of this magnitude recorded in the modern era. We gathered chemistry-transport simulations and a wealth of complementary observations from satellite sensors (OMI, IASI), ground-based remote sensing (lidar, sunphotometry, differential optical absorption spectroscopy) and ground-level air quality monitoring networks to characterize both the spatial-temporal distributions of volcanic SO2 and sulfate aerosols as well as the dynamics of the planetary boundary layer. Time variations of dynamical and microphysical properties of sulfate aerosols in the aged low-tropospheric volcanic cloud, including loading, vertical distribution, size distribution and single scattering albedo, are provided. Retrospective chemistry-transport simulations at low horizontal resolution (25 km × 25 km) capture the correct temporal dynamics of this far-range air pollution event but fail to reproduce the correct magnitude of SO2 concentration at ground-level. Simulations at higher spatial resolution, relying on two nested domains with finest resolution of 7.3 km × 7.3 km, improve substantially the far-range vertical distribution of the volcanic cloud and subsequently the description of ground-level SO2 concentrations. However, remaining discrepancies between model and observations are shown to result from an inaccurate representation of the planetary boundary layer (PBL) dynamics. Comparison with lidar observations points out a systematic under-estimation of the PBL height by the model, whichever the PBL parameterization scheme. Such a shortcoming impedes the capture of the overlying Bároarbunga cloud into the PBL at the right time and in sufficient quantities. This study therefore demonstrates the key role played by the PBL dynamics in accurately modelling large-scale volcanogenic air pollution. © 2016 Author(s).
BibTeX:
@article{Boichu2016,
  author = {Boichu, M. and Chiapello, I. and Brogniez, C. and Péré, J.-C. and Thieuleux, F. and Torres, B. and Blarel, L. and Mortier, A. and Podvin, T. and Goloub, P. and Söhne, N. and Clarisse, L. and Bauduin, S. and Hendrick, F. and Theys, N. and Van Roozendael, M. and Tanré, D.},
  title = {Current challenges in modelling far-range air pollution induced by the 2014-2015 Bároarbunga fissure eruption (Iceland)},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {10831-10845},
  doi = {10.5194/acp-16-10831-2016}
}
Abstract: This paper presents an extensive intercomparison and validation for the ozone (O3) product measured by the two Infrared Atmospheric Sounding Interferometers (IASIs) launched on board the MetOp-A and MetOp-B satellites in 2006 and in 2012 respectively. IASI O3 total columns and vertical profiles obtained from Fast Optimal Retrievals on Layers for IASI (FORLI) v20140922 software (running up until recently) are validated against independent observations during the period 2008-2014 on a global scale. On average for the period 2013-2014, IASI-A and IASI-B total ozone columns (TOCs) retrieved using FORLI are consistent, with IASI-B providing slightly lower values with a global difference of only 0.2±0.8%. The comparison between IASI-A and IASI-B O3 vertical profiles shows differences within ±2% over the entire altitude range. Global validation results for 7 years of IASI TOCs from FORLI against the Global Ozone Monitoring Experiment-2 (GOME-2) launched on board MetOp-A and Brewer-Dobson data show that, on average, IASI overestimates the ultraviolet (UV) data by 5-6% with the largest differences found in the southern high latitudes. The comparison with UV-visible SAOZ (Système d'Analyse par Observation Zénithale) measurements shows a mean bias between IASI and SAOZ TOCs of 2-4% in the midlatitudes and tropics and 7% at the polar circle. Part of the discrepancies found at high latitudes can be attributed to the limited information content in the observations due to low brightness temperatures. The comparison with ozonesonde vertical profiles (limited to 30km) shows that on average IASI with FORLI processing underestimates O3 by ∼ 5-15% in the troposphere while it overestimates O3 by ∼ 10-40% in the stratosphere, depending on the latitude. The largest relative differences are found in the tropical tropopause region; this can be explained by the low O3 amounts leading to large relative errors. In this study, we also evaluate an updated version of FORLI-O3 retrieval software (v20151001), using look-up tables recalculated to cover a larger spectral range using the latest HITRAN spectroscopic database (HITRAN 2012) and implementing numerical corrections. The assessment of the new O3 product with the same set of observations as that used for the validation exercise shows a correction of ∼ 4% for the TOC positive bias when compared to the UV ground-based and satellite observations, bringing the overall global comparison to ∼ 1-2% on average. This improvement is mainly associated with a decrease in the retrieved O3 concentration in the middle stratosphere (above 30hPa/25km) as shown by the comparison with ozonesonde data. © Author(s) 2016.
BibTeX:
@article{Boynard2016,
  author = {Boynard, A. and Hurtmans, D. and Koukouli, M.E. and Goutail, F. and Bureau, J. and Safieddine, S. and Lerot, C. and Hadji-Lazaro, J. and Wespes, C. and Pommereau, J.-P. and Pazmino, A. and Zyrichidou, I. and Balis, D. and Barbe, A. and Mikhailenko, S.N. and Loyola, D. and Valks, P. and Van Roozendael, M. and Coheur, P.-F. and Clerbaux, C.},
  title = {Seven years of IASI ozone retrievals from FORLI: Validation with independent total column and vertical profile measurements},
  journal = {Atmospheric Measurement Techniques},
  year = {2016},
  volume = {9},
  pages = {4327-4353},
  doi = {10.5194/amt-9-4327-2016}
}
Abstract: Satellite instruments have been providing measurements of global volcanic emissions of sulfur dioxide (SO2) since 1978, based on observations in the ultraviolet (UV), infrared (IR) and microwave spectral bands. We review recent advances in satellite remote sensing of volcanic gases, focusing on increased instrument sensitivity to tropospheric SO2 emissions and techniques to determine volcanic plume altitude. A synthesis of  36 years of global UV, IR and microwave satellite measurements yields an updated assessment of the volcanic SO2 flux to the upper troposphere and lower stratosphere (UTLS) between 1978 and 2014 ( 1-Tg/yr). The present availability of multiple UV and IR satellite SO2 products provides increased confidence in calculated SO2 loadings for many eruptions. We examine the temporal and latitudinal distribution of volcanic SO2 emissions and reassess the relationship between eruptive SO2 discharge and eruption magnitude, finding a first-order correlation between SO2 emission and volcanic explosivity index (VEI), but with significant scatter. Based on the observed SO2-VEI relation, we estimate the fraction of eruptive SO2 emissions released by the smallest eruptions ( 0.48 Tg/yr), which is not recorded by satellite observations. A detailed breakdown of the sources of measured SO2 emissions reveals intuitively expected correlations between eruption frequency, SO2 loading and volcanic degassing style. We discuss new constraints on e-folding times for SO2 removal in volcanic plumes, and highlight recent measurements of volcanic hydrogen chloride (HCl) injections into the UTLS. An analysis of passive volcanic emissions of SO2 detected in Ozone Monitoring Instrument (OMI) SO2 data since 2004 provides new insight into the location and stability of the dominant sources of volcanic SO2 over the past decade. Since volcanic SO2 emissions constitute a random, highly variable perturbation to the atmosphere-climate system, continued monitoring of volcanic SO2 emissions from space by multiple UV and IR instruments to extend the current multi-decadal record is essential, and near-global, geostationary measurements of SO2 may be available by the end of the current decade. © 2016 The Authors.
BibTeX:
@article{Carn2016,
  author = {Carn, S.A. and Clarisse, L. and Prata, A.J.},
  title = {Multi-decadal satellite measurements of global volcanic degassing},
  journal = {Journal of Volcanology and Geothermal Research},
  year = {2016},
  volume = {311},
  pages = {99-134},
  doi = {10.1016/j.jvolgeores.2016.01.002}
}
Abstract: Observations of the green and red-doublet emission lines have previously been realized for several comets. We present here a chemistry-emission coupled model to study the production and loss mechanisms of the O(1S) and O(1D) states, which are responsible for the emission lines of interest for comet 67P/Churyumov-Gerasimenko. The recent discovery of O2 in significant abundance relative to water 3.80 ± 0.85 within the coma of 67P has been taken into consideration for the first time in such models. We evaluate the effect of the presence of O2 on the green to red-doublet emission intensity ratio, which is traditionally used to assess the CO2 abundance within cometary atmospheres. Model simulations, solving the continuity equation with transport, show that not taking O2 into account leads to an underestimation of the CO2 abundance within 67P, with a relative error of about 25%. This strongly suggests that the green to red-doublet emission intensity ratio alone is not a proper tool for determining the CO2 abundance, as previously suggested. Indeed, there is no compelling reason why O2 would not be a common cometary volatile, making revision of earlier assessments regarding the CO2 abundance in cometary atmospheres necessary. The large uncertainties of the CO2 photodissociation cross section imply that more studies are required in order to better constrain the O(1S) and O(1D) production through this mechanism. Space weather phenomena, such as powerful solar flares, could be used as tools for doing so, providing additional information on a good estimation of the O2 abundance within cometary atmospheres. ©2016. The Authors.
BibTeX:
@article{Cessateur2016,
  author = {Cessateur, G. and Keyser, J.D. and Maggiolo, R. and Gibbons, A. and Gronoff, G. and Gunell, H. and Dhooghe, F. and Loreau, J. and Vaeck, N. and Altwegg, K. and Bieler, A. and Briois, C. and Calmonte, U. and Combi, M.R. and Fiethe, B. and Fuselier, S.A. and Gombosi, T.I. and Hässig, M. and Le Roy, L. and Neefs, E. and Rubin, M. and Sémon, T.},
  title = {Photochemistry of forbidden oxygen lines in the inner coma of 67P/Churyumov-Gerasimenko},
  journal = {Journal of Geophysical Research A: Space Physics},
  year = {2016},
  volume = {121},
  pages = {804-816},
  doi = {10.1002/2015JA022013}
}
Abstract: In the first part of this chapter, the spectral content of the thermal infrared spectral region for the sounding of volcanic eruptions is explored through analysis of simulated and real observed spectra. Next, we review the literature on algorithms for the identification and retrieval of volcanic ash, both from broadband and hyperspectral infrared measurements. The final part of this chapter treats the topic of validation of satellite-based ash retrievals. © 2016 Elsevier Ltd. All rights reserved.
BibTeX:
@book{Clarisse2016,
  author = {Clarisse, L. and Prata, F.},
  title = {Infrared Sounding of Volcanic Ash},
  journal = {Volcanic Ash: Hazard Observation},
  year = {2016},
  pages = {189-215},
  doi = {10.1016/B978-0-08-100405-0.00017-3}
}
Abstract: Global distributions of atmospheric ammonia (NH3) measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI) contain valuable information on NH3 concentrations and variability in regions not yet covered by ground-based instruments. Due to their large spatial coverage and (bi-)daily overpasses, the satellite observations have the potential to increase our knowledge of the distribution of NH3 emissions and associated seasonal cycles. However the observations remain poorly validated, with only a handful of available studies often using only surface measurements without any vertical information. In this study, we present the first validation of the IASI-NH3 product using ground-based Fourier transform infrared spectroscopy (FTIR) observations. Using a recently developed consistent retrieval strategy, NH3 concentration profiles have been retrieved using observations from nine Network for the Detection of Atmospheric Composition Change (NDACC) stations around the world between 2008 and 2015. We demonstrate the importance of strict spatio-temporal collocation criteria for the comparison. Large differences in the regression results are observed for changing intervals of spatial criteria, mostly due to terrain characteristics and the short lifetime of NH3 in the atmosphere. The seasonal variations of both datasets are consistent for most sites. Correlations are found to be high at sites in areas with considerable NH3 levels, whereas correlations are lower at sites with low atmospheric NH3 levels close to the detection limit of the IASI instrument. A combination of the observations from all sites (<i>N</i>obs Combining double low line 547) give a mean relative difference of ĝ'32.4ĝ€±ĝ€(56.3)ĝ€%, a correlation <i>r</i> of 0.8 with a slope of 0.73. These results give an improved estimate of the IASI-NH3 product performance compared to the previous upper-bound estimates (-50 to +100%). © Author(s) 2016.
BibTeX:
@article{Dammers2016,
  author = {Dammers, E. and Palm, M. and Van Damme, M. and Vigouroux, C. and Smale, D. and Conway, S. and Toon, G.C. and Jones, N. and Nussbaumer, E. and Warneke, T. and Petri, C. and Clarisse, L. and Clerbaux, C. and Hermans, C. and Lutsch, E. and Strong, K. and Hannigan, J.W. and Nakajima, H. and Morino, I. and Herrera, B. and Stremme, W. and Grutter, M. and Schaap, M. and Kruit, R.J.W. and Notholt, J. and Coheur, P.-F. and Erisman, J.W.},
  title = {An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {10351-10368},
  doi = {10.5194/acp-16-10351-2016}
}
Abstract: Threshold-photoionization spectroscopy of cyanoacetylene (HC3N) and its 15N isotopologue has been investigated in the vacuum-ultraviolet range with a synchrotron-based experiment allowing to record threshold-photoelectron spectrum and photoion yield over a large energy range (from 88 500 to 177 500 cm-1, i.e., from 11 to 22 eV). Adiabatic ionization energies towards the three lowest electronic states X+ 2Π, A+ Σ+2, and B+ Π2 are derived from the threshold-photoelectron spectrum. A detailed description of the vibrational structure of these states is proposed leading to the determination of the vibrational frequencies for most modes. The vibrational assignments and the discussion about the electronic structure are supported by multireference ab initio calculations (CASPT2, MRCI). Unprecedented structures are resolved and tentatively assigned in the region of the B+ X transition. Exploratory calculations highlight the complexity of the electronic landscape of the cation up to approximately 10 eV above its ground state. © 2016 Author(s).
BibTeX:
@article{Desrier2016,
  author = {Desrier, A. and Romanzin, C. and Lamarre, N. and Alcaraz, C. and Gans, B. and Gauyacq, D. and Liévin, J. and Boyé-Péronne, S.},
  title = {Experimental and ab initio characterization of HC3N+ vibronic structure. I. Synchrotron-based threshold photo-electron spectroscopy},
  journal = {Journal of Chemical Physics},
  year = {2016},
  volume = {145},
  article number = {234310},
  doi = {10.1063/1.4972019}
}
Abstract: The present work reports results from systematic multiconfiguration Dirac-Hartree-Fock calculations of electronic isotope shift factors for a set of transitions between low-lying levels of neutral aluminium. These electronic quantities together with observed isotope shifts between different pairs of isotopes provide the changes in mean-square charge radii of the atomic nuclei. Two computational approaches are adopted for the estimation of the mass- and field-shift factors. Within these approaches, different models for electron correlation are explored in a systematic way to determine a reliable computational strategy and to estimate theoretical error bars of the isotope shift factors. © 2016 American Physical Society.
BibTeX:
@article{Filippin2016a,
  author = {Filippin, L. and Beerwerth, R. and Ekman, J. and Fritzsche, S. and Godefroid, M. and Jönsson, P.},
  title = {Multiconfiguration calculations of electronic isotope shift factors in Al i},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2016},
  volume = {94},
  article number = {062508},
  doi = {10.1103/PhysRevA.94.062508}
}
Abstract: Relativistic two-photon decay rates of the 2s1/2 and 2p1/2 states towards the 1s1/2 ground state of hydrogenic atoms are calculated by using numerically exact energies and wave functions obtained from the Dirac equation with the Lagrange-mesh method. This approach is an approximate variational method taking the form of equations on a grid because of the use of a Gauss quadrature approximation. Highly accurate values are obtained by a simple calculation involving different meshes for the initial, final, and intermediate wave functions and for the calculation of matrix elements. The accuracy of the results with a Coulomb potential is improved by several orders of magnitude in comparison with benchmark values from the literature. The general requirement of gauge invariance is also successfully tested, down to rounding errors. The method provides high accuracies for two-photon decay rates of a particle in other potentials and is applied to a hydrogen atom embedded in a Debye plasma simulated by a Yukawa potential. © 2016 American Physical Society.
BibTeX:
@article{Filippin2016,
  author = {Filippin, L. and Godefroid, M. and Baye, D.},
  title = {Relativistic two-photon decay rates with the Lagrange-mesh method},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2016},
  volume = {93},
  article number = {012517},
  doi = {10.1103/PhysRevA.93.012517}
}
Abstract: The present work reports results from systematic multiconfiguration Dirac-Hartree-Fock calculations of isotope shifts for several well-known transitions in neutral magnesium. Relativistic normal and specific mass shift factors as well as the electronic probability density at the origin are calculated. Combining these electronic quantities with available nuclear data, energy and transition level shifts are determined for the Mg26-Mg24 pair of isotopes. Different models for electron correlation are adopted. It is shown that, although valence and core-valence models provide accurate values for the isotope shifts, the inclusion of core-core excitations in the computational strategy significantly improves the accuracy of the transition energies and normal mass shift factors. © 2016 American Physical Society.
BibTeX:
@article{Filippin2016b,
  author = {Filippin, L. and Godefroid, M. and Ekman, J. and Jönsson, P.},
  title = {Core correlation effects in multiconfiguration calculations of isotope shifts in Mg I},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2016},
  volume = {93},
  article number = {062512},
  doi = {10.1103/PhysRevA.93.062512}
}
Abstract: Multiconfiguration wave function expansions combined with configuration interaction methods are a method of choice for complex atoms where atomic state functions are expanded in a basis of configuration state functions. Combined with a variational method such as the multiconfiguration Hartree-Fock (MCHF) or multiconfiguration Dirac-Hartree-Fock (MCDHF), the associated set of radial functions can be optimized for the levels of interest. The present review updates the variational MCHF theory to include MCDHF, describes the multireference single and double process for generating expansions and the systematic procedure of a computational scheme for monitoring convergence. It focuses on the calculations of energies and wave functions from which other atomic properties can be predicted such as transition rates, hyperfine structures and isotope shifts, for example. © 2016 IOP Publishing Ltd.
BibTeX:
@article{Fischer2016,
  author = {Fischer, C.F. and Godefroid, M. and Brage, T. and Jönsson, P. and Gaigalas, G.},
  title = {Advanced multiconfiguration methods for complex atoms: I. Energies and wave functions},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2016},
  volume = {49},
  article number = {182004},
  doi = {10.1088/0953-4075/49/18/182004}
}
Abstract: Spectra of 99% isotopically pure 15NH3 were recorded using cavity ring-down (CRD, 6567-6639 cm-1) and Fourier transform (FT, 6350-6985 cm-1) spectroscopy under jet cooled and room temperature conditions, respectively. Measured line positions on both data sets improve on literature values, in particular by one order of magnitude for the ν1+ν3 band. A room temperature list of line positions, with approximate line intensities, is provided, much more complete and precise than presently available. Line broadening effects in the CRD spectrum allowed lines with J'''- values between 0 and 3 to be identified. Ground state combination differences were used to refine the assignments, further assisted by intensity ratios between the two data sets. Reliable values for J, K and inversion symmetry of the ground state vibrational levels, as well as further information on a/s doublets could be obtained, updating and extending literature assignments. © 2016 Elsevier Ltd.
BibTeX:
@article{Foeldes2016,
  author = {Földes, T. and Vanfleteren, T. and Rizopoulos, A. and Herman, M. and Vander Auwera, J. and Softley, T.P. and Di Lonardo, G. and Fusina, L.},
  title = {High-resolution room temperature and jet-cooled spectroscopic investigation of 1 5NH3 in the ν1+ν3 band region (1.51 μm)},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2016},
  volume = {179},
  pages = {112-125},
  doi = {10.1016/j.jqsrt.2016.03.018}
}
Abstract: Ammonia (NH3), whose main source in the troposphere is agriculture, is an important gaseous precursor of atmospheric particulate matter (PM). We derived daily ammonia emissions using NH3 total columns measured from the Infrared Atmospheric Sounding Interferometer (IASI) on board Metop-A, at a relatively high spatial resolution (grid cell of 0.5° × 0.5°). During the European spring haze episodes of 24–31 March 2012 and 8–15 March 2014, IASI reveals NH3 total column magnitudes highlighting higher NH3 emissions over central Europe (especially over Germany, Czech Republic, and eastern France) from the ones provided by the European reference European Monitoring and Evaluation Programme inventory. These ammonia emissions exhibit in addition a large day-to-day variability, certainly due to spreading practices. The increase of NH3 emissions in the model, that reaches +300% locally, leads to an increase of both NH3 and PM2.5 surface concentrations and allows for a better comparison with independent measurements (in terms of bias, root-mean-square error, and correlation). This study suggests that there are good prospects for better quantifying NH3 emissions by atmospheric inversions. ©2016. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Fortems-Cheiney2016,
  author = {Fortems-Cheiney, A. and Dufour, G. and Hamaoui-Laguel, L. and Foret, G. and Siour, G. and Van Damme, M. and Meleux, F. and Coheur, P.-F. and Clerbaux, C. and Clarisse, L. and Favez, O. and Wallasch, M. and Beekmann, M.},
  title = {Unaccounted variability in NH3 agricultural sources detected by IASI contributing to European spring haze episode},
  journal = {Geophysical Research Letters},
  year = {2016},
  volume = {43},
  pages = {5475-5482},
  doi = {10.1002/2016GL069361}
}
Abstract: Vacuum-ultraviolet pulsed-field-ionization zero-kinetic-energy photoelectron spectra of X+Π2←XΣ+1 and B+Π2←XΣ+1 transitions of the HC314N and HC315N isotopologues of cyanoacetylene have been recorded. The resolution of the photoelectron spectra allowed us to resolve the vibrational structures and the spin-orbit splittings in the cation. Accurate values of the adiabatic ionization potentials of the two isotopologues (EI/hc(HC314N)=93 909(2) cm-1 and EI/hc(HC315N)=93 912(2) cm-1), the vibrational frequencies of the ν2, ν6, and ν7 vibrational modes, and the spin-orbit coupling constant (ASO = -44(2) cm-1) of the X+Π2 cationic ground state have been derived from the measurements. Using ab initio calculations, the unexpected structure of the B+Π2←XΣ+1 transition is tentatively attributed to a conical intersection between the A+ and B+ electronic states of the cation. © 2016 Author(s).
BibTeX:
@article{Gans2016,
  author = {Gans, B. and Lamarre, N. and Broquier, M. and Liévin, J. and Boyé-Péronne, S.},
  title = {Experimental and ab initio characterization of HC3N+ vibronic structure. II. High-resolution VUV PFI-ZEKE spectroscopy},
  journal = {Journal of Chemical Physics},
  year = {2016},
  volume = {145},
  article number = {234309},
  doi = {10.1063/1.4972018}
}
Abstract: Mathematical models have provided important insights into acute viral dynamics within individual patients. In this paper, we study the simplest target cell-limited models to investigate the within-host dynamics of influenza A virus infection in humans. Despite the biological simplicity of the models, we show how these can be used to understand the severity of the infection and the key attributes of possible immunotherapy and antiviral drugs for the treatment of infection at different times post infection. Through an analytic approach, we derive and estimate simple summary biological quantities that can provide novel insights into the infection dynamics and the definition of clinical endpoints. We focus on nine quantities, including the area under the viral load curve, peak viral load, the time to peak viral load and the level of cell death due to infection. Using Markov chain Monte Carlo methods, we fitted the models to data collected from 12 untreated volunteers who participated in two clinical studies that tested the antiviral drugs oseltamivir and zanamivir. Based on the results, we also discuss various difficulties in deriving precise estimates of the parameters, even in the very simple models considered, when experimental data are limited to viral load measures and/or there is a limited number of viral load measurements post infection. © 2016 The Authors.
BibTeX:
@article{Hadjichrysanthou2016,
  author = {Hadjichrysanthou, C. and Cauët, E. and Lawrence, E. and Vegvari, C. and De Wolf, F. and Anderson, R.M.},
  title = {Understanding the within-host dynamics of influenza A virus: From theory to clinical implications},
  journal = {Journal of the Royal Society Interface},
  year = {2016},
  volume = {13},
  article number = {20160289},
  doi = {10.1098/rsif.2016.0289}
}
Abstract: Fourier transform absorption spectra of the 2-0 band of 12C16O mixed with CO2 have been recorded at total pressures from 156 to 1212hPa and at 4 different temperatures between 240K and 283K. CO2 pressure-induced line broadening and line shift coefficients, and the temperature dependence of the former have been measured including line mixing using a multi-spectrum non-linear least squares fitting technique. Different line shape models have been considered to take into account the Dicke narrowing or speed dependence effects. Measured line-shape parameters were compared with theoretical values, calculated for individual temperatures using a semi-empirical method and the Exponential Power Gap (EPG) law. © 2016 Elsevier Inc.
BibTeX:
@article{Hashemi2016,
  author = {Hashemi, R. and Predoi-Cross, A. and Dudaryonok, A.S. and Lavrentieva, N.N. and Vandaele, A.C. and Vander Auwera, J.},
  title = {CO2 pressure broadening and shift coefficients for the 2-0 band of 12C16O},
  journal = {Journal of Molecular Spectroscopy},
  year = {2016},
  doi = {10.1016/j.jms.2016.02.014}
}
Abstract: The literature on the high-resolution spectroscopic investigation of molecular complexes containing small polyatomic species excited in their vibrational overtones is reviewed. They turn out to be complexes containing acetylene, ammonia and water, mainly excited in their 2CH, 2NH and 2OH vibrations, respectively. The majority of results published on these systems was obtained using an instrumental set-up based on cw-cavity ring-down spectroscopy, built in the ‘Laboratoire de Chimie quantique et Photophysique’ at the ‘Université libre de Bruxelles’ (CQP/ULB) and named FANTASIO+, which is described. It allowed retrieving upper state vibrational predissociation lifetimes, which are highlighted together with more results. The sequence of experiments at CQP/ULB prior and along the line of those supporting the investigation of molecular complexes is briefly illustrated. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
BibTeX:
@article{Herman2016,
  author = {Herman, M. and Földes, T. and Didriche, K. and Lauzin, C. and Vanfleteren, T.},
  title = {Overtone spectroscopy of molecular complexes containing small polyatomic molecules},
  journal = {International Reviews in Physical Chemistry},
  year = {2016},
  volume = {35},
  pages = {243-295},
  doi = {10.1080/0144235X.2016.1171039}
}
Abstract: The GEISA database (Gestion et Etude des Informations Spectroscopiques Atmosphériques: Management and Study of Atmospheric Spectroscopic Information) has been developed and maintained by the ARA/ABC(t) group at LMD since 1974. GEISA is constantly evolving, taking into account the best available spectroscopic data. This paper presents the 2015 release of GEISA (GEISA-2015), which updates the last edition of 2011 and celebrates the 40th anniversary of the database. Significant updates and additions have been implemented in the three following independent databases of GEISA. The “line parameters database” contains 52 molecular species (118 isotopologues) and transitions in the spectral range from 10−6 to 35,877.031 cm−1, representing 5,067,351 entries, against 3,794,297 in GEISA-2011. Among the previously existing molecules, 20 molecular species have been updated. A new molecule (SO3) has been added. HDO, isotopologue of H2O, is now identified as an independent molecular species. Seven new isotopologues have been added to the GEISA-2015 database. The “cross section sub-database” has been enriched by the addition of 43 new molecular species in its infrared part, 4 molecules (ethane, propane, acetone, acetonitrile) are also updated; they represent 3% of the update. A new section is added, in the near-infrared spectral region, involving 7 molecular species: CH3CN, CH3I, CH3O2, H2CO, HO2, HONO, NH3. The “microphysical and optical properties of atmospheric aerosols sub-database” has been updated for the first time since 2003. It contains more than 40 species originating from NCAR and 20 from the ARIA archive of Oxford University. As for the previous versions, this new release of GEISA and associated management software facilities are implemented and freely accessible on the AERIS/ESPRI atmospheric chemistry data center website. © 2016 Elsevier Inc.
BibTeX:
@article{Jacquinet-Husson2016a,
  author = {Jacquinet-Husson, N. and Armante, R. and Scott, N.A. and Chédin, A. and Crépeau, L. and Boutammine, C. and Bouhdaoui, A. and Crevoisier, C. and Capelle, V. and Boonne, C. and Poulet-Crovisier, N. and Barbe, A. and Chris Benner, D. and Boudon, V. and Brown, L.R. and Buldyreva, J. and Campargue, A. and Coudert, L.H. and Devi, V.M. and Down, M.J. and Drouin, B.J. and Fayt, A. and Fittschen, C. and Flaud, J.-M. and Gamache, R.R. and Harrison, J.J. and Hill, C. and Hodnebrog, Ø. and Hu, S.-M. and Jacquemart, D. and Jolly, A. and Jiménez, E. and Lavrentieva, N.N. and Liu, A.-W. and Lodi, L. and Lyulin, O.M. and Massie, S.T. and Mikhailenko, S. and Müller, H.S.P. and Naumenko, O.V. and Nikitin, A. and Nielsen, C.J. and Orphal, J. and Perevalov, V.I. and Perrin, A. and Polovtseva, E. and Predoi-Cross, A. and Rotger, M. and Ruth, A.A. and Yu, S.S. and Sung, K. and Tashkun, S.A. and Tennyson, J. and Tyuterev, V.G. and Vander Auwera, J. and Voronin, B.A. and Makie, A.},
  title = {The 2015 edition of the GEISA spectroscopic database},
  journal = {Journal of Molecular Spectroscopy},
  year = {2016},
  volume = {327},
  pages = {31-72},
  doi = {10.1016/j.jms.2016.06.007}
}
BibTeX:
@article{Jacquinet-Husson2016,
  author = {Jacquinet-Husson, N. and Flaud, J.-M. and Gamache, R.R. and Predoi-Cross, A. and Vander Auwera, J.},
  title = {New visions of spectroscopic databases: An introduction to the special issue},
  journal = {Journal of Molecular Spectroscopy},
  year = {2016},
  volume = {326},
  pages = {1-4},
  doi = {10.1016/j.jms.2016.07.006}
}
Abstract: Multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations and relativistic configuration interaction (RCI) calculations are performed for states of the 3s23p2, 3s3p3 and 3s23p3d configurations in the Si-like ions Ti IX - Ge XIX, Sr XXV, Zr XXVII and Mo XXIX. Valence and core-valence electron correlation effects are accounted for through large configuration state function expansions. Calculated energy levels are compared with data from other calculations and with experimental data from the reference databases. Lifetime and transition rates along with uncertainty estimations are given for all ions. Energies from the calculations are in excellent agreement with observations and computed wavelength are almost of spectroscopic accuracy, aiding line identification in spectra. © 2015 ESO.
BibTeX:
@article{Joensson2016,
  author = {Jönsson, P. and Radžiute, L. and Gaigalas, G. and Godefroid, M.R. and Marques, J.P. and Brage, T. and Froese Fischer, C. and Grant, I.P.},
  title = {Accurate multiconfiguration calculations of energy levels, lifetimes, and transition rates for the silicon isoelectronic sequence: Ti IX - Ge XIX, Sr XXV, Zr XXVII, Mo XXIX},
  journal = {Astronomy and Astrophysics},
  year = {2016},
  volume = {585},
  article number = {A26},
  doi = {10.1051/0004-6361/201527106}
}
Abstract: A theoretical rate constant for the associative detachment reaction Rb(2S) + OH-(1Σ+) → RbOH(1Σ+) + e- of 4 × 10-10 cm3 s-1 at 300 K has been calculated. This result agrees with the experimental rate constant of 2 - 1 + 2 × 1 0 - 10 cm 3 s - 1 obtained by Deiglmayr et al. [Phys. Rev. A 86, 043438 (2012)] for a temperature between 200 K and 600 K. A Langevin-based dynamics which depends on the crossing point between the anion (RbOH-) and neutral (RbOH) potential energy surfaces has been used. The calculations were performed using the ECP28MDF effective core potential to describe the rubidium atom at the CCSD(T) level of theory and extended basis sets. The effect of ECPs and basis set on the height of the crossing point, and hence the rate constant, has been investigated. The temperature dependence of the latter is also discussed. Preliminary work on the potential energy surface for the excited reaction channel Rb(2P) + OH-(1Σ+) calculated at the CASSCF-icMRCI level of theory is presented. We qualitatively discuss the charge transfer and associative detachment reactions arising from this excited entrance channel. © 2016 Author(s).
BibTeX:
@article{Kas2016,
  author = {Kas, M. and Loreau, J. and Liévin, J. and Vaeck, N.},
  title = {Ab initio study of reactive collisions between Rb(2 S) or Rb(2 P) and OH-(1Σ+)},
  journal = {Journal of Chemical Physics},
  year = {2016},
  volume = {144},
  article number = {204306},
  doi = {10.1063/1.4950784}
}
Abstract: Interest in stratospheric aerosol and its role in climate have increased over the last decade due to the observed increase in stratospheric aerosol since 2000 and the potential for changes in the sulfur cycle induced by climate change. This review provides an overview about the advances in stratospheric aerosol research since the last comprehensive assessment of stratospheric aerosol was published in 2006. A crucial development since 2006 is the substantial improvement in the agreement between in situ and space-based inferences of stratospheric aerosol properties during volcanically quiescent periods. Furthermore, new measurement systems and techniques, both in situ and space based, have been developed for measuring physical aerosol properties with greater accuracy and for characterizing aerosol composition. However, these changes induce challenges to constructing a long-term stratospheric aerosol climatology. Currently, changes in stratospheric aerosol levels less than 20% cannot be confidently quantified. The volcanic signals tend to mask any nonvolcanically driven change, making them difficult to understand. While the role of carbonyl sulfide as a substantial and relatively constant source of stratospheric sulfur has been confirmed by new observations and model simulations, large uncertainties remain with respect to the contribution from anthropogenic sulfur dioxide emissions. New evidence has been provided that stratospheric aerosol can also contain small amounts of nonsulfate matter such as black carbon and organics. Chemistry-climate models have substantially increased in quantity and sophistication. In many models the implementation of stratospheric aerosol processes is coupled to radiation and/or stratospheric chemistry modules to account for relevant feedback processes. ©2016. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Kremser2016,
  author = {Kremser, S. and Thomason, L.W. and von Hobe, M. and Hermann, M. and Deshler, T. and Timmreck, C. and Toohey, M. and Stenke, A. and Schwarz, J.P. and Weigel, R. and Fueglistaler, S. and Prata, F.J. and Vernier, J.-P. and Schlager, H. and Barnes, J.E. and Antuña-Marrero, J.-C. and Fairlie, D. and Palm, M. and Mahieu, E. and Notholt, J. and Rex, M. and Bingen, C. and Vanhellemont, F. and Bourassa, A. and Plane, J.M.C. and Klocke, D. and Carn, S.A. and Clarisse, L. and Trickl, T. and Neely, R. and James, A.D. and Rieger, L. and Wilson, J.C. and Meland, B.},
  title = {Stratospheric aerosol—Observations, processes, and impact on climate},
  journal = {Reviews of Geophysics},
  year = {2016},
  volume = {54},
  pages = {278-335},
  doi = {10.1002/2015RG000511}
}
Abstract: Methane (CH4) and ammonia (NH3) directly and indirectly affect the atmospheric radiative balance with the latter leading to aerosol generation. Both have important spectral features in the Thermal InfraRed (TIR) that can be studied by remote sensing, with NH3 allowing discrimination of husbandry from other CH4 sources. Airborne hyperspectral imagery was collected for the Chino Dairy Complex in the Los Angeles Basin as well as in situ CH4, carbon dioxide (CO2) and NH3 data. TIR data showed good spatial agreement with in situ measurements and showed significant emissions heterogeneity between dairies. Airborne remote sensing mapped plume transport for ∼20 km downwind, documenting topographic effects on plume advection. Repeated multiple gas in situ measurements showed that emissions were persistent on half-year timescales. Inversion of one dairy plume found annual emissions of 4.1 × 105 kg CH4, 2.2 × 105 kg NH3, and 2.3 × 107 kg CO2, suggesting 2300, 4000, and 2100 head of cattle, respectively, and Chino Dairy Complex emissions of 42 Gg CH4 and 8.4 Gg NH3 implying ∼200k cows, ∼30% more than Peischl et al. (2013) estimated for June 2010. Far-field data showed chemical conversion and/or deposition of Chino NH3 occurs within the confines of the Los Angeles Basin on a four to six h timescale, faster than most published rates, and likely from higher Los Angeles oxidant loads. Satellite observations from 2011 to 2014 confirmed that observed in situ transport patterns were representative and suggests much of the Chino Dairy Complex emissions are driven towards eastern Orange County, with a lesser amount transported to Palm Springs, CA. Given interest in mitigating husbandry health impacts from air pollution emissions, this study highlights how satellite observations can be leveraged to understand exposure and how multiple gas in situ emissions studies can inform on best practices given that emissions reduction of one gas could increase those of others. © 2016 Elsevier Ltd.
BibTeX:
@article{Leifer2016,
  author = {Leifer, I. and Melton, C. and Tratt, D.M. and Buckland, K.N. and Clarisse, L. and Coheur, P. and Frash, J. and Gupta, M. and Johnson, P.D. and Leen, J.B. and Van Damme, M. and Whitburn, S. and Yurganov, L.},
  title = {Remote sensing and in situ measurements of methane and ammonia emissions from a megacity dairy complex: Chino, CA},
  journal = {Environmental Pollution},
  year = {2016},
  doi = {10.1016/j.envpol.2016.09.083}
}
Abstract: We calculated the magnetic dipole hyperfine interaction constants and the electric field gradients of and levels of Ne I by using the multiconfiguration Dirac-Hartree-Fock method. The electronic factors contributing to the isotope shifts were also estimated for the transition connecting these two states. Electron correlation and relativistic effects including the Breit interaction were investigated in detail. Combining with recent measurements, we extracted the nuclear quadrupole moment values for 20Ne and 23Ne with a smaller uncertainty than the current available data. Isotope shifts in the transition based on the present calculated field- and mass-shift parameters are in good agreement with the experimental values. However, the field shifts in this transition are two or three orders of magnitude smaller than the mass shifts, making rather difficult to deduce changes in nuclear-charge mean-square radii. According to our theoretical predictions, we suggest using instead transitions connecting levels arising from the 2p53s configuration to the ground state, for which the normal mass shift and specific mass shift contributions counteract each other, producing relatively small mass shifts that are only one order of magnitude larger than relatively large field shifts, especially for the transition. © 2016 IOP Publishing Ltd.
BibTeX:
@article{Li2016,
  author = {Li, J. and Godefroid, M. and Wang, J.},
  title = {Atomic parameters for the 2{p}^{5}3p\;{}^{2}{[3/2]}-{2}-2{p}^{5}3s\;{}^{2}{[3/2]}-{2}^{o}transition of Ne i relevant in nuclear physics},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2016},
  volume = {49},
  article number = {115002},
  doi = {10.1088/0953-4075/49/11/115002}
}
Abstract: High resolution (0.011 cm-1) room temperature (295 K) Fourier transform absorption spectra (FTS) of acetylene have been analyzed in the 8280-8700 cm-1 range dominated by the ν1+ν2+ν3 band at 8512 cm-1. Line positions and intensities were retrieved from FTS spectra recorded at 3.84 and 56.6 hPa. As a result, a list of 1001 lines was constructed with intensities ranging between about 2×10-26 and 10-22 cm/molecule. Comparison with accurate predictions provided by a global effective operator model led to the assignment of 629 12C2H2 lines. In addition, 114 lines of the 13C12CH2 isotopologue were assigned using information available in the literature. The 12C2H2 lines belong to thirteen bands, nine of which being newly reported. The 13C12CH2 lines belong to three bands, the intensities of which being reported for the first time. Spectroscopic parameters of the 12C2H2 upper vibrational levels were derived from band-by-band analyses of the line positions (typical rms are on the order of 0.002 cm-1). Three of the analyzed bands were found to be affected by rovibrational perturbations, which are discussed in the frame of a global effective Hamiltonian. The obtained line parameters are compared with those of the two bands included in the HITRAN 2012 database. © 2015 Elsevier Ltd.
BibTeX:
@article{Lyulin2016,
  author = {Lyulin, O.M. and Vander Auwera, J. and Campargue, A.},
  title = {The Fourier transform absorption spectrum of acetylene between 8280 and 8700 cm-1},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2016},
  volume = {177},
  pages = {234-240},
  doi = {10.1016/j.jqsrt.2015.11.026}
}
Abstract: Improved line positions and intensities have been generated for the 7.6 m spectral region of nitric acid. They were obtained relying on a recent reinvestigation of the nitric acid band system at 7.6 m and comparisons of HNO3 volume mixing ratio profiles retrieved from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) limb emission radiances in the 11 and 7.6 m domains. This has led to an improved database called MIPAS-2015. Comparisons with available laboratory information (individual line intensities, integrated absorption cross sections, and absorption cross sections) show that MIPAS-2015 provides an improved description of the 7.6 m region of nitric acid. This study should help to improve HNO3 satellite retrievals by allowing measurements to be performed simultaneously in the 11 and 7.6 m micro-windows. In particular, it should be useful to analyze existing MIPAS and IASI spectra as well as spectra to be recorded by the forthcoming Infrared Atmospheric Sounding Interferometer-New Generation (IASI-NG) instrument. © 2016 Author(s).
BibTeX:
@article{Perrin2016,
  author = {Perrin, A. and Flaud, J.-M. and Ridolfi, M. and Vander Auwera, J. and Carlotti, M.},
  title = {MIPAS database: New HNO3 line parameters at 7.6 μm validated with MIPAS satellite measurements},
  journal = {Atmospheric Measurement Techniques},
  year = {2016},
  volume = {9},
  pages = {2067-2076},
  doi = {10.5194/amt-9-2067-2016}
}
Abstract: Formic acid (HCOOH) is one of the most abundant volatile organic compounds in the atmosphere. It is a major contributor to rain acidity in remote areas. There are, however, large uncertainties on the sources and sinks of HCOOH and therefore HCOOH is misrepresented by global chemistry-transport models. This work presents global distributions from 2008 to 2014 as derived from the measurements of the Infrared Atmospheric Sounding Interferometer (IASI), based on conversion factors between brightness temperature differences and representative retrieved total columns over seven regions: Northern Africa, southern Africa, Amazonia, Atlantic, Australia, Pacific, and Russia. The dependence of the measured HCOOH signal on the thermal contrast is taken into account in the conversion method. This conversion presents errors lower than 20% for total columns ranging between 0.5 and 1×1016 molec cm-2 but reaches higher values, up to 78 %, for columns that are lower than 0:3×1016 molec cm-2. Signatures from biomass burning events are highlighted, such as in the Southern Hemisphere and in Russia, as well as biogenic emission sources, e.g., over the eastern USA. A comparison between 2008 and 2014 with ground-based Fourier transform infrared spectroscopy (FTIR) measurements obtained at four locations (Maido and Saint-Denis at La Réunion, Jungfraujoch, and Wollongong) is shown. Although IASI columns are found to correlate well with FTIR data, a large bias (> 100 %) is found over the two sites at La Réunion. A better agreement is found at Wollongong with a negligible bias. The comparison also highlights the difficulty of retrieving total columns from IASI measurements over mountainous regions such as Jungfraujoch. A comparison of the retrieved columns with the global chemistry-transport model IMAGESv2 is also presented, showing good representation of the seasonal and interannual cycles over America, Australia, Asia, and Siberia. A global model underestimation of the distribution and a misrepresentation of the seasonal cycle over India are also found. A small positive trend in the IASI columns is observed over Australia, Amazonia, and India over the 2008-2014 period (from 0.7 to 1.5%year-1), while a decrease of ∼0.8% year-1 is measured over Siberia. © Author(s) 2016.
BibTeX:
@article{Pommier2016,
  author = {Pommier, M. and Clerbaux, C. and Coheur, P.-F. and Mahieu, E. and Müller, J.-F. and Paton-Walsh, C. and Stavrakou, T. and Vigouroux, C.},
  title = {HCOOH distributions from IASI for 2008-2014: Comparison with ground-based FTIR measurements and a global chemistry-transport model},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {8963-8981},
  doi = {10.5194/acp-16-8963-2016}
}
Abstract: Producing a global and comprehensive description of atmospheric aerosols requires integration of ground-based, airborne, satellite and model datasets. Due to its complexity, aerosol monitoring requires the use of several data records with complementary information content. This paper describes the lessons learned while developing and qualifying algorithms to generate aerosol Climate Data Records (CDR) within the European Space Agency (ESA) Aerosol_cci project. An iterative algorithm development and evaluation cycle involving core users is applied. It begins with the application-specific refinement of user requirements, leading to algorithm development, dataset processing and independent validation followed by user evaluation. This cycle is demonstrated for a CDR of total Aerosol Optical Depth (AOD) from two subsequent dual-view radiometers. Specific aspects of its applicability to other aerosol algorithms are illustrated with four complementary aerosol datasets. An important element in the development of aerosol CDRs is the inclusion of several algorithms evaluating the same data to benefit from various solutions to the ill-determined retrieval problem. The iterative approach has produced a 17-year AOD CDR, a 10-year stratospheric extinction profile CDR and a 35-year Absorbing Aerosol Index record. Further evolution cycles have been initiated for complementary datasets to provide insight into aerosol properties (i.e., dust aerosol, aerosol absorption). © 2016 by the authors.
BibTeX:
@article{Popp2016,
  author = {Popp, T. and De Leeuw, G. and Bingen, C. and Brühl, C. and Capelle, V. and Chedin, A. and Clarisse, L. and Dubovik, O. and Grainger, R. and Griesfeller, J. and Heckel, A. and Kinne, S. and Klüser, L. and Kosmale, M. and Kolmonen, P. and Lelli, L. and Litvinov, P. and Mei, L. and North, P. and Pinnock, S. and Povey, A. and Robert, C. and Schulz, M. and Sogacheva, L. and Stebel, K. and Zweers, D.S. and Thomas, G. and Tilstra, L.G. and Vandenbussche, S. and Veefkind, P. and Vountas, M. and Xue, Y.},
  title = {Development, production and evaluation of aerosol climate data records from European satellite observations (Aerosol_cci)},
  journal = {Remote Sensing},
  year = {2016},
  volume = {8},
  article number = {421},
  doi = {10.3390/rs8050421}
}
BibTeX:
@article{Predoi-Cross2016,
  author = {Predoi-Cross, A. and Unni, A.V. and Liu, W. and Schofield, I. and Holladay, C. and McKellar, A.R.W. and Hurtmans, D.},
  title = {Corrigendum to "Line shape parameters measurement and computations for self-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 bands, line mixing, and speed dependence" [J. Mol. Spectrosc. 245 (2007) 34-51]},
  journal = {Journal of Molecular Spectroscopy},
  year = {2016},
  volume = {322},
  pages = {55},
  doi = {10.1016/j.jms.2015.11.005}
}
Abstract: The ability of seven state-of-the-art chemistry-aerosol models to reproduce distributions of tropospheric ozone and its precursors, as well as aerosols over eastern Asia in summer 2008, is evaluated. The study focuses on the performance of models used to assess impacts of pollutants on climate and air quality as part of the EU ECLIPSE project. Models, run using the same ECLIPSE emissions, are compared over different spatial scales to in situ surface, vertical profiles and satellite data. Several rather clear biases are found between model results and observations, including overestimation of ozone at rural locations downwind of the main emission regions in China, as well as downwind over the Pacific. Several models produce too much ozone over polluted regions, which is then transported downwind. Analysis points to different factors related to the ability of models to simulate VOC-limited regimes over polluted regions and NOx limited regimes downwind. This may also be linked to biases compared to satellite NO2, indicating overestimation of NO2 over and to the north of the northern China Plain emission region. On the other hand, model NO2 is too low to the south and west of this region and over South Korea/Japan. Overestimation of ozone is linked to systematic underestimation of CO particularly at rural sites and downwind of the main Chinese emission regions. This is likely to be due to enhanced destruction of CO by OH. Overestimation of Asian ozone and its transport downwind implies that radiative forcing from this source may be overestimated. Model-observation discrepancies over Beijing do not appear to be due to emission controls linked to the Olympic Games in summer 2008.

With regard to aerosols, most models reproduce the satellite-derived AOD patterns over eastern China. Our study nevertheless reveals an overestimation of ECLIPSE model mean surface BC and sulphate aerosols in urban China in summer 2008. The effect of the short-term emission mitigation in Beijing is too weak to explain the differences between the models. Our results rather point to an overestimation of SO2 emissions, in particular, close to the surface in Chinese urban areas. However, we also identify a clear underestimation of aerosol concentrations over northern India, suggesting that the rapid recent growth of emissions in India, as well as their spatial extension, is underestimated in emission inventories. Model deficiencies in the representation of pollution accumulation due to the Indian monsoon may also be playing a role. Comparison with vertical aerosol lidar measurements highlights a general underestimation of scattering aerosols in the boundary layer associated with overestimation in the free troposphere pointing to modelled aerosol lifetimes that are too long. This is likely linked to too strong vertical transport and/or insufficient deposition efficiency during transport or export from the boundary layer, rather than chemical processing (in the case of sulphate aerosols). Underestimation of sulphate in the boundary layer implies potentially large errors in simulated aerosol-cloud interactions, via impacts on boundary-layer clouds.

This evaluation has important implications for accurate assessment of air pollutants on regional air quality and global climate based on global model calculations. Ideally, models should be run at higher resolution over source regions to better simulate urban-rural pollutant gradients and/or chemical regimes, and also to better resolve pollutant processing and loss by wet deposition as well as vertical transport. Discrepancies in vertical distributions require further quantification and improvement since these are a key factor in the determination of radiative forcing from short-lived pollutants.
BibTeX:
@article{Quennehen2016,
  author = {Quennehen, B. and Raut, J.-C. and Law, K.S. and Daskalakis, N. and Ancellet, G. and Clerbaux, C. and Kim, S.-W. and Lund, M.T. and Myhre, G. and Olivié, D.J.L. and Safieddine, S. and Skeie, R.B. and Thomas, J.L. and Tsyro, S. and Bazureau, A. and Bellouin, N. and Hu, M. and Kanakidou, M. and Klimont, Z. and Kupiainen, K. and Myriokefalitakis, S. and Quaas, J. and Rumbold, S.T. and Schulz, M. and Cherian, R. and Shimizu, A. and Wang, J. and Yoon, S.-C. and Zhu, T.},
  title = {Multi-model evaluation of short-lived pollutant distributions over east Asia during summer 2008},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {10765-10792},
  doi = {10.5194/acp-16-10765-2016}
}
Abstract: NOMAD (Nadir and Occultation for MArs Discovery) is one of the four instruments on board the ExoMars Trace Gas Orbiter, scheduled for launch in March 2016. It consists of a suite of three high-resolution spectrometers - SO (Solar Occultation), LNO (Limb, Nadir and Occultation) and UVIS (Ultraviolet and Visible Spectrometer). Based upon the characteristics of the channels and the values of Signal-to-Noise Ratio obtained from radiometric models discussed in (Vandaele et al., 2015a, 2015b; Thomas et al., 2016), the expected performances of the instrument in terms of sensitivity to detection have been investigated. The analysis led to the determination of detection limits for 18 molecules, namely CO, H2O, HDO, C2H2, C2H4, C2H6, H2CO, CH4, SO2, H2S, HCl, HCN, HO2, NH3, N2O, NO2, OCS, O3. NOMAD should have the ability to measure methane concentrations < 25 parts per trillion (ppt) in solar occultation mode, and 11 parts per billion in nadir mode. Occultation detections as low as 10 ppt could be made if spectra are averaged (Drummond et al., 2011). Results have been obtained for all three channels in nadir and in solar occultation. © 2016 The Authors. Published by Elsevier Ltd.
BibTeX:
@article{Robert2016,
  author = {Robert, S. and Vandaele, A.C. and Thomas, I. and Willame, Y. and Daerden, F. and Delanoye, S. and Depiesse, C. and Drummond, R. and Neefs, E. and Neary, L. and Ristic, B. and Mason, J. and Lopez-Moreno, J.-J. and Rodriguez-Gomez, J. and Patel, M.R. and Bellucci, G. and Vandaele, A.C. and Lopez Moreno, J.J. and Bellucci, G. and Patel, M. and Allen, M. and Altieri, F. and Aoki, S. and Bolsée, D. and Clancy, T. and Cloutis, E. and Daerden, F. and Depiesse, C. and Fedorova, A. and Formisano, V. and Funke, B. and Fussen, D. and Garcia-Comas, M. and Geminale, A. and Gérard, J.-C. and Gillotay, D. and Giuranna, M. and Gonzalez-Galindo, F. and Ignatiev, N. and Kaminski, J. and Karatekin, O. and Kasaba, Y. and Lefèvre, F. and Lewis, S. and López-Puertas, M. and López-Valverde, M. and Mahieux, A. and Mason, J. and McConnell, J. and Mumma, M. and Neary, L. and Neefs, E. and Novak, R. and Renotte, E. and Robert, S. and Sindoni, G. and Smith, M. and Thomas, I.R. and Trokhimovskiy, A. and Vander Auwera, J. and Villanueva, G. and Viscardy, S. and Whiteway, J. and Willame, Y. and Wilquet, V. and Wolff, M. and Alonso-Rodrigo, G. and Aparicio Del Moral, B. and Barzin, P. and Ben Moussa, A. and Berkenbosch, S. and Biondi, D. and Bonnewijn, S. and Candini, G. and Clairquin, R. and Cubas, J. and Delanoye, S. and Giordanengo, B. and Gissot, S. and Gomez, A. and Zafra, J.-J. and Leese, M. and Maes, J. and Mazy, E. and Mazzoli, A. and Meseguer, J. and Morales, R. and Orban, A. and Pastor-Morales, M. and Perez-Grande, I. and Ristic, B. and Rodriguez-Gomez, J. and Saggin, B. and Samain, V. and Sanz Andres, A. and Sanz, R. and Simar, J.-F. and Thibert, T.},
  title = {Expected performances of the NOMAD/ExoMars instrument},
  journal = {Planetary and Space Science},
  year = {2016},
  volume = {124},
  pages = {94-104},
  doi = {10.1016/j.pss.2016.03.003}
}
Abstract: Knowing the spatial and seasonal distributions of nitric acid (HNO3/ around the globe is of great interest and allows us to comprehend the processes regulating stratospheric ozone, especially in the polar regions. Due to its unprecedented spatial and temporal sampling, the nadir-viewing Infrared Atmospheric Sounding Interferometer (IASI) is capable of sounding the atmosphere twice a day globally, with good spectral resolution and low noise. With the Fast Optimal Retrievals on Layers for IASI (FORLI) algorithm, we are retrieving, in near real time, columns as well as vertical profiles of several atmospheric species, among which is HNO3. We present in this paper the first characterization of the FORLI-HNO3 profile products, in terms of vertical sensitivity and error budgets. We show that the sensitivity of IASI to HNO3 is highest in the lower stratosphere (10-20 km), where the largest amounts of HNO3 are found, but that the vertical sensitivity of IASI only allows one level of information on the profile (degrees of freedom for signal, DOFS; ∼1). The sensitivity near the surface is negligible in most cases, and for this reason, a partial column (5-35 km) is used for the analyses. Both vertical profiles and partial columns are compared to FTIR ground-based measurements from the Network for the Detection of Atmospheric Composition Change (NDACC) to characterize the accuracy and precision of the FORLI-HNO3 product. The profile validation is conducted through the smoothing of the raw FTIR profiles by the IASI averaging kernels and gives good results, with a slight overestimation of IASI measurements in the upper troposphere/lower stratosphere (UTLS) at the six chosen stations (Thule, Kiruna, Jungfraujoch, Izaña, Lauder and Arrival Heights). The validation of the partial columns (5-35 km) is also conclusive with a mean correlation of 0.93 between IASI and the FTIR measurements. An initial survey of the HNO3 spatial and seasonal variabilities obtained from IASI measurements for a 1-year (2011) data set shows that the expected latitudinal gradient of concentrations from low to high latitudes and the large seasonal variability in polar regions (cycle amplitude around 30% of the seasonal signal, peak to peak) are well represented by IASI data. © Author(s) 2016.
BibTeX:
@article{Ronsmans2016,
  author = {Ronsmans, G. and Langerock, B. and Wespes, C. and Hannigan, J.W. and Hase, F. and Kerzenmacher, T. and Mahieu, E. and Schneider, M. and Smale, D. and Hurtmans, D. and De Mazière, M. and Clerbaux, C. and Coheur, P.-F.},
  title = {First characterization and validation of FORLI-HNO3 vertical profiles retrieved from IASI/Metop},
  journal = {Atmospheric Measurement Techniques},
  year = {2016},
  volume = {9},
  pages = {4783-4801},
  doi = {10.5194/amt-9-4783-2016}
}
Abstract: Satellite measurements from the thermal Infrared Atmospheric Sounding Interferometer (IASI), aircraft data from the MOZAIC/IAGOS project, as well as observations from ground-based stations, are used to assess the tropospheric ozone (O3) variability during the East Asian Summer Monsoon (EASM). Six years 2008-2013 of IASI data analysis reveals the ability of the instrument to detect the onset and the progression of the monsoon seen by a decrease in the tropospheric 0-6km O3 column due to the EASM, and to reproduce this decrease from one year to the other. The year-to-year variability is found to be mainly dependent on meteorology. Focusing on the period of May-August 2011, taken as an example year, IASI data show clear inverse relationship between tropospheric 0-6km O3 on one hand and meteorological parameters such as cloud cover, relative humidity and wind speed, on the other hand. Aircraft data from the MOZAIC/IAGOS project for the EASM of 2008-2013 are used to validate the IASI data and to assess the effect of the monsoon on the vertical distribution of the tropospheric O3 at different locations. Results show good agreement with a correlation coefficient of 0.73 (12%) between the 0-6km O3 column derived from IASI and aircraft data. IASI captures very well the inter-annual variation of tropospheric O3 observed by the aircraft data over the studied domain. Analysis of vertical profiles of the aircraft data shows a decrease in the tropospheric O3 that is more important in the free troposphere than in the boundary layer and at 10-20°N than elsewhere. Ground station data at different locations in India and China show a spatiotemporal dependence on meteorology during the monsoon, with a decrease up to 22ppbv in Hyderabad, and up to 5ppbv in the North China Plain. © Author(s) 2016.
BibTeX:
@article{Safieddine2016,
  author = {Safieddine, S. and Boynard, A. and Hao, N. and Huang, F. and Wang, L. and Ji, D. and Barret, B. and Ghude, S.D. and Coheur, P.-F. and Hurtmans, D. and Clerbaux, C.},
  title = {Tropospheric ozone variability during the East Asian summer monsoon as observed by satellite (IASI), aircraft (MOZAIC) and ground stations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {10489-10500},
  doi = {10.5194/acp-16-10489-2016}
}
Abstract: The variability of atmospheric ammonia (NH3), emitted largely from agricultural sources, is an important factor when considering how inorganic fine particulate matter (PM2.5) concentrations and nitrogen cycling are changing over the United States. This study combines new observations of ammonia concentration from the surface, aboard aircraft, and retrieved by satellite to both evaluate the simulation of ammonia in a chemical transport model (GEOS-Chem) and identify which processes control the variability of these concentrations over a 5-year period (2008-2012). We find that the model generally underrepresents the ammonia concentration near large source regions (by 26% at surface sites) and fails to reproduce the extent of interannual variability observed at the surface during the summer (JJA). Variability in the base simulation surface ammonia concentration is dominated by meteorology (64%) as compared to reductions in SO2 and NOx emissions imposed by regulation (32%) over this period. Introduction of year-to-year varying ammonia emissions based on animal population, fertilizer application, and meteorologically driven volatilization does not substantially improve the model comparison with observed ammonia concentrations, and these ammonia emissions changes have little effect on the simulated ammonia concentration variability compared to those caused by the variability of meteorology and acid-precursor emissions. There is also little effect on the PM2.5 concentration due to ammonia emissions variability in the summer when gas-phase changes are favored, but variability in wintertime emissions, as well as in early spring and late fall, will have a larger impact on PM2.5 formation. This work highlights the need for continued improvement in both satellite-based and in situ ammonia measurements to better constrain the magnitude and impacts of spatial and temporal variability in ammonia concentrations. © 2016 The Author(s).
BibTeX:
@article{Schiferl2016,
  author = {Schiferl, L.D. and Heald, C.L. and Damme, M.V. and Clarisse, L. and Clerbaux, C. and Coheur, P.F. and Nowak, J.B. and Neuman, J.A. and Herndon, S.C. and Roscioli, J.R. and Eilerman, S.J.},
  title = {Interannual variability of ammonia concentrations over the United States: Sources and implications},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {12305-12328},
  doi = {10.5194/acp-16-12305-2016}
}
Abstract: The large-scale burning of crop residues in the North China Plain (NCP), one of the most densely populated world regions, was recently recognized to cause severe air pollution and harmful health effects. A reliable quantification of the magnitude of these fires is needed to assess regional air quality. Here, we use an eight-year record (2005-2012) of formaldehyde measurements from space to constrain the emissions of volatile organic compounds (VOCs) in this region. Using inverse modelling, we derive that satellite-based post-harvest burning fluxes are, on average, at least a factor of 2 higher than state-of-the-art bottom-up statistical estimates, although with significant interannual variability. Crop burning is calculated to cause important increases in surface ozone (+7%) and fine aerosol concentrations (+18%) in the North China Plain in June. The impact of crop fires is also found in satellite observations of other species, glyoxal, nitrogen dioxide and methanol, and we show that those measurements validate the magnitude of the top-down fluxes. Our study indicates that the top-down crop burning fluxes of VOCs in June exceed by almost a factor of 2 the combined emissions from other anthropogenic activities in this region, underscoring the need for targeted actions towards changes in agricultural management practices. © 2016 The Author(s).
BibTeX:
@article{Stavrakou2016,
  author = {Stavrakou, T. and Müller, J.-F. and Bauwens, M. and De Smedt, I. and Lerot, C. and Van Roozendael, M. and Coheur, P.-F. and Clerbaux, C. and Boersma, K.F. and Van Der, A.R. and Song, Y.},
  title = {Substantial Underestimation of Post-Harvest Burning Emissions in the North China Plain Revealed by Multi-Species Space Observations},
  journal = {Scientific Reports},
  year = {2016},
  volume = {6},
  article number = {32307},
  doi = {10.1038/srep32307}
}
Abstract: This paper studies the seasonal variation of surface and column CO at three different sites (Paris, Jungfraujoch and Wollongong), with an emphasis on establishing a link between the CO vertical distribution and the nature of CO emission sources. We find the first evidence of a time lag between surface and free tropospheric CO seasonal variations in the Northern Hemisphere. The CO seasonal variability obtained from the total columns and free tropospheric partial columns shows a maximum around March-April and a minimum around September-October in the Northern Hemisphere (Paris and Jungfraujoch). In the Southern Hemisphere (Wollongong) this seasonal variability is shifted by about 6 months. Satellite observations by the IASI-MetOp (Infrared Atmospheric Sounding Interferometer) and MOPITT (Measurements Of Pollution In The Troposphere) instruments confirm this seasonality. Ground-based FTIR (Fourier transform infrared) measurements provide useful complementary information due to good sensitivity in the boundary layer. In situ surface measurements of CO volume mixing ratios at the Paris and Jungfraujoch sites reveal a time lag of the near-surface seasonal variability of about 2 months with respect to the total column variability at the same sites. The chemical transport model GEOS-Chem (Goddard Earth Observing System chemical transport model) is employed to interpret our observations. GEOS-Chem sensitivity runs identify the emission sources influencing the seasonal variation of CO. At both Paris and Jungfraujoch, the surface seasonality is mainly driven by anthropogenic emissions, while the total column seasonality is also controlled by air masses transported from distant sources. At Wollongong, where the CO seasonality is mainly affected by biomass burning, no time shift is observed between surface measurements and total column data. © Author(s) 2016. CC Attribution 3.0 License.
BibTeX:
@article{Te2016,
  author = {Té, Y. and Jeseck, P. and Franco, B. and Mahieu, E. and Jones, N. and Paton-Walsh, C. and Griffith, D.W.T. and Buchholz, R.R. and Hadji-Lazaro, J. and Hurtmans, D. and Janssen, C.},
  title = {Seasonal variability of surface and column carbon monoxide over the megacity Paris, high-altitude Jungfraujoch and Southern Hemispheric Wollongong stations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {10911-10925},
  doi = {10.5194/acp-16-10911-2016}
}
Abstract: NOMAD is a suite of three spectrometers that will be launched in 2016 as part of the joint ESA-Roscosmos ExoMars Trace Gas Orbiter mission. The instrument contains three channels that cover the IR and UV spectral ranges and can perform solar occultation, nadir and limb observations, to detect and map a wide variety of Martian atmospheric gases and trace species. Part I of this work described the models of the UVIS channel; in this second part, we present the optical models representing the two IR channels, SO (Solar Occultation) and LNO (Limb, Nadir and Occultation), and use them to determine signal to noise ratios (SNRs) for many expected observational cases. In solar occultation mode, both the SO and LNO channel exhibit very high SNRs >5000. SNRs of around 100 were found for the LNO channel in nadir mode, depending on the atmospheric conditions, Martian surface properties, and observation geometry. © 2016 Optical Society of America.
BibTeX:
@article{Thomas2016,
  author = {Thomas, I.R. and Vandaele, A.C. and Robert, S. and Neefs, E. and Drummond, R. and Daerden, F. and Delanoye, S. and Ristic, B. and Berkenbosch, S. and Clairquin, R. and Maes, J. and Bonnewijn, S. and Depiesse, C. and Mahieux, A. and Trompet, L. and Neary, L. and Willame, Y. and Wilquet, V. and Nevejans, D. and Aballea, L. and Moelans, W. and De Vos, L. and Lesschaeve, S. and Van Vooren, N. and Lopez-Moreno, J.-J. and Patel, M.R. and Bellucci, G. and Allen, M. and Altieri, F. and Aoki, S. and Bolsée, D. and Clancy, T. and Cloutis, E. and Fedorova, A. and Formisano, V. and Funke, B. and Fussen, D. and Garcia-Comas, M. and Geminale, A. and Gérard, J.-C. and Gillotay, D. and Giuranna, M. and Gonzalez-Galindo, F. and Ignatiev, N. and Kaminski, J. and Karatekin, O. and Kasaba, Y. and Lefèvre, F. and Lewis, S. and López-Puertas, M. and López-Valverde, M. and Mason, J. and McConnell, J. and Mumma, M. and Novak, R. and Renotte, E. and Sindoni, G. and Smith, M. and Trokhimovsky, S. and Vander Auwera, J. and Villanueva, G. and Whiteway, J. and Wolff, M. and Alonso-Rodrigo, G. and Aparicio Del Moral, B. and Barzin, P. and BenMoussa, A. and Biondi, D. and Candini, G.P. and Cubas, J. and Giordanengo, B. and Gissot, S. and Gomez, A. and Zafra, J.-J. and Leese, M. and Mazy, E. and Mazzoli, A. and Meseguer, J. and Morales, R. and Orban, A. and Pastor-Morales, M.D.C. and Perez-Grande, I. and Rodriguez-Gomez, J. and Saggin, B. and Samain, V. and Sanz Andres, A. and Sanz, R. and Simar, J.-F. and Thibert, T.},
  title = {Optical and radiometric models of the NOMAD instrument Part II: The infrared channels - SO and LNO},
  journal = {Optics Express},
  year = {2016},
  volume = {24},
  pages = {3790-3805},
  doi = {10.1364/OE.24.003790}
}
Abstract: Transmission spectra in the fundamental bands of H2 and N2 gas inside the pores of a silica aerogel sample were recorded at room temperature and for several pressures using a Fourier transform spectrometer. They first show that, as the absorption is proportional to the pressure, it is due to the interactions of the molecules with the inner surfaces of the pores and not to the dipole induced during gas-phase molecule-molecule collisions. Furthermore, the analysis of the widths and areas of the observed absorption structures indicate that, for the considered aerogel sample, most of the absorption is likely due to "free" molecules moving within the pores with a weak contribution of adsorbed molecules. © 2016 Elsevier Ltd.
BibTeX:
@article{VanderAuwera2016,
  author = {Vander Auwera, J. and Boulet, C. and Carré, Y. and Kocon, L. and Hartmann, J.-M.},
  title = {Confinement-induced infrared absorption by H2 and N2 gases in a porous silica aerogel},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2016},
  volume = {182},
  pages = {193-198},
  doi = {10.1016/j.jqsrt.2016.05.032}
}
Abstract: Background About 90% of drugs fail in clinical development. The question is whether trials fail because of insufficient efficacy of the new treatment, or rather because of poor trial design that is unable to detect the true efficacy. The variance of the measured endpoints is a major, largely underestimated source of uncertainty in clinical trial design, particularly in acute viral infections. We use a clinical trial simulator to demonstrate how a thorough consideration of the variability inherent in clinical trials of novel therapies for acute viral infections can improve trial design. Methods and Findings We developed a clinical trial simulator to analyse the impact of three different types of variation on the outcome of a challenge study of influenza treatments for infected patients, including individual patient variability in the response to the drug, the variance of the measurement procedure, and the variance of the lower limit of quantification of endpoint measurements. In addition, we investigated the impact of protocol variation on clinical trial outcome. We found that the greatest source of variance was inter-individual variability in the natural course of infection. Running a larger phase II study can save up to $38 million, if an unlikely to succeed phase III trial is avoided. In addition, low-sensitivity viral load assays can lead to falsely negative trial outcomes. Conclusions Due to high inter-individual variability in natural infection, the most important variable in clinical trial design for challenge studies of potential novel influenza treatments is the number of participants. 100 participants are preferable over 50. Using more sensitive viral load assays increases the probability of a positive trial outcome, but may in some circumstances lead to false positive outcomes. Clinical trial simulations are powerful tools to identify the most important sources of variance in clinical trials and thereby help improve trial design. © 2016 Vegvari et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
BibTeX:
@article{Vegvari2016,
  author = {Vegvari, C. and Cauët, E. and Hadjichrysanthou, C. and Lawrence, E. and Weverling, G.-J. and De Wolf, F. and Anderson, R.M.},
  title = {Using clinical trial simulators to analyse the sources of variance in clinical trials of novel therapies for acute viral infections},
  journal = {PLoS ONE},
  year = {2016},
  volume = {11},
  article number = {e0156622},
  doi = {10.1371/journal.pone.0156622}
}
Abstract: Acute viral infections pose many practical challenges for the accurate assessment of the impact of novel therapies on viral growth and decay. Using the example of influenza A, we illustrate how the measurement of infection-related quantities that determine the dynamics of viral load within the human host, can inform investigators on the course and severity of infection and the efficacy of a novel treatment. We estimated the values of key infection-related quantities that determine the course of natural infection from viral load data, using Markov Chain Monte Carlo methods. The data were placebo group viral load measurements collected during volunteer challenge studies, conducted by Roche, as part of the oseltamivir trials. We calculated the values of the quantities for each patient and the correlations between the quantities, symptom severity and body temperature. The greatest variation among individuals occurred in the viral load peak and area under the viral load curve. Total symptom severity correlated positively with the basic reproductive number. The most sensitive endpoint for therapeutic trials with the goal to cure patients is the duration of infection. We suggest laboratory experiments to obtain more precise estimates of virological quantities that can supplement clinical endpoint measurements. © 2016 Vegvari et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
BibTeX:
@article{Vegvari2016a,
  author = {Vegvari, C. and Hadjichrysanthou, C. and Cauët, E. and Lawrence, E. and Cori, A. and De Wolf, F. and Anderson, R.M.},
  title = {How can viral dynamics models inform endpoint measures in clinical trials of therapies for acute viral infections?},
  journal = {PLoS ONE},
  year = {2016},
  volume = {11},
  article number = {e0158237},
  doi = {10.1371/journal.pone.0158237}
}
Abstract: In this paper, we assess how daily ozone (O3) measurements from the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-A platform can contribute to the analyses of the processes driving O3 variability in the troposphere and the stratosphere and, in the future, to the monitoring of long-term trends. The temporal evolution of O3 during the first 6 years of IASI (2008-2013) operation is investigated with multivariate regressions separately in four different layers (ground-300, 300-150, 150-25, 25-3ĝ€hPa), by adjusting to the daily time series averaged in 20° zonal bands, seasonal and linear trend terms along with important geophysical drivers of O3 variation (e.g. solar flux, quasi-biennial oscillation (QBO)). The regression model is shown to perform generally very well with a strong dominance of the annual harmonic terms and significant contributions from O3 drivers, in particular in the equatorial region where the QBO and the solar flux contribution dominate. More particularly, despite the short period of the IASI data set available up to now, two noticeable statistically significant apparent trends are inferred from the daily IASI measurements: a positive trend in the upper stratosphere (e.g. 1.74ĝ€±ĝ€0.77ĝ€DUĝ€yearĝ'1 between 30 and 50°ĝ€S), which is consistent with other studies suggesting a turnaround for stratospheric O3 recovery, and a negative trend in the troposphere at the mid-latitudes and high northern latitudes (e.g. ĝ'0.26ĝ€±ĝ€0.11ĝ€DUĝ€yearĝ'1 between 30 and 50°ĝ€N), especially during summer and probably linked to the impact of decreasing ozone precursor emissions. The impact of the high temporal sampling of IASI on the uncertainty in the determination of O3 trend has been further explored by performing multivariate regressions on IASI monthly averages and on ground-based Fourier transform infrared (FTIR) measurements. © Author(s) 2016. CC Attribution 3.0 License.
BibTeX:
@article{Wespes2016,
  author = {Wespes, C. and Hurtmans, D. and K Emmons, L. and Safieddine, S. and Clerbaux, C. and Edwards, D.P. and Coheur, P.-F.},
  title = {Ozone variability in the troposphere and the stratosphere from the first 6 years of IASI observations (2008-2013)},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {5721-5743},
  doi = {10.5194/acp-16-5721-2016}
}
Abstract: In this paper, we describe a new flexible and robust NH3 retrieval algorithm from measurements of the Infrared Atmospheric Sounding Interferometer (IASI). The method is based on the calculation of a spectral hyperspectral range index (HRI) and subsequent conversion to NH3 columns via a neural network. It is an extension of the method presented in Van Damme et al. (2014a) who used lookup tables (LUT) for the radiance-concentration conversion. The new method inherits the advantages of the LUT-based method while providing several significant improvements. These include the following: (1) Complete temperature and humidity vertical profiles can be accounted for. (2) Third-party NH3 vertical profile information can be used. (3) Reported positive biases of LUT retrieval are reduced, and finally (4) a full measurement uncertainty characterization is provided. A running theme in this study, related to item (2), is the importance of the assumed vertical NH3 profile. We demonstrate the advantages of allowing variable profile shapes in the retrieval. As an example, we analyze how the retrievals change when all NH3 is assumed to be confined to the boundary layer. We analyze different averaging procedures in use for NH3 in the literature, introduced to cope with the variable measurement sensitivity and derive global averaged distributions for the year 2013. A comparison with a GEOS-Chem modeled global distribution is also presented, showing a general good correspondence (within ±3 × 1015 molecules.cm−2) over most of the Northern Hemisphere. However, IASI finds mean columns about 1–1.5 × 1016 molecules.cm−2 (∼50–60%) lower than GEOS-Chem for India and the North China plain. ©2016. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Whitburn2016,
  author = {Whitburn, S. and Van Damme, M. and Clarisse, L. and Bauduin, S. and Heald, C.L. and Hadji-Lazaro, J. and Hurtmans, D. and Zondlo, M.A. and Clerbaux, C. and Coheur, P.-F.},
  title = {A flexible and robust neural network IASI-NH3 retrieval algorithm},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2016},
  volume = {121},
  pages = {6581-6599},
  doi = {10.1002/2016JD024828}
}
Abstract: The semiclassical formalism of Robert and Bonamy is used to calculate the linewidths of rovibrational transitions of ammonia in collision with argon. Two accurate ab initio potential energy surfaces (PES) have been applied to model the NH3-Ar interactions. In this work and contrary to our previous calculations, the transitions with ΔK = ±3n (n integer) have been introduced into the expressions of the differential collision cross section S(b). Comparisons with previous theoretical and experimental studies are reported. A detailed analysis of the contribution of the various anisotropic components of the PES shows that the induced ΔK = ±3 transitions play a crucial role. Calculations performed in the ν4 and ν1 vibrational bands of NH3 are in good agreement with the experimental data and correct dependences of the broadening coefficients with the rotational quantum numbers J and K are obtained. © 2015 Published by Elsevier Inc.
BibTeX:
@article{Ayari2015,
  author = {Ayari, C. and Loreau, J. and Dhib, M. and Daussy, C. and Aroui, H.},
  title = {Semiclassical line broadening calculations using an ab initio potential. Application to NH3 perturbed by argon},
  journal = {Journal of Molecular Spectroscopy},
  year = {2015},
  volume = {318},
  pages = {46-52},
  doi = {10.1016/j.jms.2015.09.011}
}
Abstract: Among the atmospheric emission sources, wildfires are episodic events characterized by large spatial and temporal variability. Therefore, accurate information on gaseous and aerosol emissions from fires for specific regions and seasons is critical for air quality forecasts. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) in geostationary orbit provides fire observations over Africa and the Mediterranean with a temporal resolution of 15 min. It thus resolves the complete fire life cycle and captures the fires' peak intensities, which is not possible in Moderate Resolution Imaging Spectroradiometer (MODIS) fire emission inventories like the Global Fire Assimilation System (GFAS). We evaluate two different operational fire radiative power (FRP) products derived from SEVIRI, by studying a large forest fire in Antalya, Turkey, in July-August 2008. The EUMETSAT Land Surface Analysis Satellite Applications Facility (LSA SAF) has higher FRP values during the fire episode than the Wildfire Automated Biomass Burning Algorithm (WF-ABBA). It is also in better agreement with the co-located, gridded MODIS FRP. Both products miss small fires that frequently occur in the region and are detected by MODIS. Emissions are derived from the FRP products. They are used along-side GFAS emissions in smoke plume simulations with the Weather Research and Forecasting (WRF) model and the Community Multiscale Air Quality (CMAQ) model. In comparisons with MODIS aerosol optical thickness (AOT) and Infrared Atmospheric Sounding Interferometer (IASI), CO and NH3 observations show that including the diurnal variability of fire emissions improves the spatial distribution and peak concentrations of the simulated smoke plumes associated with this large fire. They also show a large discrepancy between the currently available operational FRP products, with the LSA SAF being the most appropriate. © Author(s) 2015.
BibTeX:
@article{Baldassarre2015,
  author = {Baldassarre, G. and Pozzoli, L. and Schmidt, C.C. and Unal, A. and Kindap, T. and Menzel, W.P. and Whitburn, S. and Coheur, P.-F. and Kavgaci, A. and Kaiser, J.W.},
  title = {Using SEVIRI fire observations to drive smoke plumes in the CMAQ air quality model: A case study over Antalya in 2008},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {8539-8558},
  doi = {10.5194/acp-15-8539-2015}
}
Abstract: We show the results and evaluation with independent measurements from assimilating both MOPITT (Measurements Of Pollution In The Troposphere) and IASI (Infrared Atmospheric Sounding Interferometer) retrieved profiles into the Community Earth System Model (CESM). We used the Data Assimilation Research Testbed ensemble Kalman filter technique, with the full atmospheric chemistry CESM component Community Atmospheric Model with Chemistry. We first discuss the methodology and evaluation of the current data assimilation system with coupled meteorology and chemistry data assimilation. The different capabilities of MOPITT and IASI retrievals are highlighted, with particular attention to instrument vertical sensitivity and coverage and how these impact the analyses. MOPITT and IASI CO retrievals mostly constrain the CO fields close to the main anthropogenic, biogenic, and biomass burning CO sources. In the case of IASI CO assimilation, we also observe constraints on CO far from the sources. During the simulation time period (June and July 2008), CO assimilation of both instruments strongly improves the atmospheric CO state as compared to independent observations, with the higher spatial coverage of IASI providing better results on the global scale. However, the enhanced sensitivity of multispectral MOPITT observations to near surface CO over the main source regions provides synergistic effects at regional scales. ©2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Barre2015,
  author = {Barré, J. and Gaubert, B. and Arellano, A.F.J. and Worden, H.M. and Edwards, D.P. and Deeter, M.N. and Anderson, J.L. and Raeder, K. and Collins, N. and Tilmes, S. and Francis, G. and Clerbaux, C. and Emmons, L.K. and Pfister, G.G. and Coheur, P.-F. and Hurtmans, D.},
  title = {Assessing the impacts of assimilating IASI and MOPITT CO retrievals using CESM-CAM-chem and DART},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2015},
  volume = {120},
  pages = {10501-10529},
  doi = {10.1002/2015JD023467}
}
BibTeX:
@article{Berger2015,
  author = {Berger, G. and Gelbcke, M. and Cauët, E. and Luhmer, M. and Nève, J. and Dufrasne, F.},
  title = {Erratum:Corrigendum to "synthesis of 15N-labeled vicinal diamines through N-activated chiral aziridines: Tools for the NMR study of platinum-based anticancer compounds" (Tetrahedron Letters (2013) 54 (545-548) doi:10.1016/j.tetlet.2014.11.086))},
  journal = {Tetrahedron Letters},
  year = {2015},
  volume = {56},
  pages = {485},
  doi = {10.1016/j.tetlet.2014.11.086}
}
Abstract: Sulfur-rich degassing, which is mostly composed of sulfur dioxide (SO2), plays a major role in the overall impact of volcanism on the atmosphere and climate. The accurate assessment of this impact is currently hampered by the poor knowledge of volcanic SO2 emissions. Here, using an inversion procedure, we show how assimilating snapshots of the volcanic SO2 load derived from the Infrared Atmospheric Sounding Interferometer (IASI) allows for reconstructing both the flux and altitude of the SO2 emissions with an hourly resolution. For this purpose, the regional chemistry-transport model CHIMERE is used to describe the dispersion of SO2 when released in the atmosphere. As proof of concept, we study the 10 April 2011 eruption of the Etna volcano (Italy), which represents one of the few volcanoes instrumented on the ground for the continuous monitoring of SO2 degassing. We find that the SO2 flux time-series retrieved from satellite imagery using the inverse scheme is in agreement with ground observations during ash-poor phases of the eruption. However, large discrepancies are observed during the ash-rich paroxysmal phase as a result of enhanced plume opacity affecting ground-based ultraviolet (UV) spectroscopic retrievals. As a consequence, the SO2 emission rate derived from the ground is underestimated by almost one order of magnitude. Altitudes of the SO2 emissions predicted by the inverse scheme are validated against an RGB image of the Moderate Resolution Imaging Spectroradiometer (MODIS) capturing the near-source atmospheric pathways followed by Etna plumes, in combination with forward trajectories from the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. At a large distance from the source, modelled SO2 altitudes are compared with independent information on the volcanic cloud height. We find that the altitude predicted by the inverse scheme is in agreement with snapshots of the SO2 height retrieved from recent algorithms exploiting the high spectral resolution of IASI. The validity of the modelled SO2 altitude is further confirmed by the detection of a layer of particles at the same altitude by the spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). Analysis of CALIOP colour and depolarization ratios suggests that these particles consist of sulfate aerosols formed from precursory volcanic SO2. The reconstruction of emission altitude, through inversion procedures which assimilate volcanic SO2 column amounts, requires specific meteorological conditions, especially sufficient wind shear so that gas parcels emitted at different altitudes follow distinct trajectories. We consequently explore the possibility and limits of assimilating in inverse schemes infrared (IR) imagery of the volcanic SO2 cloud altitude which will render the inversion procedure independent of the wind shear prerequisite. © Author(s) 2015.
BibTeX:
@article{Boichu2015,
  author = {Boichu, M. and Clarisse, L. and Péré, J.-C. and Herbin, H. and Goloub, P. and Thieuleux, F. and Ducos, F. and Clerbaux, C. and Tanré, D.},
  title = {Temporal variations of flux and altitude of sulfur dioxide emissions during volcanic eruptions: Implications for long-range dispersal of volcanic clouds},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {8381-8400},
  doi = {10.5194/acp-15-8381-2015}
}
Abstract: Abstract During 7-12 July 2012, extreme moist and warm conditions occurred over Greenland, leading to widespread surface melt. To investigate the physical processes during the atmospheric moisture transport of this event, we study the water vapor isotopic composition using surface in situ observations in Bermuda Island, South Greenland coast (Ivittuut), and northwest Greenland ice sheet (NEEM), as well as remote sensing observations (Infrared Atmospheric Sounding Interferometer (IASI) instrument on board MetOp-A), depicting propagation of similar surface and midtropospheric humidity and δD signals. Simulations using Lagrangian moisture source diagnostic and water tagging in a regional model showed that Greenland was affected by an atmospheric river transporting moisture from the western subtropical North Atlantic Ocean, which is coherent with observations of snow pit impurities deposited at NEEM. At Ivittuut, surface air temperature, humidity, and δD increases are observed. At NEEM, similar temperature increase is associated with a large and long-lasting ∼100‰δD enrichment and ∼15‰ deuterium excess decrease, thereby reaching Ivittuut level. We assess the simulation of this event in two isotope-enabled atmospheric general circulation models (LMDz-iso and ECHAM5-wiso). LMDz-iso correctly captures the timing of propagation for this event identified in IASI data but depict too gradual variations when compared to surface data. Both models reproduce the surface meteorological and isotopic values during the event but underestimate the background deuterium excess at NEEM. Cloud liquid water content parametrization in LMDz-iso poorly impacts the vapor isotopic composition. Our data demonstrate that during this atmospheric river event the deuterium excess signal is conserved from the moisture source to northwest Greenland. Key Points Water vapor isotopic fingerprint of Greenland summer 2012 atmospheric river Surface and remote sensing observations and models depict similar patterns Strong influence of subtropical North Atlantic moisture with low distillation ©2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Bonne2015,
  author = {Bonne, J.-L. and Steen-Larsen, H.C. and Risi, C. and Werner, M. and Sodemann, H. and Lacour, J.-L. and Fettweis, X. and Cesana, G. and Delmotte, M. and Cattani, O. and Vallelonga, P. and Kjær, H.A. and Clerbaux, C. and Sveinbjörnsdõttir, A.E. and Masson-Delmotte, V.},
  title = {The summer 2012 Greenland heat wave: In situ and remote sensing observations of water vapor isotopic composition during an atmospheric river event},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2015},
  volume = {120},
  pages = {2970-2989},
  doi = {10.1002/2014JD022602}
}
Abstract: The IASI mission flying onboard the MetOp satellites has been providing global observations of the air composition twice a day since 2007. From the atmospheric spectra recorded by the instruments in the thermal infrared spectral range, concentrations of a series of trace gases can be monitored, enhanced levels of pollution can be detected, and particle types can be determined to some extent. This paper recalls the historical context for the IASI remote sensor, reviews its capability to observe some key species for global and regional pollution monitoring, and reports on information services that benefit from the mission. © 2015 Academie des sciences
BibTeX:
@article{Clerbaux2015,
  author = {Clerbaux, C. and Hadji-Lazaro, J. and Turquety, S. and George, M. and Boynard, A. and Pommier, M. and Safieddine, S. and Coheur, P.-F. and Hurtmans, D. and Clarisse, L. and Van Damme, M.},
  title = {Tracking pollutants from space: Eight years of IASI satellite observation},
  journal = {Comptes Rendus - Geoscience},
  year = {2015},
  volume = {347},
  pages = {134-144},
  doi = {10.1016/j.crte.2015.06.001}
}
Abstract: We present a retrieval method for ammonia (NH3) total columns from ground-based Fourier transform infrared (FTIR) observations. Observations from Bremen (53.10° N, 8.85° E), Lauder (45.04° S, 169.68° E), Reúnion (20.9° S, 55.50° E) and Jungfraujoch (46.55° N, 7.98° E) were used to illustrate the capabilities of the method. NH3 mean total columns ranging 3 orders of magnitude were obtained, with higher values at Bremen (mean of 13.47 × 1015 molecules cm-2) and lower values at Jungfraujoch (mean of 0.18 × 1015 molecules cm-2). In conditions with high surface concentrations of ammonia, as in Bremen, it is possible to retrieve information on the vertical gradient, as two layers can be distinguished. The retrieval there is most sensitive to ammonia in the planetary boundary layer, where the trace gas concentration is highest. For conditions with low concentrations, only the total column can be retrieved. Combining the systematic and random errors we have a mean total error of 26 % for all spectra measured at Bremen (number of spectra (N)= 554), 30 % for all spectra from Lauder (N = 2412), 25 % for spectra from Reúnion (N = 1262) and 34 % for spectra measured at Jungfraujoch (N = 2702). The error is dominated by the systematic uncertainties in the spectroscopy parameters. Station-specific seasonal cycles were found to be consistent with known seasonal cycles of the dominant ammonia sources in the station surroundings. The developed retrieval methodology from FTIR instruments provides a new way of obtaining highly time-resolved measurements of ammonia burdens. FTIR-NH3 observations will be useful for understanding the dynamics of ammonia concentrations in the atmosphere and for satellite and model validation. It will also provide additional information to constrain the global ammonia budget. © 2015 Author(s).
BibTeX:
@article{Dammers2015,
  author = {Dammers, E. and Vigouroux, C. and Palm, M. and Mahieu, E. and Warneke, T. and Smale, D. and Langerock, B. and Franco, B. and Van Damme, M. and Schaap, M. and Notholt, J. and Erisman, J.W.},
  title = {Retrieval of ammonia from ground-based FTIR solar spectra},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {12789-12803},
  doi = {10.5194/acp-15-12789-2015}
}
Abstract: The Double Focusing Mass Spectrometer (DFMS), part of the ROSINA instrument package aboard the European Space Agency's Rosetta spacecraft visiting comet 67P/Churyumov-Gerasimenko, experiences minor deformation of the mass peaks in the high resolution spectra acquired for m/Z = 16, 17, and to a lesser extent 18. A numerical deconvolution technique has been developed with a twofold purpose. A first goal is to verify whether the most likely cause of the issue, a lack of stability of one of the electric potentials in the electrostatic analyser, can indeed be held responsible for it. The second goal is to correct for the deformation, in view of the important species located around these masses, and to allow a standard further treatment of the spectra in the automated DFMS data processing chain. © 2015 The Authors. Published by Elsevier B.V.
BibTeX:
@article{DeKeyser2015,
  author = {De Keyser, J. and Dhooghe, F. and Gibbons, A. and Altwegg, K. and Balsiger, H. and Berthelier, J.-J. and Briois, C. and Calmonte, U. and Cessateur, G. and Equeter, E. and Fiethe, B. and Fuselier, S.A. and Gombosi, T.I. and Gunell, H. and Hässig, M. and Le Roy, L. and Maggiolo, R. and Neefs, E. and Rubin, M. and Sémon, T.},
  title = {Correcting peak deformation in Rosetta's ROSINA/DFMS mass spectrometer},
  journal = {International Journal of Mass Spectrometry},
  year = {2015},
  volume = {393},
  pages = {41-51},
  doi = {10.1016/j.ijms.2015.10.010}
}
Abstract: Ozone is an important greenhouse gas in terms of anthropogenic radiative forcing (RF). RF calculations for ozone were until recently entirely model based, and significant discrepancies were reported due to different model characteristics. However, new instantaneous radiative kernels (IRKs) calculated from hyperspectral thermal IR satellites have been able to help adjudicate between different climate model RF calculations. IRKs are defined as the sensitivity of the outgoing longwave radiation (OLR) flux with respect to the ozone vertical distribution in the full 9.6 μm band. Previous methods applied to measurements from the Tropospheric Emission Spectrometer (TES) on Aura rely on an anisotropy approximation for the angular integration. In this paper, we present a more accurate but more computationally expensive method to calculate these kernels. The method of direct integration is based on similar principles to the anisotropy approximation, but it deals more precisely with the integration of the Jacobians. We describe both methods and highlight their differences with respect to the IRKs and the ozone longwave radiative effect (LWRE), i.e., the radiative impact in OLR due to absorption by ozone, for both tropospheric and total columns, from measurements of the Infrared Atmospheric Sounding Interferometer (IASI) onboard MetOp-A. Biases between the two methods vary from -25 to +20 % for the LWRE, depending on the viewing angle. These biases point to the inadequacy of the anisotropy method, especially at nadir, suggesting that the TES-derived LWREs are biased low by around 25 % and that chemistry-climate model OLR biases with respect to TES are underestimated. In this paper we also exploit the sampling performance of IASI to obtain first daily global distributions of the LWRE, for 12 days (the 15th of each month) in 2011, calculated with the direct integration method. We show that the temporal variation of global and latitudinal averages of the LWRE shows patterns which are controlled by changes in the surface temperature and ozone variation due to specific processes, such as the ozone hole in the polar regions and stratospheric intrusions into the troposphere. © Author(s) 2015.
BibTeX:
@article{Doniki2015,
  author = {Doniki, S. and Hurtmans, D. and Clarisse, L. and Clerbaux, C. and Worden, H.M. and Bowman, K.W. and Coheur, P.-F.},
  title = {Instantaneous longwave radiative impact of ozone: An application on IASI/MetOp observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {12971-12987},
  doi = {10.5194/acp-15-12971-2015}
}
Abstract: We present global distributions of C2H2 and hydrogen cyanide (HCN) total columns derived from the Infrared Atmospheric Sounding Interferometer (IASI) for the years 2008-2010. These distributions are obtained with a fast method allowing to retrieve C2H2 abundance globally with a 5 % precision and HCN abundance in the tropical (subtropical) belt with a 10 % (25 %) precision. IASI data are compared for validation purposes with ground-based Fourier transform infrared (FTIR) spectrometer measurements at four selected stations. We show that there is an overall agreement between the ground-based and space measurements with correlation coefficients for daily mean measurements ranging from 0.28 to 0.81, depending on the site. Global C2H2 and subtropical HCN abundances retrieved from IASI spectra show the expected seasonality linked to variations in the anthropogenic emissions and seasonal biomass burning activity, as well as exceptional events, and are in good agreement with previous spaceborne studies. Total columns simulated by the Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4) are compared to the ground-based FTIR measurements at the four selected stations. The model is able to capture the seasonality in the two species in most of the cases, with correlation coefficients for daily mean measurements ranging from 0.50 to 0.86, depending on the site. IASI measurements are also compared to the distributions from MOZART-4. Seasonal cycles observed from satellite data are reasonably well reproduced by the model with correlation coefficients ranging from g'0.31 to 0.93 for C2H2 daily means, and from 0.09 to 0.86 for HCN daily means, depending on the considered region. However, the anthropogenic (biomass burning) emissions used in the model seem to be overestimated (underestimated), and a negative global mean bias of 1 % (16 %) of the model relative to the satellite observations was found for C2H2 (HCN). © Author(s) 2015.
BibTeX:
@article{Duflot2015,
  author = {Duflot, V. and Wespes, C. and Clarisse, L. and Hurtmans, D. and Ngadi, Y. and Jones, N. and Paton-Walsh, C. and Hadji-Lazaro, J. and Vigouroux, C. and De Mazière, M. and Metzger, J.-M. and Mahieu, E. and Servais, C. and Hase, F. and Schneider, M. and Clerbaux, C. and Coheur, P.-F.},
  title = {Acetylene (C2H2) and hydrogen cyanide (HCN) from IASI satellite observations: Global distributions, validation, and comparison with model},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {10509-10527},
  doi = {10.5194/acp-15-10509-2015}
}
Abstract: An overview of the achievements and the current state of knowledge on reactive nitrogen in Europe, focusing on deposition, critical load exceedances, and modeled and measured trends.
BibTeX:
@article{Erisman2015,
  author = {Erisman, J.W. and Dammers, E. and Van Damme, M. and Soudzilovskaia, N. and Schaap, M.},
  title = {Trends in EU nitrogen deposition and impacts on ecosystems},
  journal = {EM: Air and Waste Management Association's Magazine for Environmental Managers},
  year = {2015},
  volume = {65},
  pages = {31-35}
}
Abstract: We have investigated the N2O-HDO molecular complex using ab initio calculations at the CCSD(T)-F12a/aug-cc-pVTZ level of theory and using cavity ring-down spectroscopy to probe an HDO/N2O/Ar supersonic jet around 1.58 m. A single a-type vibrational band was observed, 13 cm-1 redshifted compared to the OH+OD excited band in HDO, and 173 vibration-rotation lines were assigned (Trot ≈ 20 K). A weighted fit of existing microwave and present near infrared (NIR) data was achieved using a standard Watson's Hamiltonian (σ = 1.26), producing ground and excited states rotational constants. The comparison of the former with those calculated ab initio suggests a planar geometry in which the OD rather than the OH bond in water is almost parallel to NNO. The equilibrium geometry and dissociation energy (De = -11.7 kJ/mol) of the water-nitrous oxide complex were calculated. The calculations further demonstrate and allow characterising another minimum, 404 cm-1 (ΔE0) higher in energy. Harmonic vibrational frequencies and dissociation energies, D0, were calculated for various conformers and isotopic forms of the complex, in both minima. The absence of N2O-D2O from dedicated NIR experiments is reported and discussed. © 2014 Taylor & Francis.
BibTeX:
@article{Foeldes2015,
  author = {Földes, T. and Lauzin, C. and Vanfleteren, T. and Herman, M. and Liévin, J. and Didriche, K.},
  title = {High-resolution, near-infrared CW-CRDS, and ab initio investigations of N2O-HDO},
  journal = {Molecular Physics},
  year = {2015},
  volume = {113},
  pages = {473-482},
  doi = {10.1080/00268976.2014.953611}
}
Abstract: Carbon monoxide (CO) is a key atmospheric compound that can be remotely sensed by satellite on the global scale. Fifteen years of continuous observations are now available from the MOPITT/Terra mission (2000 to present). Another 15 and more years of observations will be provided by the IASI/MetOp instrument series (2007-2023 >). In order to study long-term variability and trends, a homogeneous record is required, which is not straightforward as the retrieved quantities are instrument and processing dependent. The present study aims at evaluating the consistency between the CO products derived from the MOPITT and IASI missions, both for total columns and vertical profiles, during a 6-year overlap period (2008-2013). The analysis is performed by first comparing the available 2013 versions of the retrieval algorithms (v5T for MOPITT and v20100815 for IASI), and second using a dedicated reprocessing of MOPITT CO profiles and columns using the same a priori information as the IASI product. MOPITT total columns are generally slightly higher over land (bias ranging from 0 to 13 %) than IASI data. When IASI and MOPITT data are retrieved with the same a priori constraints, correlation coefficients are slightly improved. Large discrepancies (total column bias over 15 %) observed in the Northern Hemisphere during the winter months are reduced by a factor of 2 to 2.5. The detailed analysis of retrieved vertical profiles compared with collocated aircraft data from the MOZAIC-IAGOS network, illustrates the advantages and disadvantages of a constant vs. a variable a priori. On one hand, MOPITT agrees better with the aircraft profiles for observations with persisting high levels of CO throughout the year due to pollution or seasonal fire activity (because the climatology-based a priori is supposed to be closer to the real atmospheric state). On the other hand, IASI performs better when unexpected events leading to high levels of CO occur, due to a larger variability associated with the a priori. © 2015 Author(s).
BibTeX:
@article{George2015,
  author = {George, M. and Clerbaux, C. and Bouarar, I. and Coheur, P.-F. and Deeter, M.N. and Edwards, D.P. and Francis, G. and Gille, J.C. and Hadji-Lazaro, J. and Hurtmans, D. and Inness, A. and Mao, D. and Worden, H.M.},
  title = {An examination of the long-term CO records from MOPITT and IASI: Comparison of retrieval methodology},
  journal = {Atmospheric Measurement Techniques},
  year = {2015},
  volume = {8},
  pages = {4313-4328},
  doi = {10.5194/amt-8-4313-2015}
}
Abstract: We have used continuous-wave cavity ring-down and femto-Fourier transform-cavity-enhanced absorption spectrometers to record the spectrum of the OH-stretching + CH-stretching (ν1 + ν2) combination band in trans-formic acid, with origin close to 6507 cm-1. They, respectively, allowed resolving and simplifying the rotational structure of the band near its origin under jet-cooled conditions (Trot = 10 K) and highlighting the overview of the band under room temperature conditions. The stronger B-type and weaker A-type subbands close to the band origin could be assigned, as well as the main B-type Q branches. The high-resolution analysis was hindered by numerous, severe perturbations. Rotational constants are reported with, however, limited physical meaning. The ν1 + ν2 transition moment is estimated from relative intensities to be 24°away from the principal b-axis of inertia. © 2015 AIP Publishing LLC.
BibTeX:
@article{Golebiowski2015,
  author = {Golebiowski, D. and Földes, T. and Vanfleteren, T. and Herman, M. and Perrin, A.},
  title = {Complementary cavity-enhanced spectrometers to investigate the OH + CH combination band in trans -formic acid},
  journal = {Journal of Chemical Physics},
  year = {2015},
  volume = {143},
  article number = {014201},
  doi = {10.1063/1.4923256}
}
Abstract: Recently there has been a renewed interest in the chemical physics literature of factorization of the position representation eigenfunctions φ of the molecular Schrödinger equation as originally proposed by Hunter in the 1970s. The idea is to represent φ in the form φχ where χ is purely a function of the nuclear coordinates, while φ must depend on both electron and nuclear position variables in the problem. This is a generalization of the approximate factorization originally proposed by Born and Oppenheimer, the hope being that an 'exact' representation of φ can be achieved in this form with φ and χ interpretable as 'electronic' and 'nuclear' wavefunctions respectively. We offer a mathematical analysis of these proposals that identifies ambiguities stemming mainly from the singularities in the Coulomb potential energy. © 2015 IOP Publishing Ltd.
BibTeX:
@article{Jecko2015,
  author = {Jecko, T. and Sutcliffe, B.T. and Woolley, R.G.},
  title = {On factorization of molecular wavefunctions},
  journal = {Journal of Physics A: Mathematical and Theoretical},
  year = {2015},
  volume = {48},
  article number = {445201},
  doi = {10.1088/1751-8113/48/44/445201}
}
Abstract: The Infrared Atmospheric Sounding Interferometer (IASI) flying onboard MetOpA and MetOpB is able to capture fine isotopic variations of the HDO to H2O ratio (δD) in the troposphere. Such observations at the high spatio-temporal resolution of the sounder are of great interest to improve our understanding of the mechanisms controlling humidity in the troposphere. In this study we aim to empirically assess the validity of our error estimation previously evaluated theoretically. To achieve this, we compare IASI δD retrieved profiles with other available profiles of δD, from the TES infrared sounder onboard AURA and from three ground-based FTIR stations produced within the MUSICA project: the NDACC (Network for the Detection of Atmospheric Composition Change) sites Kiruna and Izaña, and the TCCON site Karlsruhe, which in addition to near-infrared TCCON spectra also records mid-infrared spectra. We describe the achievable level of agreement between the different retrievals and show that these theoretical errors are in good agreement with empirical differences. The comparisons are made at different locations from tropical to Arctic latitudes, above sea and above land. Generally IASI and TES are similarly sensitive to δD in the free troposphere which allows one to compare their measurements directly. At tropical latitudes where IASI's sensitivity is lower than that of TES, we show that the agreement improves when taking into account the sensitivity of IASI in the TES retrieval. For the comparison IASI-FTIR only direct comparisons are performed because the sensitivity profiles of the two observing systems do not allow to take into account their differences of sensitivity. We identify a quasi negligible bias in the free troposphere (-3 ‰) between IASI retrieved δD with the TES, which are bias corrected, but important with the ground-based FTIR reaching -47 ‰. We also suggest that model-satellite observation comparisons could be optimized with IASI thanks to its high spatial and temporal sampling. © Author(s) 2015.
BibTeX:
@article{Lacour2015,
  author = {Lacour, J.-L. and Clarisse, L. and Worden, J. and Schneider, M. and Barthlott, S. and Hase, F. and Risi, C. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F.},
  title = {Cross-validation of IASI/MetOp derived tropospheric δd with TES and ground-based FTIR observations},
  journal = {Atmospheric Measurement Techniques},
  year = {2015},
  volume = {8},
  pages = {1447-1466},
  doi = {10.5194/amt-8-1447-2015}
}
Abstract: An update of the former version of the database and software for the calculation of CO2-air absorption coefficients taking line-mixing into account [Lamouroux et al. J Quant Spectrosc Radiat Transf 2010;111:2321] is described. In this new edition, the data sets were constructed using parameters from the 2012 version of the HITRAN database and recent measurements of line-shape parameters. Among other improvements, speed-dependent profiles can now be used if line-mixing is treated within the first order approximation. This new package is tested using laboratory spectra measured in the 2.1μm and 4.3μm spectral regions for various pressures, temperatures and CO2 concentration conditions. Despite improvements at 4.3μm at room temperature, the conclusions on the quality of this update are more ambiguous at low temperature and in the 2.1μm region. Further tests using laboratory and atmospheric spectra are thus required for the evaluation of the performances of this updated package. © 2014 Elsevier Ltd.
BibTeX:
@article{Lamouroux2015,
  author = {Lamouroux, J. and Régalia, L. and Thomas, X. and Vander Auwera, J. and Gamache, R.R. and Hartmann, J.-M.},
  title = {CO2 line-mixing database and software update and its tests in the 2.1μm and 4.3μm regions},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2015},
  volume = {151},
  pages = {88-96},
  doi = {10.1016/j.jqsrt.2014.09.017}
}
Abstract: Ion-pair dissociation of a highly excited molecule is a relaxation process giving rise to emission of anionic and cationic fragments. We present first measurements of ion-pair dissociation of carbon clusters. We found that ion- pair relaxation is an ubiquitous, although very small, relaxation channel common to all sizes and charges of Cq+n species produced in high velocity C+n-He collisions. Quantitative interpretation of measured branching ratios is conducted on the basis of a statistical approach i.e through listing of all possible final states. © Published under licence by IOP Publishing Ltd.
BibTeX:
@article{Launoy2015,
  author = {Launoy, T. and Chabot, M. and Martinet, G. and Pino, T. and Le Padellec, A. and Bouneau, S. and Féraud, G. and Do Thi, N. and Vaeck, N. and Liévin, J. and Loreau, J. and Béroff, K.},
  title = {Ion-pair dissociation of highly excited carbon clusters, size and charge effects},
  journal = {Journal of Physics: Conference Series},
  year = {2015},
  volume = {635},
  article number = {032085},
  doi = {10.1088/1742-6596/635/3/032085}
}
Abstract: Ion pair collisions are an important process in many astrophysical environments. We present ab initio calculations of highly excited states of C2+ and identify the ion pair channel C2+/C-. We use these results to interpret recent experiments on carbon cluster dissociation. © Published under licence by IOP Publishing Ltd.
BibTeX:
@article{Launoy2015a,
  author = {Launoy, T. and Vaeck, N. and Urbain, X. and Liévin, J. and Loreau, J. and Béroff, K. and Chabot, M.},
  title = {On the reactivity of ion pairs into different diatomic systems},
  journal = {Journal of Physics: Conference Series},
  year = {2015},
  volume = {635},
  article number = {022018},
  doi = {10.1088/1742-6596/635/2/022018}
}
Abstract: We present a theoretical study of elastic and rotationally inelastic collisions of NH3 and ND3 with rare gas atoms (He, Ne, Ar, Kr, Xe) at low energy. Quantum close-coupling calculations have been performed for energies between 0.001 and 300 cm-1. We focus on collisions in which NH3 is initially in the upper state of the inversion doublet with j = 1, k = 1, which is the most relevant in an experimental context as it can be trapped electrostatically and Stark-decelerated. We discuss the presence of resonances in the elastic and inelastic cross sections, as well as the trends in the inelastic cross sections along the rare gas series and the differences between NH3 and ND3 as a colliding partner. We also demonstrate the importance of explicitly taking into account the umbrella (inversion) motion of NH3 in order to obtain accurate scattering cross sections at low collision energy. Finally, we investigate the possibility of sympathetic cooling of ammonia using cold or ultracold rare gas atoms. We show that some systems exhibit a large ratio of elastic to inelastic cross sections in the cold regime, which is promising for sympathetic cooling experiments. The close-coupling calculations are based on previously reported ab initio potential energy surfaces for NH3-He and NH3-Ar, as well as on new, four-dimensional, potential energy surfaces for the interaction of ammonia with Ne, Kr, and Xe, which were computed using the coupled-cluster method and large basis sets. We compare the properties of the potential energy surfaces corresponding to the interaction of ammonia with the various rare gas atoms. © 2015 AIP Publishing LLC.
BibTeX:
@article{Loreau2015,
  author = {Loreau, J. and Van Der Avoird, A.},
  title = {Scattering of NH3 and ND3 with rare gas atoms at low collision energy},
  journal = {Journal of Chemical Physics},
  year = {2015},
  volume = {143},
  article number = {184303},
  doi = {10.1063/1.4935259}
}
Abstract: High resolution (0.011cm-1) room temperature (295K) Fourier transform absorption spectra (FTS) of acetylene have been recorded between 7000 and 7500cm-1. Line parameters (positions, intensities and self broadening coefficients) have been measured using a multispectrum treatment of three FTS spectra, recorded at 3.84, 8.04 and 56.6hPa. As a result, a list of 3788 lines was constructed with intensities ranging between about 10-26 and 10-22cm/molecule. Comparison with accurate predictions provided by a global effective operator model (Lyulin OM, Perevalov VI, Teffo JL, Proc. SPIE 2004;5311:134-43) led to the assignment of 2471 of these lines to 12C2H2. The assigned lines belong to 29 12C2H2 bands, 12 of them being newly reported. Spectroscopic parameters of the upper vibrational levels were derived from band-by-band fits of the line positions (typical rms values are on the order of 0.001cm-1). About half of the analyzed bands were found to be affected by rovibrational perturbations. Line parameters obtained in this work were compared with those available for about 350 transitions in the HITRAN 2012 database. The large set of new data will be valuable to refine the parameters of the global effective Hamiltonian and dipole moments of 12C2H2. © 2015 Elsevier Ltd.
BibTeX:
@article{Lyulin2015,
  author = {Lyulin, O.M. and Vander Auwera, J. and Campargue, A.},
  title = {The Fourier transform absorption spectrum of acetylene between 7000 and 7500cm-1},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2015},
  volume = {160},
  pages = {85-93},
  doi = {10.1016/j.jqsrt.2015.03.018}
}
Abstract: We present theoretical studies on the scattering resonances in rotationally inelastic collisions of NH3 and ND3 molecules with H2 molecules. We use the quantum close-coupling method to compute state-to-state integral and differential cross sections for the NH3/ND3-H2 system for collision energies between 5 and 70 cm-1, using a previously reported potential energy surface [Maret et al., Mon. Not. R. Astron. Soc. 399, 425 (2009)]. We identify the resonances as shape or Feshbach resonances. To analyze these, we use an adiabatic bender model, as well as examination at the scattering wave functions and lifetimes. The strength and width of the resonance peaks suggest that they could be observed in a crossed molecular beam experiment involving a Stark-decelerated NH3 beam. © 2015 AIP Publishing LLC.
BibTeX:
@article{Ma2015,
  author = {Ma, Q. and Van Der Avoird, A. and Loreau, J. and Alexander, M.H. and Van De Meerakker, S.Y.T. and Dagdigian, P.J.},
  title = {Resonances in rotationally inelastic scattering of NH3 and ND3 with H2},
  journal = {Journal of Chemical Physics},
  year = {2015},
  volume = {143},
  article number = {044312},
  doi = {10.1063/1.4927074}
}
Abstract: The present work deals with a set of problems in isotope shifts of neutral barium spectral lines. Some well-known transitions (6s21S0-6s6p1,3P1o and 6s21S0-6p23P0) are investigated. Values of the changes in the nuclear mean-square charge radius are deduced from the available experimental isotope shifts using our ab initio electronic factors. The three sets δ r2A,A′ obtained from these lines are consistent with each other. The combination of the available nuclear mean-square radii with our electronic factors for the 6s5d3D1,2-6s6p1P1o transitions produces isotope shift values in conflict with the laser spectroscopy measurements of U. Dammalapati et al. [Eur. Phys. J. D 53, 1 (2009)EPJDF61434-606010.1140/epjd/e2009-00076-x]. © 2015 American Physical Society.
BibTeX:
@article{Naze2015,
  author = {Nazé, C. and Li, J.G. and Godefroid, M.},
  title = {Theoretical isotope shifts in neutral barium},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2015},
  volume = {91},
  article number = {032511},
  doi = {10.1103/PhysRevA.91.032511}
}
BibTeX:
@article{Predoi-Cross2015,
  author = {Predoi-Cross, A. and Liu, W. and Murphy, R. and Povey, C. and Gamache, R. and Laraia, A. and McKellar, A.R.W. and Hurtmans, D. and Devi, V.M.},
  title = {Corrigendum to "Measurement and computations for temperature dependences of self-broadened carbon dioxide transitions in the 30012-00001 and 30013-00001 bands" [J. Quant. Spectrosc. Radiat. Transf., 111 (9) (2010) 1065-1079] doi: 10.1016/j.jqsrt.2010.01.003},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2015},
  volume = {164},
  pages = {256},
  doi = {10.1016/j.jqsrt.2015.06.017}
}
Abstract: Optimal control theory has been employed to populate separately two dark states of the acetylene polyad, Ns = 1 and Nr = 5, by indirect coupling via the ground state. Relevant level energies and transition dipole moments are extracted from the experimental literature. The optimal pulses are rather simple. The evolution of the population is shown for the duration of the control process and also for the field-free evolution that follows the control. One of the dark states appears to be a potential target for realistic experimental investigation because the average population of the Rabi oscillation remains high and decoherence is expected to be weak. © 2015 Taylor and Francis.
BibTeX:
@article{Santos2015a,
  author = {Santos, L. and Iacobellis, N. and Herman, M. and Perry, D.S. and Desouter-Lecomte, M. and Vaeck, N.},
  title = {A test of optimal laser impulsion for controlling population within the N s = 1, N r = 5 polyad of 12C 2H 2},
  journal = {Molecular Physics},
  year = {2015},
  volume = {113},
  pages = {4000-4006},
  doi = {10.1080/00268976.2015.1102980}
}
Abstract: Following a recent proposal of L. Wang and D. Babikov [J. Chem. Phys. 137, 064301 (2012)], we theoretically illustrate the possibility of using the motional states of a Cd+ ion trapped in a slightly anharmonic potential to simulate the single-particle time-dependent Schrödinger equation. The simulated wave packet is discretized on a spatial grid and the grid points are mapped on the ion motional states which define the qubit network. The localization probability at each grid point is obtained from the population in the corresponding motional state. The quantum gate is the elementary evolution operator corresponding to the time-dependent Schrödinger equation of the simulated system. The corresponding matrix can be estimated by any numerical algorithm. The radio-frequency field which is able to drive this unitary transformation among the qubit states of the ion is obtained by multi-target optimal control theory. The ion is assumed to be cooled in the ground motional state, and the preliminary step consists in initializing the qubits with the amplitudes of the initial simulated wave packet. The time evolution of the localization probability at the grids points is then obtained by successive applications of the gate and reading out the motional state population. The gate field is always identical for a given simulated potential, only the field preparing the initial wave packet has to be optimized for different simulations. We check the stability of the simulation against decoherence due to fluctuating electric fields in the trap electrodes by applying dissipative Lindblad dynamics. © 2015 AIP Publishing LLC.
BibTeX:
@article{Santos2015,
  author = {Santos, L. and Justum, Y. and Vaeck, N. and Desouter-Lecomte, M.},
  title = {Simulation of the elementary evolution operator with the motional states of an ion in an anharmonic trap},
  journal = {Journal of Chemical Physics},
  year = {2015},
  volume = {142},
  article number = {134304},
  doi = {10.1063/1.4916355}
}
Abstract: A new approach to simulating rotational cooling using a direct simulation Monte Carlo (DSMC) method is described and applied to the rotational cooling of ammonia seeded into a helium supersonic jet. The method makes use of ab initio rotational state changing cross sections calculated as a function of collision energy. Each particle in the DSMC simulations is labelled with a vector of rotational populations that evolves with time. Transfer of energy into translation is calculated from the mean energy transfer for this population at the specified collision energy. The simulations are compared with a continuum model for the on-axis density, temperature and velocity; rotational temperature as a function of distance from the nozzle is in accord with expectations from experimental measurements. The method could be applied to other types of gas mixture dynamics under non-uniform conditions, such as buffer gas cooling of NH3 by He. © 2015 Taylor and Francis.
BibTeX:
@article{Schullian2015,
  author = {Schullian, O. and Loreau, J. and Vaeck, N. and Avoird, A.V.D. and Heazlewood, B.R. and Rennick, C.J. and Softley, T.P.},
  title = {Simulating rotationally inelastic collisions using a direct simulation Monte Carlo method},
  journal = {Molecular Physics},
  year = {2015},
  volume = {113},
  pages = {3972-3978},
  doi = {10.1080/00268976.2015.1098740}
}
BibTeX:
@article{Softley2015,
  author = {Softley, T. and Herman, M. and Vaeck, N.},
  title = {Special issue on atomic and molecular collision mechanisms},
  journal = {Molecular Physics},
  year = {2015},
  volume = {113},
  pages = {3917},
  doi = {10.1080/00268976.2015.1114702}
}
Abstract: The vertical columns of formaldehyde (HCHO) retrieved from two satellite instruments, the Global Ozone Monitoring Instrument-2 (GOME-2) on Metop-A and the Ozone Monitoring Instrument (OMI) on Aura, are used to constrain global emissions of HCHO precursors from open fires, vegetation and human activities in the year 2010. To this end, the emissions are varied and optimized using the adjoint model technique in the IMAGESv2 global CTM (chemical transport model) on a monthly basis and at the model resolution. Given the different local overpass times of GOME-2 (09:30 LT) and OMI (13:30 LT), the simulated diurnal cycle of HCHO columns is investigated and evaluated against ground-based optical measurements at seven sites in Europe, China and Africa. The modeled diurnal cycle exhibits large variability, reflecting competition between photochemistry and emission variations, with noon or early afternoon maxima at remote locations (oceans) and in regions dominated by anthropogenic emissions, late afternoon or evening maxima over fire scenes, and midday minima in isoprene-rich regions. The agreement between simulated and ground-based columns is generally better in summer (with a clear afternoon maximum at mid-latitude sites) than in winter, and the annually averaged ratio of afternoon to morning columns is slightly higher in the model (1.126) than in the ground-based measurements (1.043). The anthropogenic VOC (volatile organic compound) sources are found to be weakly constrained by the inversions on the global scale, mainly owing to their generally minor contribution to the HCHO columns, except over strongly polluted regions, like China. The OMI-based inversion yields total flux estimates over China close to the bottom-up inventory (24.6 vs. 25.5 TgVOC yrg-1 in the a priori) with, however, pronounced increases in the northeast of China and reductions in the south. Lower fluxes are estimated based on GOME-2 HCHO columns (20.6 TgVOC yrg-1), in particular over the northeast, likely reflecting mismatches between the observed and the modeled diurnal cycle in this region. The resulting biogenic and pyrogenic flux estimates from both optimizations generally show a good degree of consistency. A reduction of the global annual biogenic emissions of isoprene is derived, of 9 and 13 % according to GOME-2 and OMI, respectively, compared to the a priori estimate of 363 Tg in 2010. The reduction is largest (up to 25-40 %) in the Southeastern US, in accordance with earlier studies. The GOME-2 and OMI satellite columns suggest a global pyrogenic flux decrease by 36 and 33 %, respectively, compared to the GFEDv3 (Global Fire Emissions Database) inventory. This decrease is especially pronounced over tropical forests, such as in Amazonia, Thailand and Myanmar, and is supported by comparisons with CO observations from IASI (Infrared Atmospheric Sounding Interferometer). In contrast to these flux reductions, the emissions due to harvest waste burning are strongly enhanced over the northeastern China plain in June (by ca. 70 % in June according to OMI) as well as over Indochina in March. Sensitivity inversions showed robustness of the inferred estimates, which were found to lie within 7 % of the standard inversion results at the global scale. © Author(s) 2015.
BibTeX:
@article{Stavrakou2015,
  author = {Stavrakou, T. and Müller, J.-F. and Bauwens, M. and De Smedt, I. and Van Roozendael, M. and De Mazière, M. and Vigouroux, C. and Hendrick, F. and George, M. and Clerbaux, C. and Coheur, P.-F. and Guenther, A.},
  title = {How consistent are top-down hydrocarbon emissions based on formaldehyde observations from GOME-2 and OMI?},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {11861-11884},
  doi = {10.5194/acp-15-11861-2015}
}
Abstract: Two setups based on CW cavity ring-down spectroscopy were used at Bruxelles and Rennes to record jet-cooled water dimer absorption between 7188 and 7285, and between 7357 and 7386 cm-1. Some 19 absorption features are reported, significantly more than in the literature. Limited high-resolution information is available due to strong overlap between neighboring vibration-rotation-tunneling (VRT) structures and to spectral broadening induced by short upper state vibrational predissociation lifetimes, likely to range between 100 and 20 ps. Rotational band contours analyses are performed to assign the partly resolved VRT structures to the v1v2v3,vfvb = 000,11; 200,00; 000,20; and 101,00 zero-order vibrational states. Their wavenumbers are found to be 7192.34, 7225.86, 7240.57, and 7256.99 cm-1, respectively. Both so-called acceptor-switching tunneling components are involved in the assignments whose tentative character is discussed. © 2015 American Chemical Society.
BibTeX:
@article{Suas-David2015,
  author = {Suas-David, N. and Vanfleteren, T. and Földes, T. and Kassi, S. and Georges, R. and Herman, M.},
  title = {The Water Dimer Investigated in the 2OH Spectral Range Using Cavity Ring-Down Spectroscopy},
  journal = {Journal of Physical Chemistry A},
  year = {2015},
  volume = {119},
  pages = {10022-10034},
  doi = {10.1021/acs.jpca.5b06746}
}
Abstract: An examination is made of the way in which the kinetic energy operator for internal motion alone is commonly constructed in molecular quantum mechanics. It is shown that some care needs to be taken to specify the precise conditions under which the form of the operator so obtained is a valid form. Particular care is needed in constructing a reaction path Hamiltonian. © 2015 Taylor & Francis.
BibTeX:
@article{Sutcliffe2015,
  author = {Sutcliffe, B.T.},
  title = {The quantum form of the reaction path Hamiltonian},
  journal = {Molecular Physics},
  year = {2015},
  volume = {113},
  pages = {1600-1607},
  doi = {10.1080/00268976.2014.999839}
}
Abstract: We present a new data set of sulfur dioxide (SO2) vertical columns from observations of the Ozone Monitoring Instrument (OMI)/AURA instrument between 2004 and 2013. The retrieval algorithm used is an advanced Differential Optical Absorption Spectroscopy (DOAS) scheme combined with radiative transfer calculation. It is developed in preparation for the operational processing of SO2 data product for the upcoming TROPOspheric Monitoring Instrument/Sentinel 5 Precursor mission. We evaluate the SO2 column results with those inferred from other satellite retrievals such as Infrared Atmospheric Sounding Interferometer and OMI (Linear Fit and Principal Component Analysis algorithms). A general good agreement between the different data sets is found for both volcanic and anthropogenic SO2 emission scenarios. We show that our algorithm produces SO2 columns with low noise and is able to provide accurate estimates of SO2. This conclusion is supported by important validation results over the heavily polluted site of Xianghe (China). Nearly 4 years of OMI and ground-based multiaxis DOAS SO2 columns are compared, and an excellent match is found. We also highlight the improved performance of the algorithm in capturing weak SO2 sources by detecting shipping SO2 emissions in long-term averaged data, an unreported measurement from space. ©2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Theys2015,
  author = {Theys, N. and De Smedt, I. and Van Gent, J. and Danckaert, T. and Wang, T. and Hendrick, F. and Stavrakou, T. and Bauduin, S. and Clarisse, L. and Li, C. and Krotkov, N. and Yu, H. and Brenot, H. and Van Roozendael, M.},
  title = {Sulfur dioxide vertical column DOAS retrievals from the Ozone Monitoring Instrument: Global observations and comparison to ground-based and satellite data},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2015},
  volume = {120},
  pages = {2470-2491},
  doi = {10.1002/2014JD022657}
}
Abstract: Differential cross sections (DCSs) are reported for rotationally inelastic scattering of ND3 with H2, measured using a crossed molecular beam apparatus with velocity map imaging (VMI). ND3 molecules were quantum-state selected in the ground electronic and vibrational levels and, optionally, in the j±k = 14- rotation-inversion level prior to collisions. Inelastic scattering of state-selected ND3 with H2 was measured at the mean collision energy of 580 cm-1 by resonance-enhanced multiphoton ionisation spectroscopy and VMI of ND3 in selected single final j'±k' levels. Comparison of experimental DCSs with close-coupling quantum-mechanical scattering calculations serves as a test of a recently reported ab initio potential energy surface. Calculated integral cross sections reveal the propensities for scattering into various final j'±k' levels of ND3 and differences between scattering by ortho and para H2. Integral and differential cross sections are also computed at a mean collision energy of 430 cm-1 and compared to our recent results for inelastic scattering of state-selected ND3 with He. © 2015 Taylor and Francis.
BibTeX:
@article{Tkac2015,
  author = {Tkáč, O. and Saha, A.K. and Loreau, J. and Ma, Q. and Dagdigian, P.J. and Parker, D.H. and Van Der Avoird, A. and Orr-Ewing, A.J.},
  title = {Rotationally inelastic scattering of ND 3 with H 2 as a probe of the intermolecular potential energy surface},
  journal = {Molecular Physics},
  year = {2015},
  volume = {113},
  pages = {3925-3933},
  doi = {10.1080/00268976.2015.1059958}
}
Abstract: Rotationally inelastic scattering of ND3 with Ar is studied at mean collision energies of 410 and 310 cm-1. In the experimental component of the study, ND3 molecules are prepared by supersonic expansion and subsequent hexapole state selection in the ground electronic and vibrational levels and in the jk±= 11- rotational level. A beam of state-selected ND3 molecules is crossed with a beam of Ar, and scattered ND3 molecules are detected in single final j′k′± quantum states using resonance enhanced multiphoton ionization spectroscopy. State-to-state differential cross sections for rotational-level changing collisions are obtained by velocity map imaging. The experimental measurements are compared with close-coupling quantum-mechanical scattering calculations performed using an ab initio potential energy surface. The computed DCSs agree well with the experimental measurements, confirming the high quality of the potential energy surface. The angular distributions are dominated by forward scattering for all measured final rotational and vibrational inversion symmetry states. This outcome is in contrast to our recent results for inelastic scattering of ND3 with He, where we observed significant amount of sideways and backward scattering for some final rotational levels of ND3. The differences between He and Ar collision partners are explained by differences in the potential energy surfaces that govern the scattering dynamics. © 2014 American Chemical Society.
BibTeX:
@article{Tkac2015a,
  author = {Tkáč, O. and Saha, A.K. and Loreau, J. and Parker, D.H. and Van Der Avoird, A. and Orr-Ewing, A.J.},
  title = {Rotationally Inelastic Scattering of Quantum-State-Selected ND3 with Ar},
  journal = {Journal of Physical Chemistry A},
  year = {2015},
  volume = {119},
  pages = {5979-5987},
  doi = {10.1021/jp5115042}
}
Abstract: By analyzing measured infrared absorption of pure CH4 gas under both "free" (large sample cell) and "confined" (inside the pores of a silica xerogel sample) conditions we give a demonstration that molecule-molecule and molecule-surface collisions lead to very different propensity rules for rotational-state changes. Whereas the efficiency of collisions to change the rotational state (observed through the broadening of the absorption lines) decreases with increasing rotational quantum number J for CH4-CH4 interactions, CH4-surface collisions lead to J-independent linewidths. In the former case, some (weak) collisions are inefficient whereas, in the latter case, a single collision is sufficient to remove the molecule from its initial rotational level. Furthermore, although some gas-phase collisions leave J unchanged and only modify the angular momentum orientation and/or symmetry of the level (as observed through the spectral effects of line mixing), this is not the case for the molecule-surface collisions since they always change J (in the studied J=0-14 range). © 2015 American Physical Society.
BibTeX:
@article{Tran2015,
  author = {Tran, H. and Vander Auwera, J. and Landsheere, X. and Ngo, N.H. and Pangui, E. and Morales, S.B. and El Hamzaoui, H. and Capoen, B. and Bouazaoui, M. and Boulet, C. and Hartmann, J.-M.},
  title = {Infrared light on molecule-molecule and molecule-surface collisions},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2015},
  volume = {92},
  article number = {012707},
  doi = {10.1103/PhysRevA.92.012707}
}
Abstract: This study aims to investigate some characteristics of the moist processes of the Madden-Julian oscillation (MJO), by making use of joint HDO (or δD) and H2O vapor measurements. The MJO is the main intraseasonal mode of the tropical climate but is hard to properly simulate in global atmospheric models. The joint use of δD-H2O diagnostics yields additional information compared to sole humidity measurements. We use midtropospheric Infrared Atmospheric Sounding Interferometer (IASI) satellite δD and H2O measurements to determine the mean MJO humidity and δD evolution. Moreover, by making use of high temporal resolution data, we determine the variability in this evolution during about eight MJO events from 2010 to 2012 (including those monitored during the DYNAMO (the Dynamics of the MJO), CINDY (Cooperative Indian Ocean Experiment in Y2011) campaign). These data have a higher spatiotemporal coverage than previous δD measurements, enabling the sampling of individual MJO events. IASI measurements over the Indian Ocean confirm earlier findings that the moistening before the precipitation peak of an MJO event is due to water vapor slightly enriched in HDO. There is then a HDO depletion around the precipitation peak that also corresponds to the moister environment. Most interevent variability determined in the current study occurs 5 to 10 days after the MJO event. In 75% of the events, humidity decreases while the atmosphere remains depleted. In a quarter of the events, humidity increases simultaneously with an increase in δD. After this, the advection of relatively dry and enriched air brings back the state to the mean. Over the maritime continent, δD-H2O cycles are more variable on time scales shorter than the MJO and the interevent variability is larger than over the Indian Ocean. The sequence of moistening and drying processes as revealed by the q-δD cycles can be used as a benchmark to evaluate the representation of moist processes in models. This is done here by comparing observations to simulations of the isotope enabled LMDZ (Laboratoire de Météorologie Dynamique Zoom) global climate model nudged with reanalysis wind fields. These simulations also give information to investigate possible physical origins of the observed q-δD cycles. © 2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Tuinenburg2015,
  author = {Tuinenburg, O.A. and Risi, C. and Lacour, J.L. and Schneider, M. and Wiegele, A. and Worden, J. and Kurita, N. and Duvel, J.P. and Deutscher, N. and Bony, S. and Coheur, P.F. and Clerbaux, C.},
  title = {Moist processes during MJO events as diagnosed from water isotopic measurements from the IASI satellite},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2015},
  volume = {120},
  pages = {10619-10636},
  doi = {10.1002/2015JD023461}
}
Abstract: Limited availability of ammonia (NH3) observations is currently a barrier for effective monitoring of the nitrogen cycle. It prevents a full understanding of the atmospheric processes in which this trace gas is involved and therefore impedes determining its related budgets. Since the end of 2007, the Infrared Atmospheric Sounding Interferometer (IASI) satellite has been observing NH3 from space at a high spatio-temporal resolution. This valuable data set, already used by models, still needs validation. We present here a first attempt to validate IASI-NH3 measurements using existing independent ground-based and airborne data sets. The yearly distributions reveal similar patterns between ground-based and space-borne observations and highlight the scarcity of local NH3 measurements as well as their spatial heterogeneity and lack of representativity. By comparison with monthly resolved data sets in Europe, China and Africa, we show that IASI-NH3 observations are in fair agreement, but they are characterized by a smaller variation in concentrations. The use of hourly and airborne data sets to compare with IASI individual observations allows investigations of the impact of averaging as well as the representativity of independent observations for the satellite footprint. The importance of considering the latter and the added value of densely located airborne measurements at various altitudes to validate IASI-NH3 columns are discussed. Perspectives and guidelines for future validation work on NH3 satellite observations are presented. © Author(s) 2015.
BibTeX:
@article{VanDamme2015,
  author = {Van Damme, M. and Clarisse, L. and Dammers, E. and Liu, X. and Nowak, J.B. and Clerbaux, C. and Flechard, C.R. and Galy-Lacaux, C. and Xu, W. and Neuman, J.A. and Tang, Y.S. and Sutton, M.A. and Erisman, J.W. and Coheur, P.F.},
  title = {Towards validation of ammonia (NH3) measurements from the IASI satellite},
  journal = {Atmospheric Measurement Techniques},
  year = {2015},
  volume = {8},
  pages = {1575-1591},
  doi = {10.5194/amt-8-1575-2015}
}
Abstract: We exploit 6 years of measurements from the Infrared Atmospheric Sounding Interferometer (IASI)/MetOp-A instrument to identify seasonal patterns and interannual variability of atmospheric NH3. This is achieved by analyzing the time evolution of the monthly mean NH3 columns in 12 subcontinental areas around the world, simultaneously considering measurements from IASI morning and evening overpasses. For most regions, IASI has a sufficient sensitivity throughout the years to capture the seasonal patterns of NH3 columns, and we show that each region is characterized by a well-marked and distinctive cycle, with maxima mainly related to underlying emission processes. The largest column abundances and seasonal amplitudes throughout the years are found in southwestern Asia, with maxima twice as large as what is observed in southeastern China. The relation between emission sources and retrieved NH3 columns is emphasized at a smaller regional scale by inferring a climatology of the month of maximum columns. Key Points Six years of NH3 morning and evening IASI measurements are analyzed Seasonal cycles of atmospheric NH3 are characterized for subcontinental areas Source processes are attributed from a climatology of the month of NH3 maximum © 2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{VanDamme2015a,
  author = {Van Damme, M. and Erisman, J.W. and Clarisse, L. and Dammers, E. and Whitburn, S. and Clerbaux, C. and Dolman, A.J. and Coheur, P.-F.},
  title = {Worldwide spatiotemporal atmospheric ammonia (NH3) columns variability revealed by satellite},
  journal = {Geophysical Research Letters},
  year = {2015},
  volume = {42},
  pages = {8660-8668},
  doi = {10.1002/2015GL065496}
}
Abstract: Two major droughts in the past decade had large impacts on carbon exchange in the Amazon. Recent analysis of vertical profile measurements of atmospheric CO2 and CO by Gatti et al. (2014) suggests that the 2010 drought turned the normally close-to-neutral annual Amazon carbon balance into a substantial source of nearly 0.5 PgC/yr, revealing a strong drought response. In this study, we revisit this hypothesis and interpret not only the same CO2/CO vertical profile measurements but also additional constraints on carbon exchange such as satellite observations of CO, burned area, and fire hot spots. The results from our CarbonTracker South America data assimilation system suggest that carbon uptake by vegetation was indeed reduced in 2010 but that the magnitude of the decrease strongly depends on the estimated 2010 and 2011 biomass burning emissions. We have used fire products based on burned area (Global Fire Emissions Database version 4), satellite-observed CO columns (Infrared Atmospheric Sounding Interferometer), fire radiative power (Global Fire Assimilation System version 1), and fire hot spots (Fire Inventory from NCAR version 1), and found an increase in biomass burning emissions in 2010 compared to 2011 of 0.16 to 0.24 PgC/yr. We derived a decrease of biospheric uptake ranging from 0.08 to 0.26 PgC/yr, with the range determined from a set of alternative inversions using different biomass burning estimates. Our numerical analysis of the 2010 Amazon drought results in a total reduction of carbon uptake of 0.24 to 0.50 PgC/yr and turns the balance from carbon sink to source. Our findings support the suggestion that the hydrological cycle will be an important driver of future changes in Amazonian carbon exchange. Key Points Amazon carbon budget estimated by CarbonTracker South America Biospheric uptake decreases by 0.08-0.26 PgC/yr in response to 2010 drought Amazon biomass burning emissions more than doubled during 2010 drought ©2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{VanDerLaan-Luijkx2015,
  author = {Van Der Laan-Luijkx, I.T. and Van Der Velde, I.R. and Krol, M.C. and Gatti, L.V. and Domingues, L.G. and Correia, C.S.C. and Miller, J.B. and Gloor, M. and Van Leeuwen, T.T. and Kaiser, J.W. and Wiedinmyer, C. and Basu, S. and Clerbaux, C. and Peters, W.},
  title = {Response of the Amazon carbon balance to the 2010 drought derived with CarbonTracker South America},
  journal = {Global Biogeochemical Cycles},
  year = {2015},
  volume = {29},
  pages = {1092-1108},
  doi = {10.1002/2014GB005082}
}
Abstract: The NOMAD spectrometer suite on the ExoMars Trace Gas Orbiter will map the composition and distribution of Mars’atmospheric trace species in unprecedented detail, fulfilling many of the scientific objectives of the joint ESA-Roscosmos ExoMars Trace Gas Orbiter mission. The instrument is a combination of three channels, covering a spectral range from the UV to the IR, and can perform solar occultation, nadir and limb observations. In this paper, we present the science objectives of the instrument and how these objectives have influenced the design of the channels. We also discuss the expected performance of the instrument in terms of coverage and detection sensitivity. © 2015 Elsevier Ltd. All rights reserved.
BibTeX:
@article{Vandaele2015,
  author = {Vandaele, A.C. and Neefs, E. and Drummond, R. and Thomas, I.R. and Daerden, F. and Lopez-Moreno, J.-J. and Rodriguez, J. and Patel, M.R. and Bellucci, G. and Allen, M. and Altieri, F. and Bolsée, D. and Clancy, T. and Delanoye, S. and Depiesse, C. and Cloutis, E. and Fedorova, A. and Formisano, V. and Funke, B. and Fussen, D. and Geminale, A. and Gérard, J.-C. and Giuranna, M. and Ignatiev, N. and Kaminski, J. and Karatekin, O. and Lefèvre, F. and López-Puertas, M. and López-Valverde, M. and Mahieux, A. and McConnell, J. and Mumma, M. and Neary, L. and Renotte, E. and Ristic, B. and Robert, S. and Smith, M. and Trokhimovsky, S. and Vanderauwera, J. and Villanueva, G. and Whiteway, J. and Wilquet, V. and Wolff, M. and Vandaele, A.C. and Lopez Moreno, J.J. and Bellucci, G. and Patel, M. and Allen, M. and Altieri, F. and Aoki, S. and Bolsée, D. and Clancy, T. and Cloutis, E. and Daerden, F. and Depiesse, C. and Fedorova, A. and Formisano, V. and Funke, B. and Fussen, D. and Garcia-Comas, M. and Geminale, A. and Gérard, J.-C. and Gillotay, D. and Giuranna, M. and Gonzalez-Galindo, F. and Ignatiev, N. and Kaminski, J. and Karatekin, O. and Kasabe, Y. and Lefèvre, F. and Lewis, S. and López-Puertas, M. and López-Valverde, M. and Mahieux, A. and Mason, J. and Mumma, M. and Neary, L. and Neefs, E. and Renotte, E. and Robert, S. and Sindoni, G. and Smith, M. and Thomas, I.R. and Trokhimovsky, S. and Vander Auwera, J. and Villanueva, G. and Whiteway, J. and Willame, Y. and Wilquet, V. and Wolff, M. and Alonso-Rodrigo, G. and Aparicio Del Moral, B. and Barzin, P. and Ben Moussa, A. and Berkenbosch, S. and Biondi, D. and Bonnewijn, S. and Candini, G.P. and Clairquin, R. and Cubas, J. and Delanoye, S. and Giordanengo, B. and Gissot, S. and Gomez, A. and Zafra, J.-J. and Leese, M. and Maes, J. and Mazy, E. and Mazzoli, A. and Meseguer, J. and Morales, R. and Orban, A. and Pastor-Morales, M.D.C. and Perez-Grande, I. and Ristic, B. and Rodriguez-Gomez, J. and Saggin, B. and Samain, V. and Sanz Andres, A. and Sanz, R. and Simar, J.-F. and Thibert, T.},
  title = {Science objectives and performances of NOMAD, a spectrometer suite for the ExoMars TGO mission},
  journal = {Planetary and Space Science},
  year = {2015},
  volume = {119},
  pages = {233-249},
  doi = {10.1016/j.pss.2015.10.003}
}
Abstract: The NOMAD instrument has been designed to best fulfil the science objectives of the ExoMars Trace Gas Orbiter mission that will be launched in 2016. The instrument is a combination of three channels that cover the UV, visible and IR spectral ranges and can perform solar occultation, nadir and limb observations. In this series of two papers, we present the optical models representing the three channels of the instrument and use them to determine signal to noise levels for different observation modes and Martian conditions. In this first part, we focus on the UVIS channel, which will sound the Martian atmosphere using nadir and solar occultation viewing modes, covering the 200-650nm spectral range. High SNR levels (>1000) can easily be reached for wavelengths higher than 300nm both in solar occultation and nadir modes when considering binning. Below 300nm SNR are lower primarily because of the lower signal and the impact of atmospheric absorption. © 2015 Optical Society of America.
BibTeX:
@article{Vandaele2015a,
  author = {Vandaele, A.C. and Willame, Y. and Depiesse, C. and Thomas, I.R. and Robert, S. and Bolsée, D. and Patel, M.R. and Mason, J.P. and Leese, M. and Lesschaeve, S. and Antoine, P. and Daerden, F. and Delanoye, S. and Drummond, R. and Neefs, E. and Ristic, B. and Lopez-Moreno, J.-J. and Bellucci, G. and Allen, M. and Altieri, F. and Aoki, S. and Clancy, T. and Cloutis, E. and Fedorova, A. and Formisano, V. and Funke, B. and Fussen, D. and Garcia-Comas, M. and Geminale, A. and Gérard, J.-C. and Gillotay, D. and Giuranna, M. and Gonzalez-Galindo, F. and Ignatiev, N. and Kaminski, J. and Karatekin, O. and Kasaba, Y. and Lefèvre, F. and Lewis, S. and López-Puertas, M. and López-Valverde, M. and Mahieux, A. and Mumma, M. and Neary, L. and Novak, R. and Renotte, E. and Sindoni, G. and Smith, M. and Trokhimovskiy, A. and Vander Auwera, J. and Villanueva, G. and Viscardy, S. and Whiteway, J. and Wilquet, V. and Wolff, M. and Alonso-Rodrigo, G. and Aparicio Del Moral, B. and Barzin, P. and BenMoussa, A. and Berkenbosch, S. and Biondi, D. and Bonnewijn, S. and Candini, G. and Clairquin, R. and Cubas, J. and Giordanengo, B. and Gissot, S. and Gomez, A. and Zafra, J.-J. and Maes, J. and Mazy, E. and Mazzoli, A. and Meseguer, J. and Morales, R. and Orban, A. and Pastor-Morales, M. and Perez-Grande, I. and Rodriguez-Gomez, J. and Saggin, B. and Samain, V. and Sanz Andres, A. and Sanz, R. and Simar, J.-F. and Thibert, T.},
  title = {Optical and radiometric models of the NOMAD instrument Part I: The UVIS channel},
  journal = {Optics Express},
  year = {2015},
  volume = {23},
  pages = {30028-30042},
  doi = {10.1364/OE.23.030028}
}
Abstract: We have used continuous-wave cavity ring-down spectroscopy to record a band with origin close to 7273.5 cm-1 in a Kr supersonic expansion seeded with H2O. It is assigned to ν1 + ν3 ← GS, Π(101) ← Σ(000) in KrH2O. Several lines of the four most abundant Kr isotopic forms are resolved. The rotational structure (Trot = 18 K) is analyzed and the lines fitted (σ < 0.0004 cm-1) together with literature microwave data. The mean upper state predissociation lifetime is estimated to 4 ns. © 2014 Elsevier B.V. All rights reserved.
BibTeX:
@article{Vanfleteren2015a,
  author = {Vanfleteren and Földes, T. and Vander Auwera, J. and Herman, M.},
  title = {Analysis of a remarkable perpendicular band in KrH2O with origin close to the ν1 + ν3 R(0) line in H2O},
  journal = {Chemical Physics Letters},
  year = {2015},
  volume = {618},
  pages = {119-122},
  doi = {10.1016/j.cplett.2014.11.010}
}
Abstract: We have used continuous-wave cavity ring-down spectroscopy to record a band with origin close to 7275.1 cm-1 in an Ar supersonic expansion seeded with H2O. It is assigned to ν1 + ν3 ← GS, Π(101) ← Σ(000) in Ar-H2O. The rotational structure (Trot = 12 K) is analyzed and the lines fitted (σ = 0.0008 cm-1) together with literature microwave data. The fit includes strongly perturbed Q lines, from interaction with a Π state with origin determined to be close to 7274.5 cm-1. The mean upper state predissociation lifetime is determined to be 3 ns for all reported e and f upper levels. © 2015 Elsevier B.V. All rights reserved.
BibTeX:
@article{Vanfleteren2015b,
  author = {Vanfleteren, T. and Földes, T. and Herman, M.},
  title = {Analysis of a perpendicular band in Ar-H2O with origin close to the ν1 + ν3, R(0) line in H2O},
  journal = {Chemical Physics Letters},
  year = {2015},
  volume = {627},
  pages = {36-38},
  doi = {10.1016/j.cplett.2015.03.032}
}
Abstract: We report on the observation of the Π (11; 2NH) ← Σ (00; ground state) band in 15NH3-Ar, with origin at 6615.943 cm-1, using jet-cooled cw-cavity ring-down spectroscopy. The rotational temperature is estimated to be 7 K. Nineteen rotational lines were assigned. Perturbations were evidenced from anomalous line positions and line widths, but not unraveled. Upper state rotational constants were obtained from the analysis of the nine unperturbed R/P lines. The e-symmetry upper state predissociation lifetimes appear to decrease with J′, from about 1.2 ns to 250 ps from J′ = 1 to 9. © 2015 Elsevier Inc. All rights reserved.
BibTeX:
@article{Vanfleteren2015,
  author = {Vanfleteren, T. and Földes, T. and Herman, M. and Di Lonardo, G. and Fusina, L.},
  title = {Overtone, 2NH (ν1 + ν3) spectroscopy of 15NH3-Ar},
  journal = {Journal of Molecular Spectroscopy},
  year = {2015},
  volume = {318},
  pages = {107-109},
  doi = {10.1016/j.jms.2015.10.011}
}
Abstract: We have recorded between 6561 and 6671 cm-1 the spectrum of jet-cooled ammonia seeded in Ne, Ar and Kr, using continuous wave cavity ring-down spectroscopy (CW-CRDS). The equivalent absorption pathlength was around 750 m. Three bands are assigned to Π(11)←Σ(00), Π(11)←Π(10) and Δ(?)←Π(10) in the 2NH, 1+3←GS transition of the ortho NH3-Ar dimer. They are rotationally analysed and a simultaneous fitting procedure, together with one far-infrared ground state band from the literature is successfully achieved. A possible Mj-dependent cooling process is reported. Only the first of these bands is observed in the ortho NH3-Kr dimer, and rotationally analysed. Individual line perturbations and anomalous line broadening effects are reported. A J-dependent vibrational predissociation lifetime with a mean value around 0.6 ns is obtained for the Π(11) sub-state in NH3-Ar and NH3-Kr. Two additional bands are assigned to NH3-Ar involving close Π upper sub-states. A group of close bands from the para dimer is identified in NH3-Ar. The energy of all observed ortho and para sub-states is extracted from the analysis. Finally, more bands are reported but their carriers could not be identified. © 2015 Taylor and Francis.
BibTeX:
@article{Vanfleteren2015c,
  author = {Vanfleteren, T. and Földes, T. and Liévin, J. and Herman, M.},
  title = {Overtone, 2NH ( 1+ 3) spectroscopy of NH 3-Ar and NH 3-Kr},
  journal = {Molecular Physics},
  year = {2015},
  volume = {113},
  pages = {3934-3945},
  doi = {10.1080/00268976.2015.1072252}
}
Abstract: The photodissociation and laser assisted dissociation of the carbon monoxide dication X3Π CO2+ into the 3Σ- states are investigated. Ab initio electronic structure calculations of the adiabatic potential energy curves, radial nonadiabatic couplings, and dipole moments for the X 3Π state are performed for 13 excited 3Σ- states of CO2+. The photodissociation cross section, calculated by time-dependent methods, shows that the C+ + O+ channels dominate the process in the studied energy range. The carbon monoxide dication CO2+ is an interesting candidate for control because it can be produced in a single, long lived, v = 0 vibrational state due to the instability of all the other excited vibrational states of the ground 3Π electronic state. In a spectral range of about 25 eV, perpendicular transition dipoles couple this 3Π state to a manifold of 3Σ- excited states leading to numerous C+ + O+ channels and a single C2+ + O channel. This unique channel is used as target for control calculations using local control theory. We illustrate the efficiency of this method in order to find a tailored electric field driving the photodissociation in a manifold of strongly interacting electronic states. The selected local pulses are then concatenated in a sequence inspired by the "laser distillation" strategy. Finally, the local pulse is compared with optimal control theory. © 2015 AIP Publishing LLC.
BibTeX:
@article{Vranckx2015,
  author = {Vranckx, S. and Loreau, J. and Vaeck, N. and Meier, C. and Desouter-Lecomte, M.},
  title = {Photodissociation of the carbon monoxide dication in the 3Σ- manifold: Quantum control simulation towards the C2+ + O channel},
  journal = {Journal of Chemical Physics},
  year = {2015},
  volume = {143},
  article number = {164309},
  doi = {10.1063/1.4934233}
}
Abstract: The Monitoring Atmospheric Composition and Climate (MACC) project represents the European Union's Copernicus Atmosphere Monitoring Service (CAMS) (http://www.copernicus.eu/), which became fully operational during 2015. The global near-real-time MACC model production run for aerosol and reactive gases provides daily analyses and 5-day forecasts of atmospheric composition fields. It is the only assimilation system worldwide that is operational to produce global analyses and forecasts of reactive gases and aerosol fields. We have investigated the ability of the MACC analysis system to simulate tropospheric concentrations of reactive gases covering the period between 2009 and 2012. A validation was performed based on carbon monoxide (CO), nitrogen dioxide (NO2) and ozone (O3) surface observations from the Global Atmosphere Watch (GAW) network, the O3 surface observations from the European Monitoring and Evaluation Programme (EMEP) and, furthermore, NO2 tropospheric columns, as well as CO total columns, derived from satellite sensors. The MACC system proved capable of reproducing reactive gas concentrations with consistent quality; however, with a seasonally dependent bias compared to surface and satellite observations - for northern hemispheric surface O3 mixing ratios, positive biases appear during the warm seasons and negative biases during the cold parts of the year, with monthly modified normalised mean biases (MNMBs) ranging between -30 and 30 % at the surface. Model biases are likely to result from difficulties in the simulation of vertical mixing at night and deficiencies in the model's dry deposition parameterisation. Observed tropospheric columns of NO2 and CO could be reproduced correctly during the warm seasons, but are mostly underestimated by the model during the cold seasons, when anthropogenic emissions are at their highest level, especially over the US, Europe and Asia. Monthly MNMBs of the satellite data evaluation range from values between -110 and 40 % for NO2 and at most -20 % for CO, over the investigated regions. The underestimation is likely to result from a combination of errors concerning the dry deposition parameterisation and certain limitations in the current emission inventories, together with an insufficiently established seasonality in the emissions. © Author(s) 2015.
BibTeX:
@article{Wagner2015,
  author = {Wagner, A. and Blechschmidt, A.-M. and Bouarar, I. and Brunke, E.-G. and Clerbaux, C. and Cupeiro, M. and Cristofanelli, P. and Eskes, H. and Flemming, J. and Flentje, H. and George, M. and Gilge, S. and Hilboll, A. and Inness, A. and Kapsomenakis, J. and Richter, A. and Ries, L. and Spangl, W. and Stein, O. and Weller, R. and Zerefos, C.},
  title = {Evaluation of the MACC operational forecast system - Potential and challenges of global near-real-time modelling with respect to reactive gases in the troposphere},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {14005-14030},
  doi = {10.5194/acp-15-14005-2015}
}
Abstract: Vegetation fires emit large amounts of nitrogen compounds in the atmosphere, including ammonia (NH3). These emissions are still subject to large uncertainties. In this study, we analyze time series of monthly NH3 total columns (molec cm-2) from the IASI sounder on board MetOp-A satellite and their relation with MODIS fire radiative power (MW) measurements. We derive monthly NH3 emissions estimates for four regions accounting for a major part of the total area affected by fires (two in Africa, one in central South America and one in Southeast Asia), using a simplified box model, and we compare them to the emissions from both the GFEDv3.1 and GFASv1.0 biomass burning emission inventories. In order to strengthen the analysis, we perform a similar comparison for carbon monoxide (CO), also measured by IASI and for which the emission factors used in the inventories to convert biomass burned to trace gas emissions are thought to be more reliable. In general, a good correspondence between NH3 and CO columns and the FRP is found, especially for regions in central South America with correlation coefficients of 0.82 and 0.66, respectively. The comparison with the two biomass burning emission inventories GFASv1.0 and GFEDv3.1 shows good agreements, particularly in the time of the maximum of emissions for the central South America region and in the magnitude for the region of Africa south of the equator. We find evidence of significant non-pyrogenic emissions for the regions of Africa north of the equator (for NH3) and Southeast Asia (for NH3 and CO). On a yearly basis, total emissions calculated from IASI measurements for the four regions reproduce fairly well the interannual variability from the GFEDv3.1 and GFASv1.0 emissions inventories for NH3 but show values about 1.5-2 times higher than emissions given by the two biomass burning emission inventories, even when assuming a fairly long lifetime of 36 h for that species. © 2015 Elsevier Ltd.
BibTeX:
@article{Whitburn2015,
  author = {Whitburn, S. and Van Damme, M. and Kaiser, J.W. and Van Der Werf, G.R. and Turquety, S. and Hurtmans, D. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F.},
  title = {Ammonia emissions in tropical biomass burning regions: Comparison between satellite-derived emissions and bottom-up fire inventories},
  journal = {Atmospheric Environment},
  year = {2015},
  volume = {121},
  pages = {42-54},
  doi = {10.1016/j.atmosenv.2015.03.015}
}
Abstract: Most satellite models of production have been designed and calibrated for use in the open ocean. Coastal waters are optically more complex, and the use of chlorophyll a (chl a) as a first-order predictor of primary production may lead to substantial errors due to significant quantities of coloured dissolved organic matter (CDOM) and total suspended material (TSM) within the first optical depth. We demonstrate the use of phytoplankton absorption as a proxy to estimate primary production in the coastal waters of the North Sea and Western English Channel for both total, micro- and nano+pico-phytoplankton production. The method is implemented to extrapolate the absorption coefficient of phytoplankton and production at the sea surface to depth to give integrated fields of total and micro- and nano+pico-phytoplankton primary production using the peak in absorption coefficient at red wavelengths. The model is accurate to 8% in the Western English Channel and 22% in this region and the North Sea. By comparison, the accuracy of similar chl a based production models was >250%. The applicability of the method to autonomous optical sensors and remotely sensed aircraft data in both coastal and estuarine environments is discussed. © Inter-Research 2014.
BibTeX:
@article{Barnes2014,
  author = {Barnes, M.K. and Tilstone, G.H. and Smyth, T.J. and Suggett, D.J. and Astoreca, R. and Lancelot, C. and Kromkamp, J.C.},
  title = {Absorption-based algorithm of primary production for total and size-fractionated phytoplankton in coastal waters},
  journal = {Marine Ecology Progress Series},
  year = {2014},
  volume = {504},
  pages = {73-89},
  doi = {10.3354/meps10751}
}
Abstract: We estimate the CO2 flux over Tropical Asia in 2009, 2010, and 2011 using Greenhouse Gases Observing Satellite (GOSAT) total column CO 2(XCO2) and in situ measurements of CO2. Compared to flux estimates from assimilating surface measurements of CO 2, GOSAT XCO2 estimates a more dynamic seasonal cycle and a large source in March-May 2010. The more dynamic seasonal cycle is consistent with earlier work by Patra et al. (2011), and the enhanced 2010 source is supported by independent upper air CO2 measurements from the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project. Using Infrared Atmospheric Sounding Interferometer (IASI) measurements of total column CO (XCO), we show that biomass burning CO2 can explain neither the dynamic seasonal cycle nor the 2010 source. We conclude that both features must come from the terrestrial biosphere. In particular, the 2010 source points to biosphere response to above-average temperatures that year. Key Points GOSAT estimates a dynamic seasonal cycle over Tropical Asia The GOSAT-estimated seasonal cycle is confirmed by CONTRAIL data IASI CO shows that the dynamism is not caused by biomass burning ©2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Basu2014,
  author = {Basu, S. and Krol, M. and Butz, A. and Clerbaux, C. and Sawa, Y. and Machida, T. and Matsueda, H. and Frankenberg, C. and Hasekamp, O.P. and Aben, I.},
  title = {The seasonal variation of the CO2 flux over Tropical Asia estimated from GOSAT, CONTRAIL, and IASI},
  journal = {Geophysical Research Letters},
  year = {2014},
  volume = {41},
  pages = {1809-1815},
  doi = {10.1002/2013GL059105}
}
Abstract: Norilsk is one of the most polluted cities in the world, largely because of intense mining of heavy metals. Here we present satellite observations of SO2 in a large area surrounding the city, derived from 4 years of measurements from the Infrared Atmospheric Sounding Interferometer (IASI), the nadir thermal infrared (TIR) sounder onboard the MetOp platforms. TIR instruments are conventionally considered to be inadequate for monitoring near-surface composition, because their sensitivity to the lowest part of the atmosphere is limited by the thermal contrast between the ground and the air above it. We demonstrate that IASI is capable of measuring SO2 (here as a partial column from 0 to 2 km) in Norilsk, thanks to the large temperature inversions and the low humidity in wintertime. We discuss the influence of thermal contrast and of surface humidity on the SO2 retrieved columns and estimate the retrieval errors. Using a simple box model, we derive the yearly total emissions of SO2 from Norilsk and compare them to previously reported values. More generally, we present in this work the first large-scale demonstration of the capability of space-based TIR sounders to measure near-surface SO2 anthropogenic pollution. © 2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Bauduin2014,
  author = {Bauduin, S. and Clarisse, L. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F.},
  title = {IASI observations of sulfur dioxide (SO2) in the boundary layer of Norilsk},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2014},
  volume = {119},
  article number = {A1},
  doi = {10.1002/2013JD021405}
}
Abstract: The Lagrange-mesh method is an approximate variational method taking the form of equations on a grid because of the use of a Gauss quadrature approximation. With a basis of Lagrange functions involving associated Laguerre polynomials related to the Gauss quadrature, the method is applied to the Dirac equation. The potential may possess a 1/r singularity. For hydrogenic atoms, numerically exact energies and wave functions are obtained with small numbers n+1 of mesh points, where n is the principal quantum number. Numerically exact mean values of powers -2 to 3 of the radial coordinate r can also be obtained with n+2 mesh points. For the Yukawa potential, a 15-digit agreement with benchmark energies of the literature is obtained with 50 or fewer mesh points. © 2014 American Physical Society.
BibTeX:
@article{Baye2014,
  author = {Baye, D. and Filippin, L. and Godefroid, M.},
  title = {Accurate solution of the Dirac equation on Lagrange meshes},
  journal = {Physical Review E - Statistical, Nonlinear, and Soft Matter Physics},
  year = {2014},
  volume = {89},
  article number = {043305},
  doi = {10.1103/PhysRevE.89.043305}
}
Abstract: We present the results of a theoretical investigation focusing on the solvent structure surrounding the -1, 0 and +1 charged species of F, Cl, Br and I halogen atoms and F2, Cl2, Br2 and I 2 di-halogen molecules in a methanol solvent and its influence on the electronic structure of the solute molecules. Our results show a large stabilizing effect arising from the solute-solvent interactions. Well-formed first solvation shells are observed for all species, the structure of which is strongly influenced by the charge of the solute species. Detailed analysis reveals that coordination number, CN, solvent orientation, and solute-solvent distance, d, are important structural characteristics which are coupled to changes in the electronic structure of the solute. We propose that the fundamental chemistry of any solute species is generally regulated by these solvent degrees of freedom. © 2014 the Owner Societies.
BibTeX:
@article{Bogatko2014,
  author = {Bogatko, S. and Cauët, E. and Geerlings, P. and De Proft, F.},
  title = {On the coupling of solvent characteristics to the electronic structure of solute molecules},
  journal = {Physical Chemistry Chemical Physics},
  year = {2014},
  volume = {16},
  pages = {3807-3814},
  doi = {10.1039/c3cp54944e}
}
Abstract: Forecasting the dispersal of volcanic clouds during an eruption is of primary importance, especially for ensuring aviation safety. As volcanic emissions are characterized by rapid variations of emission rate and height, the (generally) high level of uncertainty in the emission parameters represents a critical issue that limits the robustness of volcanic cloud dispersal forecasts. An inverse modeling scheme, combining satellite observations of the volcanic cloud with a regional chemistry-transport model, allows reconstructing this source term at high temporal resolution. We demonstrate here how a progressive assimilation of freshly acquired satellite observations, via such an inverse modeling procedure, allows for delivering robust sulfur dioxide (SO2) cloud dispersal forecasts during the eruption. This approach provides a computationally cheap estimate of the expected location and mass loading of volcanic clouds, including the identification of SO2-rich parts. Key Points Refined SO2 cloud dispersal forecasts by assimilation of satellite observations Refined estimation of source emissions using an inverse modeling approach Compared to standard methods, cloud SO2-rich parts are robustly forecasted © 2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Boichu2014,
  author = {Boichu, M. and Clarisse, L. and Khvorostyanov, D. and Clerbaux, C.},
  title = {Improving volcanic sulfur dioxide cloud dispersal forecasts by progressive assimilation of satellite observations},
  journal = {Geophysical Research Letters},
  year = {2014},
  volume = {41},
  pages = {2637-2643},
  doi = {10.1002/2014GL059496}
}
Abstract: The first quantitative description of the Rydberg and valence singlet electronic states of vinylidene lying in the 0-10 eV region is performed by using large scale ab initio calculations. A deep analysis of Rydberg-valence interactions has been achieved thanks to the comprehensive information contained in the accurate Multi-Reference Configuration Interaction wavefunctions and an original population analysis highlighting the respective role played by orbital and state mixing in such interactions. The present theoretical approach is thus adequate for dealing with larger than diatomic Rydberg systems. The nine lowest singlet valence states have been optimized. Among them, some are involved in strong Rydberg-valence interactions in the region of the Rydberg state equilibrium geometry. The Rydberg states of vinylidene present a great similarity with the acetylene isomer, concerning their quantum defects and Rydberg molecular orbital character. As in acetylene, strong s-d mixing is revealed in the n = 3 s-d supercomplex. Nevertheless, unlike in acetylene, the close-energy of the two vinylidene ionic cores 2A1 and 2B1 results into two overlapped Rydberg series. These Rydberg series exhibit local perturbations when an accidental degeneracy occurs between them and results in avoided crossings. In addition, some Δl = 1 (s-p and p-d) mixings arise for some Rydberg states and are rationalized in term of electrostatic interaction from the electric dipole moment of the ionic core. The strongest dipole moment of the 2 B1 cationic state also stabilizes the lowest members of the n = 3 Rydberg series converging to this excited state, as compared to the adjacent series converging toward the 2A1 ionic ground state. The overall energies of vinylidene Rydberg states lie above their acetylene counterpart. Finally, predictions for optical transitions in singlet vinylidene are suggested for further experimental spectroscopic characterization of vinylidene. © 2014 AIP Publishing LLC.
BibTeX:
@article{Boye-Peronne2014,
  author = {Boyé-Péronne, S. and Gauyacq, D. and Liévin, J.},
  title = {Theoretical description of electronically excited vinylidene up to 10 eV: First high level ab initio study of singlet valence and Rydberg states},
  journal = {Journal of Chemical Physics},
  year = {2014},
  volume = {141},
  article number = {174317},
  doi = {10.1063/1.4900875}
}
Abstract: In this paper we investigate a severe pollution episode that occurred in Beijing, Tianjin, and the Hebei province in January 2013. The episode was caused by the combination of anthropogenic emissions and a high-pressure system that trapped pollutants in the boundary layer. Using IASI (Infrared Atmospheric Sounding Interferometer) satellite measurements, high concentrations of key trace gases such as carbon monoxide (CO), sulfur dioxide (SO2), and ammonia (NH3) along with ammonium sulfate aerosol ((NH 4)2SO4) are found. We show that IASI is able to detect boundary layer pollution in case of large negative thermal contrast combined with high levels of pollution. Our findings demonstrate that anthropogenic key pollutants, such as CO and SO2, can be monitored by IASI in the North China Plain during wintertime in support of air quality evaluation and management. ©2013. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Boynard2014,
  author = {Boynard, A. and Clerbaux, C. and Clarisse, L. and Safieddine, S. and Pommier, M. and Van Damme, M. and Bauduin, S. and Oudot, C. and Hadji-Lazaro, J. and Hurtmans, D. and Coheur, P.-F.},
  title = {First simultaneous space measurements of atmospheric pollutants in the boundary layer from IASI: A case study in the North China Plain},
  journal = {Geophysical Research Letters},
  year = {2014},
  volume = {41},
  pages = {645-651},
  doi = {10.1002/2013GL058333}
}
Abstract: Volcanic eruptions emit plumes of ash and gases into the atmosphere, potentially at very high altitudes. Ash-rich plumes are hazardous for airplanes as ash is very abrasive and easily melts inside their engines. With more than 50 active volcanoes per year and the ever-increasing number of commercial flights, the safety of airplanes is a real concern. Satellite measurements are ideal for monitoring global volcanic activity and, in combination with atmospheric dispersion models, to track and forecast volcanic plumes. Here we present the Support to Aviation Control Service (SACS, http://sacs.aeronomie.be), which is a free online service initiated by the European Space Agency (ESA) for the near-real-time (NRT) satellite monitoring of volcanic plumes of SO2 and ash. It combines data from three ultraviolet (UV)-visible and three infrared (IR) spectrometers. The UV-vis sensors are the Ozone Monitoring Instrument (OMI) and the Global Ozone Monitoring Experiment-2 (GOME-2) on-board the two polar orbiting meteorological satellites (MetOp-A & MetOp-B) operated by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). The IR sensors are the Atmospheric InfraRed Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) on-board MetOp-A & MetOp-B. This new multi-sensor warning system of volcanic emissions is based on the selective detection of SO2 and ash. This system is optimised to avoid false alerts while at the same time limiting the number of notifications in case of large plumes. A successful rate with more than 95% of notifications corresponding to true volcanic activity is obtained by the SACS system. copyright © Author(s) 2014.
BibTeX:
@article{Brenot2014,
  author = {Brenot, H. and Theys, N. and Clarisse, L. and Van Geffen, J. and Van Gent, J. and Van Roozendael, M. and Van Der A, R. and Hurtmans, D. and Coheur, P.-F. and Clerbaux, C. and Valks, P. and Hedelt, P. and Prata, F. and Rasson, O. and Sievers, K. and Zehner, C.},
  title = {Support to aviation control service (SACS): An online service for near-real-time satellite monitoring of volcanic plumes},
  journal = {Natural Hazards and Earth System Sciences},
  year = {2014},
  volume = {14},
  pages = {1099-1123},
  doi = {10.5194/nhess-14-1099-2014}
}
Abstract: The isotope effects in Si- bound levels are studied using the multiconfiguration Hartree-Fock ab initio approach. Large-scale calculations are carried out for the 3p34So, 2Do, and 2Po multiplets of Si- and the 3p23P multiplet of Si. We predict an anomalous isotope shift on the electron affinity, dominated by the specific mass shift, with a value of -0.66(6) m-1 for the 30-28 isotope pair. We also report hyperfine-structure parameters for the studied multiplets. We provide the values of level electric-field gradients at the nucleus that could be of interest in a study of the metastable silicon isotopes. Relativistic corrections are estimated using nonrelativistic orbitals in the Breit-Pauli and fully relativistic frameworks. © 2014 American Physical Society.
BibTeX:
@article{Carette2014,
  author = {Carette, T. and Godefroid, M.R.},
  title = {Theoretical study of the isotope effects on the detachment thresholds of Si-},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2014},
  volume = {89},
  article number = {052513},
  doi = {10.1103/PhysRevA.89.052513}
}
Abstract: In the wake of the June 2011 Nabro eruption, large stratospheric plumes were observed by several instruments up to altitudes of 21 km, much higher than initial reported injection heights. It has been debated whether deep convection associated with the Asian Summer Monsoon anticyclone played a vital role in the vertical transport of the plume. Here we present a new and fast SO2 height retrieval algorithm for observations of the Infrared Atmospheric Sounding Interferometer (IASI). A comprehensive validation with forward trajectories and coincident CALIOP measurements is presented which indicates an accuracy better than 2 km for plumes below 20 km and SO2 columns up to the 1 DU level. We use this new product to analyse the Nabro eruption. Our findings indicate an initial plume located mainly between 15 and 17 km for which the lower parts underwent in succession rapid descent and uplift, within the Asian Monsoon anticyclone circulation, up to the stable thermal tropopause between 16 and 18 km, from where it slowly ascended further into the stratosphere. Evidence is presented that emissions in the first week of the eruption also contributed to the stratospheric sulfur input. This includes a second eruption between 15 and 17 km on the 16th and continuous emissions in the mid-troposphere of which some were also entrained and lifted within the anticyclonic circulation. © 2014 Author(s).
BibTeX:
@article{Clarisse2014,
  author = {Clarisse, L. and Coheur, P.-F. and Theys, N. and Hurtmans, D. and Clerbaux, C.},
  title = {The 2011 Nabro eruption, a SO2 plume height analysis using IASI measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2014},
  volume = {14},
  pages = {3095-3111},
  doi = {10.5194/acp-14-3095-2014}
}
Abstract: The B2Σ+-X2Σ+ (violet system) electronic transition of the 13C15N free radical was recorded with a Fourier transform spectrometer. The 0-0, 1-1, 1-0, 0-1 and 1-2 bands were rotationally analyzed to obtain spectroscopic constants. There have been no previous measurements of any electronic transitions for the 13C15N isotopologue. © 2014 Elsevier Inc. All rights reserved.
BibTeX:
@article{Colin2014,
  author = {Colin, R. and Bernath, P.F.},
  title = {Rotational analysis of the B2Σ+-X 2Σ+ transition of the 13C15N molecule},
  journal = {Journal of Molecular Spectroscopy},
  year = {2014},
  volume = {302},
  pages = {34-35},
  doi = {10.1016/j.jms.2014.06.006}
}
Abstract: This paper interprets tropical tropospheric nitric acid columns from the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument with a global chemical transport model (GEOS-Chem). GEOS-Chemand IASI columns generally agree over the tropical ocean to within 10%. However, the GEOS-Chem simulation underestimates IASI nitric acid over Southeast Asia by a factor of 2. The regional nitric acid bias is confirmed by comparing the GEOS-Chem simulation with additional satellite (High Resolution Dynamics Limb Sounder, Atmospheric Chemistry Experiment Fourier Transform Spectrometer) and aircraft (Pacific Exploratory Mission (PEM)-Tropics A and PEM-West B) observations of the middle and upper troposphere. This bias appears to be driven by the lightning NOx parameterization, both in terms of the magnitude of the NOx source and the ozone production efficiency of concentrated lightning NOx plumes. We tested a subgrid lightning plume parameterization and found that an ozone production efficiency of 15 mol/mol in lightning plumes over Southeast Asia in conjunction with an additional 0.5 Tg N would reduce the regional nitric acid bias from 92% to 6% without perturbing the rest of the tropics. Other sensitivity studies such as modified NOx yield per flash, increased altitude of lightning NOx emissions, decreased convective mass flux, or increased scavenging of nitric acid required unrealistic changes to reduce the bias. © 2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Cooper2014,
  author = {Cooper, M. and Martin, R.V. and Wespes, C. and Coheur, P.-F. and Clerbaux, C. and Murray, L.T.},
  title = {Tropospheric nitric acid columns from the IASI satellite instrument interpreted with a chemical transport model: Implications for parameterizations of nitric oxide production by lightning},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2014},
  volume = {119},
  pages = {10068-10079},
  doi = {10.1002/2014JD021907}
}
Abstract: Besides their strong contribution to weather forecast improvement through data assimilation, thermal infrared sounders onboard polar-orbiting platforms are now playing a key role for monitoring atmospheric composition changes. The Infrared Atmospheric Sounding Interferometer (IASI) instrument developed by the French space agency (CNES) and launched by EUMETSAT onboard the Metop satellite series is providing essential inputs for weather forecasting and pollution/climate monitoring owing to its smart combination of large horizontal swath, good spectral resolution and high radiometric performance. EUMETSAT is currently preparing the next polar-orbiting program (EPS-SG) with the Metop-SG satellite series that should be launched around 2020. In this framework, CNES is studying the concept of a new instrument, the IASI-New Generation (IASI-NG), characterized by an improvement of both spectral and radiometric characteristics as compared to IASI, with three objectives: (i) continuity of the IASI/Metop series; (ii) improvement of vertical resolution; and (iii) improvement of the accuracy and detection threshold for atmospheric and surface components. In this paper, we show that an improvement of spectral resolution and radiometric noise fulfil these objectives by leading to (i) a better vertical coverage in the lower part of the troposphere, thanks to the increase in spectral resolution; and (ii) an increase in the accuracy of the retrieval of several thermodynamic, climate and chemistry variables, thanks to the improved signal-to-noise ratio as well as less interference between the signatures of the absorbing species in the measured radiances. The detection limit of several atmospheric species is also improved. We conclude that IASI-NG has the potential to strongly benefit the numerical weather prediction, chemistry and climate communities now connected through the European GMES/Copernicus initiative. © Author(s) 2014.
BibTeX:
@article{Crevoisier2014,
  author = {Crevoisier, C. and Clerbaux, C. and Guidard, V. and Phulpin, T. and Armante, R. and Barret, B. and Camy-Peyret, C. and Chaboureau, J.-P. and Coheur, P.-F. and Crépeau, L. and Dufour, G. and Labonnote, L. and Lavanant, L. and Hadji-Lazaro, J. and Herbin, H. and Jacquinet-Husson, N. and Payan, S. and Péquignot, E. and Pierangelo, C. and Sellitto, P. and Stubenrauch, C.},
  title = {Towards IASI-New Generation (IASI-NG): Impact of improved spectral resolution and radiometric noise on the retrieval of thermodynamic, chemistry and climate variables},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {4367-4385},
  doi = {10.5194/amt-7-4367-2014}
}
Abstract: High resolution Fourier transform spectra of the 21102-00001 band of 12C16O2 near 3340cm-1 have been recorded and analyzed to extract isolated-line intensities and collisional parameters, and first-order line-mixing coefficients. Voigt, hard-collision Rautian and Sobel'man, and quadratic-speed-dependent Voigt profiles have been used. The line-mixing coefficients measured for the three branches have also been evaluated using an Energy-Corrected Sudden approach employing a symmetric metric in the Liouville space. These coefficients compare very favorably with the experimental results and estimations with an algorithm available in the literature. Results of straightforward ECS-modeling of complete band shapes have been compared to the recorded spectra and future improvements of this model required at subatmospheric pressures have been outlined. © 2014 Elsevier Ltd.
BibTeX:
@article{Daneshvar2014,
  author = {Daneshvar, L. and Földes, T. and Buldyreva, J. and Auwera, J.V.},
  title = {Infrared absorption by pure CO2 near 3340cm-1: Measurements and analysis of collisional coefficients and line-mixing effects at subatmospheric pressures},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2014},
  volume = {149},
  pages = {258-274},
  doi = {10.1016/j.jqsrt.2014.08.007}
}
Abstract: Extensive self-consistent multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations and subsequent relativistic configuration interaction calculations are performed for 262 states belonging to the 15 configurations 2s 22p2, 2s2p3, 2p4, 2s 22p3l, 2s2p23l, 2p33l and 2s22p4l(l = 0,1,2) in selected carbon-like ions from Ar XIII to Zn XXV. Electron correlation effects are accounted for through large configuration state function expansions. Calculated energy levels are compared with existing theoretical calculations and data from the Chianti and NIST databases. In addition, Landé gJ-factors and radiative electric dipole transition rates are given for all ions. The accuracy of the calculations are high enough to facilitate the identification of observed spectral lines. © 2014 ESO.
BibTeX:
@article{Ekman2014,
  author = {Ekman, J. and Jönsson, P. and Gustafsson, S. and Hartman, H. and Gaigalas, G. and Godefroid, M.R. and Froese Fischer, C.},
  title = {Calculations with spectroscopic accuracy: Energies, transition rates,and Lande gJ-factors in the carbon isoelectronic sequence from Ar XIII to Zn XXV},
  journal = {Astronomy and Astrophysics},
  year = {2014},
  volume = {564},
  article number = {A24},
  doi = {10.1051/0004-6361/201323163}
}
Abstract: Relativistic dipolar to hexadecapolar polarizabilities of the ground state and some excited states of hydrogenic atoms are calculated by using numerically exact energies and wave functions obtained from the Dirac equation with the Lagrange-mesh method. This approach is an approximate variational method taking the form of equations on a grid because of the use of a Gauss quadrature approximation. The partial polarizabilities conserving the absolute value of the quantum number κ are also numerically exact with small numbers of mesh points. The ones where |κ| changes are very accurate when using three different meshes for the initial and final wave functions and for the calculation of matrix elements. The polarizabilities of the n=2 excited states of hydrogenic atoms are also studied with a separate treatment of the final states that are degenerate at the nonrelativistic approximation. The method provides high accuracies for polarizabilities of a particle in a Yukawa potential and is applied to a hydrogen atom embedded in a Debye plasma. © 2014 American Physical Society.
BibTeX:
@article{Filippin2014,
  author = {Filippin, L. and Godefroid, M. and Baye, D.},
  title = {Relativistic polarizabilities with the Lagrange-mesh method},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2014},
  volume = {90},
  article number = {052520},
  doi = {10.1103/PhysRevA.90.052520}
}
Abstract: Jet-cooled spectra of 14NH3 and 15NH3 in natural abundance were recorded using cavity ring-down (CRDS, 6584-6670 cm-1) and cavity enhanced absorption (CEAS, 6530-6700 cm-1) spectroscopy. Line broadening effects in the CRDS spectrum allowed lines with J'-values between 0 and 3 to be identified. Intensity ratios in 14NH3 between the jet-cooled CRDS and literature room-temperature data from Sung et al. (J. Quant. Spectrosc. Radiat. Transfer, 113 (2012), 1066) further assisted the line assignments. Ground state combination differences were extensively used to support the assignments, providing reliable values for J, K and inversion symmetry of the ground state vibrational levels. CEAS data helped in this respect for the lowest J lines, some of which are saturated in the CRDS spectrum. Further information on a/s doublets arose from the observed spectral structures. Thirty-two transitions of 14NH3 were assigned in this way and a limited but significant number (19) of changes in the assignments results, compared to Sung et al. or to Cacciani et al. (J. Quant. Spectrosc. Radiat. Transfer, 113 (2012), 1084). Sixteen known and 25 new low-J transitions were identified for 15NH3 in the CRDS spectrum but the much scarcer literature information did not allow for any more refined assignment. The present line position measurements improve on literature values published for 15NH3 and on some line positions for 14NH3. © 2014 Taylor & Francis.
BibTeX:
@article{Foeldes2014a,
  author = {Földes, T. and Golebiowski, D. and Herman, M. and Softley, T.P. and Di Lonardo, G. and Fusina, L.},
  title = {Low-temperature high-resolution absorption spectrum of 14NH3 in the v1+v3 band region (1.51 μm)},
  journal = {Molecular Physics},
  year = {2014},
  volume = {112},
  pages = {2407-2418},
  doi = {10.1080/00268976.2014.904944}
}
Abstract: Cw-CRDS spectra of water-rare gas supersonic expansions were recorded between 7229 and 7262 cm-1. The effective absorption pathlength was about 1 km in jet-cooled gas and the resolution about 1 × 10-4cm-1. Many well-resolved structures are observed that could be assigned from experimental evidence to H2O-Ar/Kr bands. Eight broader unresolved features are more specifically reported and assigned to small H2O multimers, in good agreement and refining previous observations by Nizkorodov et al. [J. Chem. Phys. 122, 194316 (2005)]. Among these, the band at 7256.5 cm-1is shown to be a Q branch of the water dimer with accompanying R and very weak P lines. The band is assigned to a Ka= 0 → 1 transition and rotationally analyzed, leading to a restricted set of upper state rotational constants. The upper state lifetime (60 ± 3 ps) is extracted from the linewidths. © 2014 AIP Publishing LLC.
BibTeX:
@article{Foeldes2014,
  author = {Földes, T. and Vanfleteren, T. and Herman, M.},
  title = {Communication: A rotationally resolved (2OH) overtone band in the water dimer (H2O)2},
  journal = {Journal of Chemical Physics},
  year = {2014},
  volume = {141},
  article number = {111103},
  doi = {10.1063/1.4896163}
}
Abstract: We have recorded Fourier transform spectra of OCS between 6170 and 6680cm-1, and between 7700 and 8160cm-1 using a femto/OPO laser absorption source and cavity enhanced spectroscopy. Equivalent absorption path lengths varying between 7 and 13km were obtained depending on the specific spectral region. In the lower and higher energy ranges, 7 and 12 new bands were observed, respectively, while improved results were gained on those previously reported in the literature. Some of these data brought significant, new information on the rovibrational energy pattern in OCS that triggered an update of the latest published global polyad model (Rbaihi et al. J Mol Spectrosc 1998;191:32 [15]). The new fit includes for the first time all overtone data since published in the literature, covering the range 6200-13950cm-1, as well as all known lower energy ones. All data selected for the global analysis of carbonyl sulphide 16O12C32S are provided as supplementary information. The previous polyad model was extended to include the inter-polyad anharmonic k1113 and Coriolis C11222 interactions, leading to simultaneously deal with sets of nine interacting polyad matrices at a time, each polyad defined by N=2v1+v2+4v3 (with 1-3 the conventional normal modes in OCS). We have obtained a statistical agreement with all experimental data with an estimated standard deviation better than unity (σ=0.7568). The fit produced 141 molecular parameters, of which 4 concern the new inter-polyad resonances. They have been used to calculate effective rovibrational parameters for all sub-states up to more than 12,000cm-1, listed in a Depository (Appendix B). A list of line parameters, covering the measured spectral ranges and including line intensities determined using previously recorded Fourier transform spectra of the two strongest bands observed in the present work, was generated in HITRAN format. It is also provided as supplementary information. © 2014 Elsevier Ltd.
BibTeX:
@article{Golebiowski2014,
  author = {Golebiowski, D. and de Ghellinck d'Elseghem Vaernewijck, X. and Herman, M. and Auwera, J.V. and Fayt, A.},
  title = {High sensitivity (femto-FT-CEAS) spectra of carbonyl sulphide between 6200 and 8200cm-1, and new energy pattern in the global rovibrational analysis of 16O12C32S},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2014},
  volume = {149},
  pages = {184-203},
  doi = {10.1016/j.jqsrt.2014.07.005}
}
Abstract: The infrared absorption in the fundamental band of CO gas confined in porous silica xerogel has been recorded at room temperature for pressures between about 5 and 920 hPa using a high resolution Fourier transform spectrometer. The widths of individual lines are determined from fits of measured spectra and compared with ab initio predictions obtained from requantized classical molecular dynamics simulations. Good agreement is obtained from the low pressure regime where the line shapes are governed by molecule-wall collisions to high pressures where the influence of molecule-molecule interactions dominates. These results, together with those obtained with a simple analytical model, indicate that both mechanisms contribute in a practically additive way to the observed linewidths. They also confirm that a single collision of a molecule with a wall changes its rotational state. These results are of interest for the determination of some characteristics of the opened porosity of porous materials through optical soundings. © 2014 AIP Publishing LLC.
BibTeX:
@article{Hartmann2014,
  author = {Hartmann, J.-M. and Boulet, C. and Auwera, J.V. and El Hamzaoui, H. and Capoen, B. and Bouazaoui, M.},
  title = {Line broadening of confined CO gas: From molecule-wall to molecule-molecule collisions with pressure},
  journal = {Journal of Chemical Physics},
  year = {2014},
  volume = {140},
  article number = {064302},
  doi = {10.1063/1.4864205}
}
Abstract: Peak stratospheric chlorofluorocarbon (CFC) and other ozone depleting substance (ODS) concentrations were reached in the mid-to late 1990s. Detection and attribution of the expected recovery of the stratospheric ozone layer in an atmosphere with reduced ODSs as well as efforts to understand the evolution of stratospheric ozone in the presence of increasing greenhouse gases are key current research topics. These require a critical examination of the ozone changes with an accurate knowledge of the spatial (geographical and vertical) and temporal ozone response. For such an examination, it is vital that the quality of the measurements used be as high as possible and measurement uncertainties well quantified.

In preparation for the 2014 United Nations Environment Programme (UNEP)/World Meteorological Organization (WMO) Scientific Assessment of Ozone Depletion, the SPARC/IO3C/IGACO-O3/NDACC (SI2N) Initiative was designed to study and document changes in the global ozone profile distribution. This requires assessing long-term ozone profile data sets in regards to measurement stability and uncertainty characteristics. The ultimate goal is to establish suitability for estimating long-term ozone trends to contribute to ozone recovery studies. Some of the data sets have been improved as part of this initiative with updated versions now available.

This summary presents an overview of stratospheric ozone profile measurement data sets (ground and satellite based) available for ozone recovery studies. Here we document measurement techniques, spatial and temporal coverage, vertical resolution, native units and measurement uncertainties. In addition, the latest data versions are briefly described (including data version updates as well as detailing multiple retrievals when available for a given satellite instrument). Archive location information for each data set is also given. © Author(s) 2014.
BibTeX:
@article{Hassler2014,
  author = {Hassler, B. and Petropavlovskikh, I. and Staehelin, J. and August, T. and Bhartia, P.K. and Clerbaux, C. and Degenstein, D. and De Mazière, M. and Dinelli, B.M. and Dudhia, A. and Dufour, G. and Frith, S.M. and Froidevaux, L. and Godin-Beekmann, S. and Granville, J. and Harris, N.R.P. and Hoppel, K. and Hubert, D. and Kasai, Y. and Kurylo, M.J. and Kyrölä, E. and Levelt, P.F. and McElroy, C.T. and McPeters, R.D. and Munro, R. and Nakajima, H. and Parrish, A. and Raspollini, P. and Remsberg, E.E. and Rosenlof, K.H. and Rozanov, A. and Sano, T. and Sasano, Y. and Shiotani, M. and Smit, H.G.J. and Stiller, G. and Tamminen, J. and Tarasick, D.W. and Urban, J. and Van Der A, R.J. and Veefkind, J.P. and Vigouroux, C. and Von Clarmann, T. and Von Savigny, C. and Walker, K.A. and Weber, M. and Wild, J. and Zawodny, J.M.},
  title = {Past changes in the vertical distribution of ozone – Part 1: Measurement techniques, uncertainties and availability},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {1395-1427},
  doi = {10.5194/amt-7-1395-2014}
}
Abstract: Gravity waves are an important driver for the atmospheric circulation and have substantial impact on weather and climate. Satellite instruments offer excellent opportunities to study gravity waves on a global scale. This study focuses on observations from the Atmospheric Infrared Sounder (AIRS) onboard the National Aeronautics and Space Administration Aqua satellite and the Infrared Atmospheric Sounding Interferometer (IASI) onboard the European MetOp satellites. The main aim of this study is an intercomparison of stratospheric gravity wave observations of both instruments. In particular, we analyzed AIRS and IASI 4.3 μm brightness temperature measurements, which directly relate to stratospheric temperature. Three case studies showed that AIRS and IASI provide a clear and consistent picture of the temporal development of individual gravity wave events. Statistical comparisons based on a 5-year period of measurements (2008-2012) showed similar spatial and temporal patterns of gravity wave activity. However, the statistical comparisons also revealed systematic differences of variances between AIRS and IASI that we attribute to the different spatial measurement characteristics of both instruments. We also found differences between day- and nighttime data that are partly due to the local time variations of the gravity wave sources. While AIRS has been used successfully in many previous gravity wave studies, IASI data are applied here for the first time for that purpose. Our study shows that gravity wave observations from different hyperspectral infrared sounders such as AIRS and IASI can be directly related to each other, if instrument-specific characteristics such as different noise levels and spatial resolution and sampling are carefully considered. The ability to combine observations from different satellites provides an opportunity to create a long-term record, which is an exciting prospect for future climatological studies of stratospheric gravity wave activity. © Author(s) 2014.
BibTeX:
@article{Hoffmann2014,
  author = {Hoffmann, L. and Alexander, M.J. and Clerbaux, C. and Grimsdell, A.W. and Meyer, C.I. and Rößler, T. and Tournier, B.},
  title = {Intercomparison of stratospheric gravity wave observations with AIRS and IASI},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {4517-4537},
  doi = {10.5194/amt-7-4517-2014}
}
Abstract: The electronic structure of DNA is determined by its nucleotide sequence, which is for instance exploited in molecular electronics. Here we demonstrate that also the DNA strand breakage induced by low-energy electrons (18 eV) depends on the nucleotide sequence. To determine the absolute cross sections for electron induced single strand breaks in specific 13 mer oligonucleotides we used atomic force microscopy analysis of DNA origami based DNA nanoarrays. We investigated the DNA sequences 5′-TT(XYX) 3 TT with X = A, G, C and Y = T, BrU 5-bromouracil and found absolute strand break cross sections between 2.66 · 10-14 cm2 and 7.06 · 10-14 cm2. The highest cross section was found for 5 2-TT(ATA) 3 TT and 5 2-TT(ABrUA) 3 TT, respectively. BrU is a radiosensitizer, which was discussed to be used in cancer radiation therapy. The replacement of T by BrU into the investigated DNA sequences leads to a slight increase of the absolute strand break cross sections resulting in sequence-dependent enhancement factors between 1.14 and 1.66. Nevertheless, the variation of strand break cross sections due to the specific nucleotide sequence is considerably higher. Thus, the present results suggest the development of targeted radiosensitizers for cancer radiation therapy.
BibTeX:
@article{Keller2014,
  author = {Keller, A. and Rackwitz, J. and Cauët, E. and Liévin, J. and Körzdörfer, T. and Rotaru, A. and Gothelf, K.V. and Besenbacher, F. and Bald, I.},
  title = {Sequence dependence of electron-induced DNA strand breakage revealed by DNA nanoarrays},
  journal = {Scientific Reports},
  year = {2014},
  volume = {4},
  article number = {7391},
  doi = {10.1038/srep07391}
}
Abstract: A method to constrain carbon dioxide (CO2) emissions from open biomass burning by using satellite observations of co-emitted species and a chemistry-transport model (CTM) is proposed and applied to the case of wildfires in Siberia. CO2emissions are assessed by means of an emission model assuming a direct relationship between the biomass burning rate (BBR) and the fire radiative power (FRP) derived from MODIS measurements. The key features of the method are (1) estimating the FRP-to-BBR conversion factors (α) for different vegetative land cover types by assimilating the satellite observations of co-emitted species into the CTM, (2) optimal combination of the estimates of α derived independently from satellite observations of different species (CO and aerosol in this study), and (3) estimation of the diurnal cycle of the fire emissions directly from the FRP measurements. Values of α for forest and grassland fires in Siberia and their uncertainties are estimated using the Infrared Atmospheric Sounding Interferometer (IASI) carbon monoxide (CO) retrievals and MODIS aerosol optical depth (AOD) measurements combined with outputs from the CHIMERE mesoscale chemistry-transport model. The constrained CO emissions are validated through comparison of the respective simulations with independent data of ground-based CO measurements at the ZOTTO site. Using our optimal regional-scale estimates of the conversion factors (which are found to be in agreement with earlier published estimates obtained from local measurements of experimental fires), the total CO2emissions from wildfires in Siberia in 2012 are estimated to be in the range from 280 to 550 Tg C, with the optimal (maximum likelihood) value of 392 Tg C. Sensitivity test cases featuring different assumptions regarding the injection height and diurnal variations of emissions indicate that the derived estimates of the total CO2emissions in Siberia are robust with respect to the modeling options (the different estimates vary within less than 15% of their magnitude). The CO2emission estimates obtained for several years are compared with independent estimates provided by the GFED3.1 and GFASv1.0 global emission inventories. It is found that our "top-down" estimates for the total annual biomass burning CO2emissions in the period from 2007 to 2011 in Siberia are by factors of 2.5 and 1.8 larger than the respective bottom-up estimates; these discrepancies cannot be fully explained by uncertainties in our estimates. There are also considerable differences in the spatial distribution of the different emission estimates; some of those differences have a systematic character and require further analysis. © Author(s) 2014. CC Attribution 3.0 License.
BibTeX:
@article{Konovalov2014,
  author = {Konovalov, I.B. and Berezin, E.V. and Ciais, P. and Broquet, G. and Beekmann, M. and Hadji-Lazaro, J. and Clerbaux, C. and Andreae, M.O. and Kaiser, J.W. and Schulze, E.-D.},
  title = {Constraining CO2emissions from open biomass burning by satellite observations of co-emitted species: A method and its application to wildfires in Siberia},
  journal = {Atmospheric Chemistry and Physics},
  year = {2014},
  volume = {14},
  pages = {10383-10410},
  doi = {10.5194/acp-14-10383-2014}
}
Abstract: The European Space Agency project Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards, was introduced after the eruption of the Icelandic volcano Eyjafjallajökull in the spring of 2010 to facilitate the development of an optimal End­to­End System for Volcanic Ash Plume Monitoring and Prediction. The Eyjafjallajökull plume drifted towards Europe and caused major disruptions of European air traffic for several weeks affecting the everyday life of millions of people. The limitations in volcanic plume monitoring and prediction capabilities gave birth to this observational system which is based on comprehensive satellite­derived ash plume and sulphur dioxide [SO2] level estimates, as well as a widespread validation using supplementary satellite, aircraft and ground­based measurements. Inter­comparison of the volcanic total SO2 column and plume height observed by GOME­2/Metop­A and IASI/Metop­A are shown before, during and after the Eyjafjallajökull 2010 eruptions as well as for the 2011 Grímsvötn eruption. Co­located ground­based Brewer Spectro­photometer data extracted from the World Ozone and Ultraviolet Radiation Data Centre for de Bilt, the Netherlands, are also compared to the different satellite estimates. Promising agreement is found for the two different types of instrument for the SO2 columns with linear regression coefficients ranging around from 0.64 when comparing the different instruments and 0.85 when comparing the two different IASI algorithms. The agreement for the plume height is lower, possibly due to the major differences between the height retrieval part of the GOME2 and IASI algorithms. The comparisons with the Brewer ground­based station in de Bilt, The Netherlands show good qualitative agreement for the peak of the event however stronger eruptive signals are required for a longer quantitative comparison. © 2014, Editrice Compositori s.r.l., All rights reserved.
BibTeX:
@article{Koukouli2014,
  author = {Koukouli, M.E. and Clarisse, L. and Carboni, E. and Van Gent, J. and Spinetti, C. and Balis, D. and Dimopoulos, S. and Grainger, R. and Theys, N. and Tampellini, L. and Zehner, C.},
  title = {Intercomparison of Metop-A SO2 measurements during the 2010- 2011 Icelandic eruptions},
  journal = {Annals of Geophysics},
  year = {2014},
  volume = {57},
  article number = {A007},
  doi = {10.4401/ag-6613}
}
Abstract: We present the results of an extensive validation program of the most recent version of ozone vertical profiles retrieved with the IMK/IAA (Institute for Meteorology and Climate Research/Instituto de Astrofísica de Andalucía) MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) research level 2 processor from version 5 spectral level 1 data. The time period covered corresponds to the reduced spectral resolution period of the MIPAS instrument, i.e., January 2005-April 2012. The comparison with satellite instruments includes all post-2005 satellite limb and occultation sensors that have measured the vertical profiles of tropospheric and stratospheric ozone: ACE-FTS, GOMOS, HALOE, HIRDLS, MLS, OSIRIS, POAM, SAGE II, SCIAMACHY, SMILES, and SMR. In addition, balloon-borne MkIV solar occultation measurements and ground-based Umkehr measurements have been included, as well as two nadir sensors: IASI and SBUV. For each reference data set, bias determination and precision assessment are performed. Better agreement with reference instruments than for the previous data version, V5R-O3-220 (Laeng et al., 2014), is found: the known high bias around the ozone vmr (volume mixing ratio) peak is significantly reduced and the vertical resolution at 35 km has been improved. The agreement with limb and solar occultation reference instruments that have a known small bias vs. ozonesondes is within 7% in the lower and middle stratosphere and 5% in the upper troposphere. Around the ozone vmr peak, the agreement with most of the satellite reference instruments is within 5%; this bias is as low as 3% for ACE-FTS, MLS, OSIRIS, POAM and SBUV. © Author(s) 2014.
BibTeX:
@article{Laeng2014,
  author = {Laeng, A. and Grabowski, U. and Von Clarmann, T. and Stiller, G. and Glatthor, N. and Höpfner, M. and Kellmann, S. and Kiefer, M. and Linden, A. and Lossow, S. and Sofieva, V. and Petropavlovskikh, I. and Hubert, D. and Bathgate, T. and Bernath, P. and Boone, C.D. and Clerbaux, C. and Coheur, P. and Damadeo, R. and Degenstein, D. and Frith, S. and Froidevaux, L. and Gille, J. and Hoppel, K. and Mchugh, M. and Kasai, Y. and Lumpe, J. and Rahpoe, N. and Toon, G. and Sano, T. and Suzuki, M. and Tamminen, J. and Urban, J. and Walker, K. and Weber, M. and Zawodny, J.},
  title = {Validation of MIPAS IMK/IAA V5R-O3-224 ozone profiles},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {3971-3987},
  doi = {10.5194/amt-7-3971-2014}
}
Abstract: We illustrate computational aspects of the calculation of the potential energy surfaces of small (up to five atoms) van der Waals complexes with high-level quantum chemistry techniques such as the CCSD(T) method with extended basis sets. We discuss the compromise between the required accuracy and the computational time. Further, we show how these potential energy surfaces can be fitted and used in dynamical calculations such as non-reactive inelastic scattering. © 2014 AIP Publishing LLC.
BibTeX:
@conference{Loreau2014b,
  author = {Loreau, J.},
  title = {Structure and dynamics of small van der Waals complexes},
  journal = {AIP Conference Proceedings},
  year = {2014},
  volume = {1618},
  pages = {585-588},
  doi = {10.1063/1.4897805}
}
Abstract: A new, four-dimensional potential energy surface for the interaction of NH3 and ND3 with Ar is computed using the coupled-cluster method with single, double, and perturbative triple excitations and large basis sets. The umbrella motion of the ammonia molecule is explicitly taken into account. The bound states of both NH3-Ar and ND3-Ar are calculated on this potential for total angular momentum values from J = 0 to 10, with the inclusion of Coriolis interactions. The energies and splittings of the rovibrational levels are in excellent agreement with the extensive high-resolution spectroscopic data accumulated over the years in the infrared and microwave regions for both complexes, which demonstrates the quality of the potential energy surface. © 2014 AIP Publishing LLC.
BibTeX:
@article{Loreau2014,
  author = {Loreau, J. and Liévin, J. and Scribano, Y. and Van Der Avoird, A.},
  title = {Potential energy surface and bound states of the NH3-Ar and ND3-Ar complexes},
  journal = {Journal of Chemical Physics},
  year = {2014},
  volume = {141},
  article number = {224303},
  doi = {10.1063/1.4903047}
}
Abstract: The cross section for charge transfer in proton-helium collisions has been computed in the energy range from 10eV/u up to 10 MeV/u. Four different methods (full quantal time-independent and time-dependent methods, molecular and atomic basis set semi-classical approaches) valid in different energy regimes have been used to calculate the partial and total cross section for single-electron capture. The results are compared with previous theoretical calculations and experimental measurements and the different theoretical methods used are shown to be complementary for describing the charge transfer reaction. A fit of the cross section, valid for collision energies from 10eV/u up to 10 MeV/u is presented based on these results. © 2014 IOP Publishing Ltd.
BibTeX:
@article{Loreau2014a,
  author = {Loreau, J. and Ryabchenko, S. and Vaeck, N.},
  title = {Charge transfer in proton-helium collisions from low to high energy},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2014},
  volume = {47},
  article number = {135204},
  doi = {10.1088/0953-4075/47/13/135204}
}
Abstract: The absorption spectrum of acetylene has been recorded at room temperature (297 K) using high-sensitivity cavity ring-down spectroscopy (αmin ∼ 5×10-11 cm-1) in the 5851 and 6341 cm-1 interval corresponding to a region of very weak absorption. A list of about 10,700 absorption features with estimated absolute line intensities was constructed. The smallest intensities are of the order of 5×10-29 cm molecule-1. The line list includes about 2500 absorption lines of ethylene present at the ppm level in the acetylene sample and identified on the basis of a high-resolution Fourier transform spectrum specifically recorded. A total of more than 2700 lines of 12C2H2 were rovibrationally assigned in comparison with accurate predictions provided by a global effective operator model. Overall, the present effort adds about 2260 new assignments to the set of about 500 assigned transitions available in the literature. The new assignments correspond to 45 new bands and 17 already-known bands, for which additional J lines were assigned. Spectroscopic parameters were derived for the upper vibrational levels from a band by band fit of the line positions (typical root mean square deviation values are of the order of 0.001 cm-1). A few of the analysed bands were found to be affected by rovibrational perturbations, which are discussed. The new data will be valuable to refine the parameters of the global effective Hamiltonian and dipole moments of 12C2H2. © 2014 Taylor & Francis.
BibTeX:
@article{Lyulin2014,
  author = {Lyulin, O.M. and Mondelain, D. and Béguier, S. and Kassi, S. and Vander Auwera, J. and Campargue, A.},
  title = {High-sensitivity CRDS absorption spectroscopy of acetylene between 5851 and 6341 cm-1},
  journal = {Molecular Physics},
  year = {2014},
  volume = {112},
  pages = {2433-2444},
  doi = {10.1080/00268976.2014.906677}
}
Abstract: The advent of high-resolution spectrographs and detailed stellar atmosphere modelling has strengthened the need for accurate molecular data. Carbon-enhanced metal-poor (CEMP) stars spectra are interesting objects with which to study transitions from the CH molecule. We combine programs for spectral analysis of molecules and stellar-radiative transfer codes to build an extensive CH linelist, including predissociation broadening as well as newly identified levels. We show examples of strong predissociation CH lines in CEMP stars, and we stress the important role played by the CH features in the Bond-Neff feature depressing the spectra of barium stars by as much as 0.2 mag in the λ = 3000-5500 Å range. Because of the extreme thermodynamic conditions prevailing in stellar atmospheres (compared to the laboratory), molecular transitions with high energy levels can be observed. Stellar spectra can thus be used to constrain and improve molecular data. © 2014 ESO.
BibTeX:
@article{Masseron2014,
  author = {Masseron, T. and Plez, B. and Van Eck, S. and Colin, R. and Daoutidis, I. and Godefroid, M. and Coheur, P.-F. and Bernath, P. and Jorissen, A. and Christlieb, N.},
  title = {CH in stellar atmospheres: An extensive linelist},
  journal = {Astronomy and Astrophysics},
  year = {2014},
  volume = {571},
  article number = {A47},
  doi = {10.1051/0004-6361/201423956}
}
Abstract: Modeling the transport of volcanic ash and gases released during volcanic eruptions is crucially dependent on knowledge of the source term of the eruption, that is, the source strength as a function of altitude and time. For the first time, an inversion method is used to estimate the source terms of both volcanic sulfur dioxide (SO2) and ash. It was applied to the explosive volcanic eruption of Grímsvötn, Iceland, in May 2011. The method uses input from the particle dispersion model, FLEXPART (flexible particle dispersion model), a priori source estimates, and satellite observations of SO2 or ash total columns from Infrared Atmospheric Sounding Interferometer to separately obtain the source terms for volcanic SO2 and fine ash. The estimated source terms show that SO2 was emitted mostly to high altitudes (5 to 13 km) during about 18 h (22 May, 00-18 UTC) while fine ash was emitted mostly to low altitudes (below 4 km) during roughly 24 h (22 May 06 UTC to 23 May 06 UTC). FLEXPART simulations using the estimated source terms show a clear separation of SO2 (transported mostly northwestward) and the fine ash (transported mostly southeastward). This corresponds well with independent satellite observations and measured aerosol mass concentrations and lidar measurements at surface stations in Scandinavia. Aircraft measurements above Iceland and Germany confirmed that the ash was located in the lower atmosphere. This demonstrates that the inversion method, in this case, is able to distinguish between emission heights of SO2 and ash and can capture resulting differences in transport patterns. Key Points Ash and SO2 source terms estimated using inverse techniques and satellite data The transport and separation of ash and SO2 are modeled Model simulations correspond well with a range of independent observations ©2014. The Authors.
BibTeX:
@article{Moxnes2014,
  author = {Moxnes, E.D. and Kristiansen, N.I. and Stohl, A. and Clarisse, L. and Durant, A. and Weber, K. and Vogel, A.},
  title = {Separation of ash and sulfur dioxide during the 2011 Grímsvötn eruption},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2014},
  volume = {119},
  pages = {7477-7501},
  doi = {10.1002/2013JD021129}
}
Abstract: Energy levels, normal and specific mass shift parameters as well as electronic densities at the nucleus are reported for numerous states along the beryllium, boron, carbon, and nitrogen isoelectronic sequences. Combined with nuclear data, these electronic parameters can be used to determine values of level and transition isotope shifts. The calculation of the electronic parameters is done using first-order perturbation theory with relativistic configuration interaction wavefunctions that account for valence, core-valence, and core-core correlation effects as zero-order functions. Results are compared with experimental and other theoretical values, when available. © 2014 Elsevier Inc.
BibTeX:
@article{Naze2014,
  author = {Nazé, C. and Verdebout, S. and Rynkun, P. and Gaigalas, G. and Godefroid, M. and Jönsson, P.},
  title = {Isotope shifts in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations},
  journal = {Atomic Data and Nuclear Data Tables},
  year = {2014},
  volume = {100},
  pages = {1197-1249},
  doi = {10.1016/j.adt.2014.02.004}
}
Abstract: We apply the Tropospheric Emission Spectrometer (TES) ozone retrieval algorithm to Infrared Atmospheric Sounding Instrument (IASI) radiances and characterise the uncertainties and information content of the retrieved ozone profiles. This study focuses on mid-latitudes for the year 2008. We validate our results by comparing the IASI ozone profiles to ozone sondes. In the sonde comparisons, we find a negative bias (1-10%) in the IASI profiles in the lower to mid-troposphere and a positive bias (up to 14%) in the upper troposphere/lower stratosphere (UTLS) region. For the described cases, the degrees of freedom for signal are on average 3.2, 0.3, 0.8, and 0.9 for the columns 0 km - top of atmosphere, (0-6), (0-11), and (8-16) km, respectively. We find that our biases with respect to sondes and our degrees of freedom for signal for ozone are comparable to previously published results from other IASI ozone algorithms. In addition to evaluating biases, we validate the retrieval errors by comparing predicted errors to the sample covariance matrix of the IASI observations themselves. For the predicted versus empirical error comparison, we find that these errors are consistent and that the measurement noise and the interference of temperature and water vapour on the retrieval together mostly explain the empirically derived random errors. In general, the precision of the IASI ozone profiles is better than 20%. © 2014 Author(s).
BibTeX:
@article{Oetjen2014,
  author = {Oetjen, H. and Payne, V.H. and Kulawik, S.S. and Eldering, A. and Worden, J. and Edwards, D.P. and Francis, G.L. and Worden, H.M. and Clerbaux, C. and Hadji-Lazaro, J. and Hurtmans, D.},
  title = {Extending the satellite data record of tropospheric ozone profiles from Aura-TES to MetOp-IASI: Characterisation of optimal estimation retrievals},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {4223-4236},
  doi = {10.5194/amt-7-4223-2014}
}
Abstract: This study presents the joint H2 16O and HDO retrieval from Infrared Atmospheric Sounding Interferometer (IASI) spectra over western Siberia. IASI is an instrument on board the MetOp-A European satellite. The global coverage of the instrument and the good signal-to-noise ratio allow us to provide information on δD over this remote region. We show that IASI measurements may be used to estimate integrated δD between the surface and 3 km altitude or from 1 to 5 km depending on the thermal contrast, with observational errors lower than 4% and 7 %, respectively. The retrieved data are compared to simulations from an isotopic general circulation model, LMDZ-iso for 2011. The satellite measurements and the model agree well and they reproduce well the seasonal and day-to-day variations for δD, presenting a good correlation (r up to 0.8 with the smoothed data in summer). The IASI-based retrievals also show the seasonal variation of the specific humidity in both altitude ranges. © Author(s) 2014.
BibTeX:
@article{Pommier2014,
  author = {Pommier, M. and Lacour, J.-L. and Risi, C. and Bréon, F.M. and Clerbaux, C. and Coheur, P.-F. and Gribanov, K. and Hurtmans, D. and Jouzel, J. and Zakharov, V.},
  title = {Observation of tropospheric δd by IASI over western Siberia: Comparison with a general circulation model},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {1581-1595},
  doi = {10.5194/amt-7-1581-2014}
}
Abstract: We assess the pros and cons of a large panel of DFT exchange-correlation functionals for the prediction of the electronic structure of hydrogen-rich peptide radicals formed after electron attachment on a protonated peptide. Indeed, despite its importance in the understanding of the chemical changes associated with the reduction step, the question of the attachment site of an electron and, more generally, of the reduced species formed in the gas phase through electron-induced dissociation (ExD) processes in mass spectrometry is still a matter of debate. For hydrogen-rich peptide radicals in which several positive groups and low-lying π* orbitals can capture the incoming electron in ExD, inclusion of full Hartree-Fock exchange at long-range interelectronic distance is a prerequisite for an accurate description of the electronic states, thereby excluding several popular exchange-correlation functionals, e.g., B3LYP, M06-2X, or CAM-B3LYP. However, we show that this condition is not sufficient by comparing the results obtained with asymptotically correct range-separated hybrids (M11, LC-BLYP, LC-BPW91, ωB97, ωB97X, and ωB97X-D) and with reference CASSCF-MRCI and EOM-CCSD calculations. The attenuation parameter ω significantly tunes the spin density distribution and the excited states vertical energies. The investigated model structures, ranging from methylammonium to hexapeptide, allow us to obtain a description of the nature and energy of the electronic states, depending on (i) the presence of hydrogen bond(s) around the cationic site(s), (ii) the presence of π* molecular orbitals (MOs), and (iii) the selected DFT approach. It turns out that, in the present framework, LC-BLYP and ωB97 yields the most accurate results. © 2014 American Chemical Society.
BibTeX:
@article{Riffet2014,
  author = {Riffet, V. and Jacquemin, D. and Cauët, E. and Frison, G.},
  title = {Benchmarking DFT and TD-DFT functionals for the ground and excited states of hydrogen-rich peptide radicals},
  journal = {Journal of Chemical Theory and Computation},
  year = {2014},
  volume = {10},
  pages = {3308-3318},
  doi = {10.1021/ct5004912}
}
Abstract: We investigate the interaction of ground and excited states of silver atom with all the noble gases, including helium. Born-Oppenheimer potential energy curves are calculated with quantum chemical techniques and spin-orbit effects in the excited states are included. We compare with experimentally available spectroscopic data, as well as previous calculations. The assignment of vibrational levels in the one experiment we compare with, may have to shift up by one unit. © Published under licence by IOP Publishing Ltd.
BibTeX:
@article{Sadeghpour2014,
  author = {Sadeghpour, H.R. and Loreau, J. and Dalgarno, A.},
  title = {Interaction of Ag(5s) and Ag(5p) with noble gas atoms},
  journal = {Journal of Physics: Conference Series},
  year = {2014},
  volume = {488},
  article number = {122006},
  doi = {10.1088/1742-6596/488/12/122006}
}
Abstract: Over the Mediterranean region, elevated tropospheric ozone (O3) values are recorded, especially in summer. We use the thermal Infrared Atmospheric Sounding Interferometer (IASI) and the Weather Research and Forecasting Model with Chemistry (WRF-Chem) to understand and interpret the factors and emission sources responsible for the high O3concentrations observed in the Mediterranean troposphere. Six years (2008-2013) of IASI data have been analyzed and results show consistent maxima during summer, with an increase of up to 22% in the [0-8] km O3column in the eastern part of the basin compared to the middle of the basin. We focus on summer 2010 to investigate the processes that contribute to these summer maxima. Using two modeled O3tracers (inflow to the model domain and local anthropogenic emissions), we show that, between the surface and 2 km, O3is mostly formed from anthropogenic emissions, while above 4 km it is mostly transported from outside the domain or from stratospheric origins. Evidence of stratosphere-to-troposphere exchange (STE) events in the eastern part of the basin is shown, and corresponds to a low water vapor mixing ratio and high potential vorticity. © 2014 Author(s).
BibTeX:
@article{Safieddine2014,
  author = {Safieddine, S. and Boynard, A. and Coheur, P.-F. and Hurtmans, D. and Pfister, G. and Quennehen, B. and Thomas, J.L. and Raut, J.-C. and Law, K.S. and Klimont, Z. and Hadji-Lazaro, J. and George, M. and Clerbaux, C.},
  title = {Summertime tropospheric ozone assessment over the Mediterranean region using the thermal infrared IASI/MetOp sounder and the WRF-Chem model},
  journal = {Atmospheric Chemistry and Physics},
  year = {2014},
  volume = {14},
  pages = {10119-10131},
  doi = {10.5194/acp-14-10119-2014}
}
BibTeX:
@article{Softley2014,
  author = {Softley, T.P. and Császár, A.G. and De Natale, P. and Herman, M. and Quack, M.},
  title = {Special issue: 23rd Colloquium on High Resolution Molecular Spectroscopy},
  journal = {Molecular Physics},
  year = {2014},
  volume = {112},
  pages = {2373},
  doi = {10.1080/00268976.2014.943982}
}
Abstract: Mt. Etna volcano in Italy is one of the most active degassing volcanoes worldwide, emitting a mean of 1.7 Mt/year of Sulphur Dioxide (SO2) in quiescent periods. In this work, SO2 measurements retrieved by Moderate Resolution Imaging Spectroradiometer (MODIS), hyper-spectral Infrared Atmospheric Sounding Interferometer (IASI) and the second Global Ozone Monitoring Experiment (GOME-2) data are compared with the ground-based data from the FLux Automatic MEasurement monitoring network (FLAME). Among the eighteen lava fountain episodes occurring at Mt. Etna in 2011, the 10 April paroxysmal event has been selected as a case-study for the simultaneous observation of the SO2 cloud by satellite and ground-based sensors. For each data-set two retrieval techniques were adopted and the measurements of SO2 mass and flux with their respective uncertainty were obtained. With respect to the FLAME SO2 mass of 4.5 Gg, MODIS, IASI and GOME-2 differ by about 10%, 15% and 30%, respectively. The SO2 flux correlation coefficient between MODIS and FLAME is 0.84. All the retrievals within the respective errors are in agreement with the ground-based measurements supporting the validity of these space measurements. © 2014, Editrice Compositori s.r.l. All rights reserved.
BibTeX:
@article{Spinetti2014,
  author = {Spinetti, C. and Salerno, G.G. and Caltabiano, T. and Carboni, E. and Clarisse, L. and Corradini, S. and Grainger, R.G. and Hedelt, P.A. and Koukouli, M.E. and Merucci, L. and Siddans, R. and Tampellini, L. and Theys, N. and Valks, P. and Zehner, C.},
  title = {Volcanic SO2 by UV-TIR satellite retrievals: Validation by using ground-based network at Mt. Etna},
  journal = {Annals of Geophysics},
  year = {2014},
  volume = {57},
  doi = {10.4401/ag-6641}
}
Abstract: Despite the developments in the global modelling of chemistry and of the parameterization of the physical processes, carbon monoxide (CO) concentrations remain underestimated during Northern Hemisphere (NH) winter by most state-of-the-art chemistry transport models. The consequential model bias can in principle originate from either an underestimation of CO sources or an overestimation of its sinks. We address both the role of surface sources and sinks with a series of MOZART (Model for Ozone And Related Tracers) model sensitivity studies for the year 2008 and compare our results to observational data from ground-based stations, satellite observations, and vertical profiles from measurements on passenger aircraft. In our base case simulation using MACCity (Monitoring Atmospheric Composition and Climate project) anthropogenic emissions, the near-surface CO mixing ratios are underestimated in the Northern Hemisphere by more than 20 ppb from December to April, with the largest bias of up to 75 ppb over Europe in January. An increase in global biomass burning or biogenic emissions of CO or volatile organic compounds (VOCs) is not able to reduce the annual course of the model bias and yields concentrations over the Southern Hemisphere which are too high. Raising global annual anthropogenic emissions with a simple scaling factor results in overestimations of surface mixing ratios in most regions all year round. Instead, our results indicate that anthropogenic CO and, possibly, VOC emissions in the MACCity inventory are too low for the industrialized countries only during winter and spring. Reasonable agreement with observations can only be achieved if the CO emissions are adjusted seasonally with regionally varying scaling factors. A part of the model bias could also be eliminated by exchanging the original resistance-type dry deposition scheme with a parameterization for CO uptake by oxidation from soil bacteria and microbes, which reduces the boreal winter dry deposition fluxes. The best match to surface observations, satellite retrievals, and aircraft observations was achieved when the modified dry deposition scheme was combined with increased wintertime road traffic emissions over Europe and North America (factors up to 4.5 and 2, respectively). One reason for the apparent underestimation of emissions may be an exaggerated downward trend in the Representative Concentration Pathway (RCP) 8.5 scenario in these regions between 2000 and 2010, as this scenario was used to extrapolate the MACCity emissions from their base year 2000. This factor is potentially amplified by a lack of knowledge about the seasonality of emissions. A methane lifetime of 9.7 yr for our basic model and 9.8 yr for the optimized simulation agrees well with current estimates of global OH, but we cannot fully exclude a potential effect from errors in the geographical and seasonal distribution of OH concentrations on the modelled CO. © Author(s) 2014. CC Attribution 3.0 License.
BibTeX:
@article{Stein2014,
  author = {Stein, O. and Schultz, M.G. and Bouarar, I. and Clark, H. and Huijnen, V. and Gaudel, A. and George, M. and Clerbaux, C.},
  title = {On the wintertime low bias of Northern Hemisphere carbon monoxide found in global model simulations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2014},
  volume = {14},
  pages = {9295-9316},
  doi = {10.5194/acp-14-9295-2014}
}
Abstract: The constraint of time-integrated zero area on the laser field is a fundamental requirement, both theoretically and experimentally, in the control of molecular dynamics. By using techniques of local and optimal control theory, we show how to enforce this constraint in two benchmark control problems, namely, molecular orientation and photofragmentation. The origin and the physical implications for the dynamics of this zero-area control field are discussed. © 2014 American Physical Society.
BibTeX:
@article{Sugny2014,
  author = {Sugny, D. and Vranckx, S. and Ndong, M. and Vaeck, N. and Atabek, O. and Desouter-Lecomte, M.},
  title = {Control of molecular dynamics with zero-area fields: Application to molecular orientation and photofragmentation},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2014},
  volume = {90},
  article number = {053404},
  doi = {10.1103/PhysRevA.90.053404}
}
Abstract: In our previous paper [B. T. Sutcliffe and R. G. Woolley, J. Chem. Phys. 137, 22A544 (2012)] we argued that the Born-Oppenheimer approximation could not be based on an exact transformation of the molecular Schrödinger equation. In this Comment we suggest that the fundamental reason for the approximate nature of the Born-Oppenheimer model is the lack of a complete set of functions for the electronic space, and the need to describe the continuous spectrum using spectral projection. © 2014 AIP Publishing LLC.
BibTeX:
@article{Sutcliffe2014,
  author = {Sutcliffe, B.T. and Woolley, R.G.},
  title = {Comment on "on the quantum theory of molecules" [J. Chem. Phys. 137, 22A544 (2012)]},
  journal = {Journal of Chemical Physics},
  year = {2014},
  volume = {140},
  article number = {4861897},
  doi = {10.1063/1.4861897}
}
Abstract: Volcanoes release large amounts of halogen species such as HCl and HBr, which can be converted into reactive halogens by heterogeneous photochemical reactions that are currently not fully characterized. Here we report on the first satellite detection of volcanic chlorine dioxide (OClO). Measurements were performed using the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography instrument for the ash-laden plume emitted after the 2011 eruption of Puyehue-Cordõn Caulle in Chile. We also identified volcanic BrO using the Ozone Monitoring Instrument, as well as enhanced HCl in data of the Microwave Limb Sounder instrument. These observations suggest that OClO was formed in the plume by the ClO + BrO reaction in presence of a large excess of ClO. The present satellite data set could help better understand reactive halogen chemistry in volcanic plumes and its impact on atmospheric composition. ©2013. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Theys2014,
  author = {Theys, N. and De Smedt, I. and Van Roozendael, M. and Froidevaux, L. and Clarisse, L. and Hendrick, F.},
  title = {First satellite detection of volcanic OClO after the eruption of Puyehue-Cordõn Caulle},
  journal = {Geophysical Research Letters},
  year = {2014},
  volume = {41},
  pages = {667-672},
  doi = {10.1002/2013GL058416}
}
Abstract: Ammonia (NH3) emissions in the atmosphere have increased substantially over the past decades, largely because of intensive livestock production and use of fertilizers. As a short-lived species, NH3 is highly variable in the atmosphere and its concentration is generally small, except near local sources. While ground-based measurements are possible, they are challenging and sparse. Advanced infrared sounders in orbit have recently demonstrated their capability to measure NH3, offering a new tool to refine global and regional budgets. In this paper we describe an improved retrieval scheme of NH3 total columns from the measurements of the Infrared Atmospheric Sounding Interferometer (IASI). It exploits the hyperspectral character of this instrument by using an extended spectral range (800-1200 cm-1) where NH3 is optically active. This scheme consists of the calculation of a dimensionless spectral index from the IASI level1C radiances, which is subsequently converted to a total NH3 column using look-up tables built from forward radiative transfer model simulations. We show how to retrieve the NH3 total columns from IASI quasi-globally and twice daily above both land and sea without large computational resources and with an improved detection limit. The retrieval also includes error characterization of the retrieved columns. Five years of IASI measurements (1 November 2007 to 31 October 2012) have been processed to acquire the first global and multiple-year data set of NH3 total columns, which are evaluated and compared to similar products from other retrieval methods. Spatial distributions from the five years data set are provided and analyzed at global and regional scales. In particular, we show the ability of this method to identify smaller emission sources than those previously reported, as well as transport patterns over the ocean. The five-year time series is further examined in terms of seasonality and interannual variability (in particular as a function of fire activity) separately for the Northern and Southern Hemispheres. © Author(s) 2014.
BibTeX:
@article{VanDamme2014,
  author = {Van Damme, M. and Clarisse, L. and Heald, C.L. and Hurtmans, D. and Ngadi, Y. and Clerbaux, C. and Dolman, A.J. and Erisman, J.W. and Coheur, P.F.},
  title = {Global distributions, time series and error characterization of atmospheric ammonia (NH3) from IASI satellite observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2014},
  volume = {14},
  pages = {2905-2922},
  doi = {10.5194/acp-14-2905-2014}
}
Abstract: Monitoring ammonia (NH3) concentrations on a global to regional scale is a challenge. Due to the limited availability of reliable ground-based measurements, the determination of NH3 distributions generally relies on model calculations. Novel remotely sensed NH3burdens provide valuable insights to complement traditional assessments for clear-sky conditions. This paper presents a first quantitative comparison between Atmospheric Sounding Interferometer (IASI) satellite observations and LOTOS-EUROS model results over Europe and Western Russia. A methodology to account for the variable retrieval sensitivity of the measurements is described. Four years of data (2008-2011) highlight three main agricultural hot spot areas in Europe: the Po Valley, the continental part of Northwestern Europe, and the Ebro Valley. The spatial comparison reveals a good overall agreement of the NH3 distributions not only in these source regions but also over remote areas and over sea when transport is observed. On average, the measured columns exceed the modeled ones, except for a few cases. Large discrepancies over several industrial areas in Eastern Europe and Russia point to underestimated emissions in the underlying inventories. The temporal analysis over the three hot spot areas reveals that the seasonality is well captured by the model when the lower sensitivity of the satellite measurements in the colder months is taken into account. Comparison of the daily time series indicates possible misrepresentations of the timing and magnitude of the emissions. Finally, specific attention to biomass burning events shows that modeled plumes are less spread out than the observed ones. This is confirmed for the 2010 Russian fires with a comparison using in situ observations. ©2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{VanDamme2014a,
  author = {Van Damme, M. and Wichink Kruit, R.J. and Schaap, M. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Dammers, E. and Dolman, A.J. and Erisman, J.W.},
  title = {Evaluating 4 years of atmospheric ammonia (NH3) over Europe using IASI satellite observations and LOTOS-EUROS model results},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2014},
  volume = {119},
  pages = {9549-9566},
  doi = {10.1002/2014JD021911}
}
Abstract: Relying on high-resolution Fourier transform infrared (FTIR) spectra, the present work involved extensive measurements of individual line intensities and self-broadening coefficients for the ν7 band of 12C2H4. The measured self-broadening coefficients exhibit a dependence on both J and Ka. Compared to the corresponding information available in the latest edition of the HITRAN spectroscopic database, the measured line intensities were found to be higher by about 10% for high J lines in the P branch and lower by about 5% for high J lines of the R branch, varying between these two limits roughly linearly with the line positions. The impact of the presently measured line intensities on retrievals of atmospheric ethylene in the 949.0-952.0cm-1 microwindow was evaluated using a subset of ground-based high-resolution FTIR solar spectra recorded at the Jungfraujoch station. The use of HITRAN 2012 with line intensities modified to match the present measurements led to a systematic reduction of the measured total columns of ethylene by -4.1 ± 0.1 %. © 2014 Elsevier Ltd.
BibTeX:
@article{VanderAuwera2014,
  author = {Vander Auwera, J. and Fayt, A. and Tudorie, M. and Rotger, M. and Boudon, V. and Franco, B. and Mahieu, E.},
  title = {Self-broadening coefficients and improved line intensities for the ν7 band of ethylene near 10.5 μm, and impact on ethylene retrievals from Jungfraujoch solar spectra},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2014},
  volume = {148},
  pages = {177-185},
  doi = {10.1016/j.jqsrt.2014.07.003}
}
Abstract: Energy levels, hyperfine interaction constants, and Landé gJ-factors are reported for n=2 states in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations. Valence, core-valence, and core-core correlation effects are taken into account through single and double-excitations from multireference expansions to increasing sets of active orbitals. A systematic comparison of the calculated hyperfine interaction constants is made with values from the available literature. © 2014 Elsevier Inc.
BibTeX:
@article{Verdebout2014,
  author = {Verdebout, S. and Nazé, C. and Jönsson, P. and Rynkun, P. and Godefroid, M. and Gaigalas, G.},
  title = {Hyperfine structures and Landé gJ-factors for n=2 states in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations},
  journal = {Atomic Data and Nuclear Data Tables},
  year = {2014},
  volume = {100},
  pages = {1111-1155},
  doi = {10.1016/j.adt.2014.05.001}
}
Abstract: A new method for the synthesis of 15N-labeled chiral β-diamines from a common precursor, either optically pure amino acids or anti-β-amino alcohols, is reported. The two diastereomeric series of vicinal diamines are produced through the nucleophilic ring opening of activated chiral aziridines. 15N was introduced by means of [ 15N]-benzylamine, prepared from 15NH4Cl. The final compounds are highly valuable because [1H-15N] NMR is considered a powerful tool for studying the chemical properties of platinum-based complexes. © 2012 Published by Elsevier Ltd.
BibTeX:
@article{Berger2013,
  author = {Berger, G. and Gelbcke, M. and Cauët, E. and Luhmer, M. and Nève, J. and Dufrasne, F.},
  title = {Synthesis of 15N-labeled vicinal diamines through N-activated chiral aziridines: Tools for the NMR study of platinum-based anticancer compounds},
  journal = {Tetrahedron Letters},
  year = {2013},
  volume = {54},
  pages = {545-548},
  doi = {10.1016/j.tetlet.2012.11.079}
}
Abstract: Herein, we report on the structure and dynamics of the aqueous Ca 2+ system studied by using ab initio molecular dynamics (AIMD) simulations. Our detailed study revealed the formation of well-formed hydration shells with characteristics that were significantly different to those of bulk water. To facilitate a robust comparison with state-of-the-art X-ray absorption fine structure (XAFS) data, we employ a 1st principles MD-XAFS procedure and directly compare simulated and experimental XAFS spectra. A comparison of the data for the aqueous Ca2+ system with those of the recently reported Zn2+, Fe3+, and Al3+ species showed that many of their structural characteristics correlated well with charge density on the cation. Some very important exceptions were found, which indicated a strong sensitivity of the solvent structure towards the cation′s valence electronic structure. Average dipole moments for the 2nd shell of all cations were suppressed relative to bulk water. Like a duck to water: An investigation into the solvent structure and dynamics around the Ca2+ cation was validated by comparison with XAFS data. A comparison with ab initio molecular dynamics studies of aqueous Zn2+, Fe3+, and Al 3+ was used to discuss general trends in the ability of these solvated cations to form extended structures. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
BibTeX:
@article{Bogatko2013a,
  author = {Bogatko, S. and Cauët, E. and Bylaska, E. and Schenter, G. and Fulton, J. and Weare, J.},
  title = {The aqueous Ca2+ system, in comparison with Zn2+, Fe3 +, and Al3 +: An ab initio molecular dynamics study},
  journal = {Chemistry - A European Journal},
  year = {2013},
  volume = {19},
  pages = {3047-3060},
  doi = {10.1002/chem.201202821}
}
Abstract: We present results showing that our recently developed density functional theory (DFT)-based speciation model of the aqueous Al3+ system has the potential to improve the interpretations of ESI-MS studies of aqueous metal cation hydrolytic speciation. The main advantages of our method are that (1) it allows for the calculation of the relative abundance of a given species which may be directly assigned to the signal intensity in a mass spectrum; (2) in cases where species with identical m/z ratios may coexist, the assignment can be unambiguously assigned based on their theoretical relative abundances. As a demonstration of its application, we study four pairs of monomer and dimer aqueous Al3+ species, each with identical m/z ratio. For some of these pairs our method predicts that the dominant species changes from the monomer to the dimer species under varying pH conditions. [Figure not available: see fulltext.] © 2013 American Society for Mass Spectrometry.
BibTeX:
@article{Bogatko2013b,
  author = {Bogatko, S. and Cauët, E. and Geerlings, P.},
  title = {Improved DFT-based interpretation of ESI-MS of aqueous metal cations},
  journal = {Journal of the American Society for Mass Spectrometry},
  year = {2013},
  volume = {24},
  pages = {926-931},
  doi = {10.1007/s13361-013-0617-x}
}
Abstract: We predict that electron attachment may be used with ESI-MS techniques to observe neutral Al metal aqua-oxo-hydroxo species and the complex polymerization and precipitation reactions in which they participate. Neutral aqueous metal species have, so far, been invisible to ESI-MS techniques. This journal is © 2013 the Owner Societies.
BibTeX:
@article{Bogatko2013,
  author = {Bogatko, S. and Cauët, E. and Geerlings, P.},
  title = {Rydberg electron capture by neutral Al hydrolysis products},
  journal = {Physical Chemistry Chemical Physics},
  year = {2013},
  volume = {15},
  pages = {15309-15311},
  doi = {10.1039/c3cp51935j}
}
Abstract: Depending on the magnitude of their eruptions, volcanoes impact the atmosphere at various temporal and spatial scales. The volcanic source remains a major unknown to rigorously assess these impacts. At the scale of an eruption, the limited knowledge of source parameters, including time variations of erupted mass flux and emission profile, currently represents the greatest issue that limits the reliability of volcanic cloud forecasts. Today, a growing number of satellite and remote sensing observations of distant plumes are becoming available, bringing indirect information on these source terms. Here, we develop an inverse modelling approach combining satellite observations of the volcanic plume with an Eulerian regional chemistry-transport model (CHIMERE) to characterise the volcanic SO2 emissions during an eruptive crisis. The May 2010 eruption of Eyjafjallajökull is a perfect case study to apply this method as the volcano emitted substantial amounts of SO2 during more than a month. We take advantage of the SO2 column amounts provided by a vast set of IASI (Infrared Atmospheric Sounding Interferometer) satellite images to reconstruct retrospectively the time series of the mid-tropospheric SO2 flux emitted by the volcano with a temporal resolution of ∼2 h, spanning the period from 1 to 12 May 2010. We show that no a priori knowledge on the SO2 flux is required for this reconstruction. The initialisation of chemistry-transport modelling with this reconstructed source allows for reliable simulation of the evolution of the long-lived tropospheric SO2 cloud over thousands of kilometres. Heterogeneities within the plume, which mainly result from the temporal variability of the emissions, are correctly tracked over a timescale of a week. The robustness of our approach is also demonstrated by the broad similarities between the SO2 flux history determined by this study and the ash discharge behaviour estimated by other means during the phases of high explosive activity at Eyjafjallajö kull in May 2010. Finally, we show how a sequential IASI data assimilation allows for a substantial improvement in the forecasts of the location and concentration of the plume compared to an approach assuming constant flux at the source. As the SO2 flux is an important indicator of the volcanic activity, this approach is also of interest to monitor poorly instrumented volcanoes from space. © Author(s) 2013.
BibTeX:
@article{Boichu2013,
  author = {Boichu, M. and Menut, L. and Khvorostyanov, D. and Clarisse, L. and Clerbaux, C. and Turquety, S.},
  title = {Inverting for volcanic SO2 flux at high temporal resolution using spaceborne plume imagery and chemistry-transport modelling: the 2010 Eyjafjallajökull eruption case study},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {8569-8584},
  doi = {10.5194/acp-13-8569-2013}
}
Abstract: Today, the electron affinity is experimentally well known for most of the elements and is a useful guideline for developing ab initio computational methods. However, the measurements of isotope shifts on the electron affinity are limited by both resolution and sensitivity. In this context, theory is of great help to further our knowledge and understanding of atomic structures, even though correlation plays a dominant role in negative ions' properties and, particularly, in the calculation of the specific mass shift contribution. This study solves the longstanding discrepancy between calculated and measured specific mass shifts on the electron affinity of chlorine (Berzinsh et al 1995 Phys. Rev. A 51 231). © 2013 IOP Publishing Ltd.
BibTeX:
@article{Carette2013,
  author = {Carette, T. and Godefroid, M.R.},
  title = {Isotope shift on the chlorine electron affinity revisited by an MCHF/CI approach},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2013},
  volume = {46},
  article number = {095003},
  doi = {10.1088/0953-4075/46/9/095003}
}
Abstract: The hyperfine interaction constants of the 2p4(3P)3p 2D3/2,5/2o, 4D1/2-7/2o, and 4P1/2-5/2o levels in neutral fluorine are investigated theoretically. Large-scale calculations are carried out using the multiconfiguration Hartree-Fock (MCHF) and Dirac-Hartree-Fock (MCDHF) methods. In the framework of the MCHF approach, the relativistic effects are taken into account in the Breit-Pauli approximation using nonrelativistic orbitals. In the fully relativistic approach, the orbitals are optimized using the Dirac-Coulomb Hamiltonian with correlation models inspired by the nonrelativistic calculations. Higher-order excitations are captured through multireference configuration interaction calculations including the Breit interaction. In a third (intermediate) approach, the Dirac-Coulomb-Breit Hamiltonian matrix is diagonalized in a relativistic configuration space built with nonrelativistic MCHF radial functions converted into Dirac spinors using the Pauli approximation. The magnetic dipole hyperfine-structure constants calculated with the three relativistic models are consistent and reveal unexpectedly large effects of relativity for 2D5/2o, 4P3/2o, and 4P5/2o. The agreement with the few available experimental values is satisfactory. The strong J dependence of relativistic corrections on the hyperfine constants is investigated through the detailed analysis of the orbital, spin-dipole, and contact relative contributions calculated with the nonrelativistic magnetic dipole operator. © 2013 American Physical Society.
BibTeX:
@article{Carette2013a,
  author = {Carette, T. and Nemouchi, M. and Li, J. and Godefroid, M.},
  title = {Relativistic effects on the hyperfine structures of 2p4(3P) 3p2Do,4Do, and 4Po in 19F i},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2013},
  volume = {88},
  article number = {042501},
  doi = {10.1103/PhysRevA.88.042501}
}
Abstract: In a previous article a dipole moment surface (DMS) of full-electron, multi-reference configuration interaction (MRCI) quality was obtained and used to calculate the rotational spectrum of methane vibrational ground state, by means of a combination of the mean field configuration interaction method (VMFCI) with a generalized perturbation theory. The theoretical line intensities were matching the experimental ones obtained at the SOLEIL synchrotron well within experimental uncertainties. However, not all third order terms were included in this DMS. In the present work, additional DMS points have been calculated and fitted using a complete third order expansion. The new results give R-branch intensities systematically smaller by about 1% compared to those previously obtained by using the same ab initio method, so still within experimental errors. The relevance of this DMS to calculate intensities for excited vibrational states, in particular for the dyad, is addressed. © 2013 Elsevier Inc. All rights reserved.
BibTeX:
@article{Cassam-Chenai2013,
  author = {Cassam-Chenaï, P. and Liévin, J.},
  title = {An improved third order dipole moment surface for methane},
  journal = {Journal of Molecular Spectroscopy},
  year = {2013},
  volume = {291},
  pages = {77-84},
  doi = {10.1016/j.jms.2013.07.004}
}
Abstract: Low energy electron-attachment-induced damage in DNA, where dissociation channels may involve multiple bonds including complex bond rearrangements and significant nuclear motions, is analyzed here. Quantum mechanics/molecular mechanics (QM/MM) calculations reveal how rearrangements of electron density after vertical electron attachment modulate the position and dynamics of the atomic nuclei in DNA. The nuclear motions involve the elongation of the P-O (P-O3′ and P-O5′) and C-C (C3′-C4′ and C4′-C5′) bonds for which the acquired kinetic energy becomes high enough so that the neighboring C3′-O3′ or C5′-O5′ phosphodiester bond may break almost immediately. Such dynamic behavior should happen on a very short time scale, within 15-30 fs, which is of the same order of magnitude as the time scale predicted for the excess electron to localize around the nucleobases. This result indicates that the C-O phosphodiester bonds can break before electron transfer from the backbone to the base. © 2013 American Chemical Society.
BibTeX:
@article{Cauet2013,
  author = {Cauët, E. and Bogatko, S. and Liévin, J. and De Proft, F. and Geerlings, P.},
  title = {Electron-attachment-induced DNA damage: Instantaneous strand breaks},
  journal = {Journal of Physical Chemistry B},
  year = {2013},
  volume = {117},
  pages = {9669-9676},
  doi = {10.1021/jp406320g}
}
Abstract: Atmospheric aerosols impact air quality and global climate. Space based measurements are the best way to observe their spatial and temporal distributions, and can also be used to gain better understanding of their chemical, physical and optical properties. Aerosol composition is the key parameter affecting the refractive index, which determines how much radiation is scattered and absorbed. Composition of aerosols is unfortunately not measured by state of the art satellite remote sounders. Here we use high resolution infrared measurements for aerosol type differentiation, exploiting, in that part of spectrum, the dependency of their refractive index on wavelength. We review existing detection methods and present a unified detection method based on linear discrimination analysis. We demonstrate this method on measurements of the Infrared Atmospheric Sounding Interferometer (IASI) and five different aerosol types, namely volcanic ash, windblown sand, sulfuric acid droplets, ammonium sulfate and smoke particles. We compare these with traditional MODIS AOD measurements. The detection of the last three types is unprecedented in the infrared in nadir mode, but is very promising, especially for sulfuric acid droplets which are detected in the lower troposphere and up to 6 months after injection in the upper troposphere/lower stratosphere. © 2013 Author(s).
BibTeX:
@article{Clarisse2013,
  author = {Clarisse, L. and Coheur, P.-F. and Prata, F. and Hadji-Lazaro, J. and Hurtmans, D. and Clerbaux, C.},
  title = {A unified approach to infrared aerosol remote sensing and type specification},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {2195-2221},
  doi = {10.5194/acp-13-2195-2013}
}
BibTeX:
@article{Clerbaux2013,
  author = {Clerbaux, C. and Crevoisier, C.},
  title = {New Directions: Infrared remote sensing of the troposphere from satellite: Less, but better},
  journal = {Atmospheric Environment},
  year = {2013},
  volume = {72},
  pages = {24-26},
  doi = {10.1016/j.atmosenv.2013.01.057}
}
Abstract: Three rovibrational bands of Ar-D2O and two rovibrational bands of Ar-HDO were observed in the 1.5 μm range by continuous wave cavity ringdown spectroscopy. Their analyses led to the determination of rotational constants for the upper states and vibrational shifts indicating that the potential energy surface is only slightly affected by the vibrational excitation. Some Coriolis couplings were identified. The observed lines were fitted to retrieve a 3.5 ns lifetime of the upper state, showing that even with a triple or double excitation quanta in the water subunit, the Ar-D2O and Ar-HDO complexes are long-lived species. © 2013 American Institute of Physics.
BibTeX:
@article{Didriche2013,
  author = {Didriche, K. and Földes, T.},
  title = {High resolution spectroscopy of the Ar-D2O and Ar-HDO molecular complexes in the near-infrared range},
  journal = {Journal of Chemical Physics},
  year = {2013},
  volume = {138},
  article number = {104307},
  doi = {10.1063/1.4794161}
}
Abstract: A high-resolution spectrum of the acetylene-water complex has been recorded in the overtone range. Two bands of C2H2-D2O were analysed, corresponding to the overtone excitations of either the acetylene or the water units. The vibrational shifts and the upper states rotational constants were retrieved, demonstrating that the geometry of the complex is only slightly modified by the excitation. A larger linewidth was observed for the 2CH band than for the 2OD + DOD band, probably due to the direct coupling of the 2CH excitation with the dissociation coordinate. © 2013 Copyright Taylor and Francis Group, LLC.
BibTeX:
@article{Didriche2013b,
  author = {Didriche, K. and Földes, T.},
  title = {High-resolution overtone spectra of molecular complexes},
  journal = {Molecular Physics},
  year = {2013},
  volume = {111},
  pages = {355-364},
  doi = {10.1080/00268976.2012.752880}
}
Abstract: The Π (11) ← Σ (00) 2NH (ν1+ν3) band of the NH3-Ar van der Waals complex formed in a supersonic jet expansion, with origin at 6628 cm -1 was recorded at high-resolution using cavity ring down spectroscopy. The analysis leads to upper state rotational constants and J-dependent predissociation lifetimes estimated from linewidth analysis, with a mean value about 0.6 ns. © 2013 AIP Publishing LLC.
BibTeX:
@article{Didriche2013a,
  author = {Didriche, K. and Földes, T. and Vanfleteren, T. and Herman, M.},
  title = {Communication: Overtone (2NH) spectroscopy of NH3-Ar},
  journal = {Journal of Chemical Physics},
  year = {2013},
  volume = {138},
  article number = {181101},
  doi = {10.1063/1.4804421}
}
Abstract: Hydrogen cyanide (HCN) and acetylene (C2H2) are ubiquitous atmospheric trace gases with medium lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. Because of their weak infrared absorption, overlapped by the CO2 Q branch near 720 cm-1, nadir sounders have up to now failed to measure these gases routinely. Taking into account CO 2 line mixing, we provide for the first time extensive measurements of HCN and C2H2 total columns at Reunion Island (21° S, 55° E) and Jungfraujoch (46° N, 8° E) in 2009-2010 using observations from the Infrared Atmospheric Sounding Interferometer (IASI). A first order comparison with local ground-based Fourier transform infraRed (FTIR) measurements has been carried out allowing tests of seasonal consistency which is reasonably captured, except for HCN at Jungfraujoch. The IASI data shows a greater tendency to high C2H2 values. We also examine a nonspecific biomass burning plume over austral Africa and show that the emission ratios with respect to CO agree with previously reported values. © Author(s) 2013.
BibTeX:
@article{Duflot2013,
  author = {Duflot, V. and Hurtmans, D. and Clarisse, L. and R'honi, Y. and Vigouroux, C. and De Mazière, M. and Mahieu, E. and Servais, C. and Clerbaux, C. and Coheur, P.-F.},
  title = {Measurements of hydrogen cyanide (HCN) and acetylene (C2H 2) from the Infrared Atmospheric Sounding Interferometer (IASI)},
  journal = {Atmospheric Measurement Techniques},
  year = {2013},
  volume = {6},
  pages = {917-925},
  doi = {10.5194/amt-6-917-2013}
}
Abstract: A very simple circuit for pseudo-tracking of the piezo actuator for continuous-wave cavity ring-down spectroscopy (cw-CRDS) is presented. The circuit is based on an ordinary positive-edge trigger D-type flip flop integrated circuit, has a low parts count, and can be easily assembled using only off the shelf components. The circuit can be straightforwardly incorporated into most cw-CRDS setups and, thanks to the increased ring-down event rate, higher sensitivity or lower data acquisition time can be achieved. © 2013 American Institute of Physics.
BibTeX:
@article{Foeldes2013,
  author = {Földes, T.},
  title = {Note: A very simple circuit for piezo actuator pseudo-tracking for continuous-wave cavity ring-down spectroscopy},
  journal = {Review of Scientific Instruments},
  year = {2013},
  volume = {84},
  article number = {016102},
  doi = {10.1063/1.4774044}
}
Abstract: No lines have been observed for transitions between the doublet and quartet levels of B i. Consequently, energy levels based on observation for the latter are obtained through extrapolation of wavelengths along the isoelectronic sequence for the 2s22p 2P3/2o - 2s2p2 4P5/2 transition. In this paper, accurate theoretical excitation energies from a partitioned-correlation- function-interaction (PCFI) method are reported for B i that include both relativistic effects in the Breit-Pauli approximation and a finite mass correction. Results are compared with extrapolated values from observed data. For B i our estimate of the excitation energy 28 959 ± 5 cm-1 is in better agreement with the values obtained by Edlén (1969) than those reported by Kramida and Ryabtsev (2007). Our method is validated by applying the same procedure to the separation of these levels in C ii. © 2013 American Physical Society.
BibTeX:
@article{FroeseFischer2013,
  author = {Froese Fischer, C. and Verdebout, S. and Godefroid, M. and Rynkun, P. and Jönsson, P. and Gaigalas, G.},
  title = {Doublet-quartet energy separation in boron: A partitioned-correlation- function-interaction method},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2013},
  volume = {88},
  article number = {062506},
  doi = {10.1103/PhysRevA.88.062506}
}
Abstract: Validation of ozone profiles measured from a nadir looking satellite instrument over Antarctica is a challenging task due to differences in their vertical sensitivity with ozonesonde measurements. In this paper, ozone observations provided by the Infrared Atmospheric Sounding Interferometer (IASI) instrument onboard the polar-orbiting satellite MetOp are compared with ozone profiles collected between August and October 2010 at McMurdo Station, Antarctica, during the Concordiasi measurement campaign. The main objective of the campaign was the satellite data validation. With this aim 20 zero-pressure sounding balloons carrying ozonesondes were launched during this period when the MetOp satellite was passing above McMurdo. This makes the dataset relevant for comparison, especially because the balloons covered the entire altitude range of IASI profiles. The validation methodology and the collocation criteria vary according to the availability of global positioning system auxiliary data with each electro-chemical cell ozonesonde observation. The relative mean difference is shown to depend on the vertical range investigated. The analysis shows a good agreement in the troposphere (below 10 km) and middle stratosphere (25-40 km), where the differences are lower than 10%. However a significant positive bias of about 10-26% is estimated in the lower stratosphere at 10-25 km, depending on altitude. The positive bias in the 10-25 km range is consistent with previously reported studies comparing in situ data with thermal infrared satellite measurements. This study allows for a better characterization of IASI-retrieved ozone over the polar region during ozone depletion/recovery processes. © Author(s) 2013.
BibTeX:
@article{Gazeaux2013,
  author = {Gazeaux, J. and Clerbaux, C. and George, M. and Hadji-Lazaro, J. and Kuttippurath, J. and Coheur, P.-F. and Hurtmans, D. and Deshler, T. and Kovilakam, M. and Campbell, P. and Guidard, V. and Rabier, F. and Thépaut, J.-N.},
  title = {Intercomparison of polar ozone profiles by IASI/MetOp sounder with 2010 Concordiasi ozonesonde observations},
  journal = {Atmospheric Measurement Techniques},
  year = {2013},
  volume = {6},
  pages = {613-620},
  doi = {10.5194/amt-6-613-2013}
}
Abstract: Near-infrared absorption spectra of a carbon dioxide sample enriched with oxygen-17 were recorded in the spectral range 1.2-1.25 νm. A high-resolution continuous scan Fourier transform interferometer fitted with a femto OPO/Idler laser source and cavity-enhanced absorption was used. The optimal root mean squared noise equivalent absorption was 1.2 × 10-10 cm -1Hz-1/2 per spectral element, corresponding to αmin = 10-8 cm-1. Two cold bands in 17O12C18O and one hot band in 16O12C17O were newly identified and rotationally analyzed. More lines than previously published (Lyulin et al. J. Quant. Spectrosc. Radiat. Transfer, 113, 2167 (2012)), were assigned in the observed bands of 12C17O2 and 16O12C17O. New upper state rotational constants were obtained from a band-by-band analysis. © 2013 Published by NRC Research Press.
BibTeX:
@article{Golebiowski2013,
  author = {Golebiowski, D. and Herman, M. and Lyulin, O.},
  title = {16O12C17O and 18O 12C17O spectroscopy in the 1.2-1.25 νm region},
  journal = {Canadian Journal of Physics},
  year = {2013},
  volume = {91},
  pages = {963-965},
  doi = {10.1139/cjp-2012-0482}
}
Abstract: We present the results of total column measurements of CO, C2H6 and fine-mode aerosol optical depth (AOD) during the "Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites" (BORTAS-B) campaign over eastern Canada. Ground-based observations, using Fourier transform spectrometers (FTSs) and sun photometers, were carried out in July and August 2011. These measurements were taken in Halifax, Nova Scotia, which is an ideal location to monitor the outflow of boreal fires from North America, and also in Toronto, Ontario. Measurements of fine-mode AOD enhancements were highly correlated with enhancements in coincident trace gas (CO and C2H6) observations between 19 and 21 July 2011, which is typical for a smoke plume event. In this paper, we focus on the identification of the origin and the transport of this smoke plume. We use back trajectories calculated by the Canadian Meteorological Centre as well as FLEXPART forward trajectories to demonstrate that the enhanced CO, C2H6 and fine-mode AOD seen near Halifax and Toronto originated from forest fires in northwestern Ontario that occurred between 17 and 19 July 2011. In addition, total column measurements of CO from the satellite-borne Infrared Atmospheric Sounding Interferometer (IASI) have been used to trace the smoke plume and to confirm the origin of the CO enhancement. Furthermore, the enhancement ratio-that is, in this case equivalent to the emission ratio (ERC2H6/CO)-was estimated from these ground-based observations. These C2H6 emission results from boreal fires in northwestern Ontario agree well with C2H6 emission measurements from other boreal regions, and are relatively high compared to fires from other geographical regions. The ground-based CO and C2H6 observations were compared with outputs from the 3-D global chemical transport model GEOS-Chem, using the Fire Locating And Modeling of Burning Emissions (FLAMBE) inventory. Agreement within the stated measurement uncertainty (∼3% for CO and ∼8% for C2H6) was found for the magnitude of the enhancement of the CO and C2H6 total columns between the measured and modelled results. However, there is a small shift in time (of approximately 6 h) of arrival of the plume over Halifax between the results. © Author(s) 2013.
BibTeX:
@article{Griffin2013,
  author = {Griffin, D. and Walker, K.A. and Franklin, J.E. and Parrington, M. and Whaley, C. and Hopper, J. and Drummond, J.R. and Palmer, P.I. and Strong, K. and Duck, T.J. and Abboud, I. and Bernath, P.F. and Clerbaux, C. and Coheur, P.-F. and Curry, K.R. and Dan, L. and Hyer, E. and Kliever, J. and Lesins, G. and Maurice, M. and Saha, A. and Tereszchuk, K. and Weaver, D.},
  title = {Investigation of CO, C2H6 and aerosols in a boreal fire plume over eastern Canada during BORTAS 2011 using ground-and satellite-based observations and model simulations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {10227-10241},
  doi = {10.5194/acp-13-10227-2013}
}
Abstract: The efficiency and insight of global, polyad-based modeling in overtone spectroscopy and dynamics is demonstrated. Both vibration and vibration-rotation polyads are considered. The spectroscopic implications of polyad Hamiltonians derive from their ability to account for the detailed line positions and intensities of spectral features and their unique predictive power. The dynamical implications of polyad Hamiltonians include classical bifurcations that lead to the birth of new vibrational modes and intramolecular vibrational-rotational energy redistribution over multiple timescales. The literature is reviewed, with emphasis on acetylene results. © 2013 the Owner Societies.
BibTeX:
@article{Herman2013,
  author = {Herman, M. and Perry, D.S.},
  title = {Molecular spectroscopy and dynamics: A polyad-based perspective},
  journal = {Physical Chemistry Chemical Physics},
  year = {2013},
  volume = {15},
  pages = {9970-9993},
  doi = {10.1039/c3cp50463h}
}
Abstract: An eight-year long reanalysis of atmospheric composition data covering the period 2003-2010 was constructed as part of the FP7-funded Monitoring Atmospheric Composition and Climate project by assimilating satellite data into a global model and data assimilation system. This reanalysis provides fields of chemically reactive gases, namely carbon monoxide, ozone, nitrogen oxides, and formaldehyde, as well as aerosols and greenhouse gases globally at a horizontal resolution of about 80 km for both the troposphere and the stratosphere. This paper describes the assimilation system for the reactive gases and presents validation results for the reactive gas analysis fields to document the data set and to give a first indication of its quality. Tropospheric CO values from the MACC reanalysis are on average 10-20% lower than routine observations from commercial aircrafts over airports through most of the troposphere, and have larger negative biases in the boundary layer at urban sites affected by air pollution, possibly due to an underestimation of CO or precursor emissions. Stratospheric ozone fields from the MACC reanalysis agree with ozonesondes and ACE-FTS data to within ±10% in most seasons and regions. In the troposphere the reanalysis shows biases of -5% to +10% with respect to ozonesondes and aircraft data in the extratropics, but has larger negative biases in the tropics. Area-averaged total column ozone agrees with ozone fields from a multi-sensor reanalysis data set to within a few percent. NO2 fields from the reanalysis show the right seasonality over polluted urban areas of the NH and over tropical biomass burning areas, but underestimate wintertime NO2 maxima over anthropogenic pollution regions and overestimate NO2 in northern and southern Africa during the tropical biomass burning seasons. Tropospheric HCHO is well simulated in the MACC reanalysis even though no satellite data are assimilated. It shows good agreement with independent SCIAMACHY retrievals over regions dominated by biogenic emissions with some anthropogenic input, such as the eastern US and China, and also over African regions influenced by biogenic sources and biomass burning. © Author(s) 2013.
BibTeX:
@article{Inness2013,
  author = {Inness, A. and Baier, F. and Benedetti, A. and Bouarar, I. and Chabrillat, S. and Clark, H. and Clerbaux, C. and Coheur, P. and Engelen, R.J. and Errera, Q. and Flemming, J. and George, M. and Granier, C. and Hadji-Lazaro, J. and Huijnen, V. and Hurtmans, D. and Jones, L. and Kaiser, J.W. and Kapsomenakis, J. and Lefever, K. and Leitão, J. and Razinger, M. and Richter, A. and Schultz, M.G. and Simmons, A.J. and Suttie, M. and Stein, O. and Thépaut, J.-N. and Thouret, V. and Vrekoussis, M. and Zerefos, C.},
  title = {The MACC reanalysis: An 8 yr data set of atmospheric composition},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {4073-4109},
  doi = {10.5194/acp-13-4073-2013}
}
Abstract: Aerosols from the Sarychev volcano eruption (Kuril Islands, northeast of Japan) were observed in the Arctic lower stratosphere a few days after the strongest SO2 injection which occurred on 15 and 16 June 2009. From the observations provided by the Infrared Atmospheric Sounding Interferometer (IASI) an estimated 0.9 Tg of sulphur dioxide was injected into the upper troposphere and lower stratosphere (UTLS). The resultant stratospheric sulphate aerosols were detected from satellites by the Optical Spectrograph and Infrared Imaging System (OSIRIS) limb sounder and by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and from the surface by the Network for the Detection of Atmospheric Composition Changes (NDACC) lidar deployed at OHP (Observatoire de Haute-Provence, France). By the first week of July the aerosol plume had spread out over the entire Arctic region. The Sarychev-induced stratospheric aerosol over the Kiruna region (north of Sweden) was measured by the Stratospheric and Tropospheric Aerosol Counter (STAC) during eight balloon flights planned in August and September 2009. During this balloon campaign the Micro Radiomètre Ballon (MicroRADIBAL) and the Spectroscopie d'Absorption Lunaire pour l'Observation des Minoritaires Ozone et NOx (SALOMON) remote-sensing instruments also observed these aerosols. Aerosol concentrations returned to near-background levels by spring 2010. The effective radius, the surface area density (SAD), the aerosol extinction, and the total sulphur mass from STAC in situ measurements are enhanced with mean values in the range 0.15-0.21 μm, 5.5-14.7 μm2 cm-3, 5.5-29.5 × 10-4 km-1, and 4.9-12.6 × 10-10 kg[S] kg-1[air], respectively, between 14 km and 18 km. The observed and modelled e-folding time of sulphate aerosols from the Sarychev eruption is around 70-80 days, a value much shorter than the 12-14 months calculated for aerosols from the 1991 eruption of Mt Pinatubo. The OSIRIS stratospheric aerosol optical depth (AOD) at 750 nm is enhanced by a factor of 6, with a value of 0.02 in late July compared to 0.0035 before the eruption. The HadGEM2 and MIMOSA model outputs indicate that aerosol layers in polar region up to 14-15 km are largely modulated by stratosphere-troposphere exchange processes. The spatial extent of the Sarychev plume is well represented in the HadGEM2 model with lower altitudes of the plume being controlled by upper tropospheric troughs which displace the plume downward and upper altitudes around 18-20 km, in agreement with lidar observations. Good consistency is found between the HadGEM2 sulphur mass density and the value inferred from the STAC observations, with a maximum located about 1 km above the tropopause ranging from 1 to 2 × 10 -9 kg[S] kg-1[air], which is one order of magnitude higher than the background level. © Author(s) 2013.
BibTeX:
@article{Jegou2013,
  author = {Jégou, F. and Berthet, G. and Brogniez, C. and Renard, J.-B. and François, P. and Haywood, J.M. and Jones, A. and Bourgeois, Q. and Lurton, T. and Auriol, F. and Godin-Beekmann, S. and Guimbaud, C. and Krysztofiak, G. and Gaubicher, B. and Chartier, M. and Clarisse, L. and Clerbaux, C. and Balois, J.Y. and Verwaerde, C. and Daugeron, D.},
  title = {Stratospheric aerosols from the Sarychev volcano eruption in the 2009 Arctic summer},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {6533-6552},
  doi = {10.5194/acp-13-6533-2013}
}
Abstract: Relativistic configuration interaction (RCI) calculations are performed for 291 states belonging to the configurations 1s22s22p, 1s22s2p2, 1s22p3, 1s 22s23l, 1s22s2p3l, 1s22p 23l, 1s22s24l′, 1s 22s2p4l′, and 1s22p24l′ (l = 0,1,2 and l′ = 0,1,2,3) in boron-like ions Si X and Ti XVIII to Cu XXV. Electron correlation effects are represented in the wave functions by large configuration state function (CSF) expansions. States are transformed from jj-coupling to LS-coupling, and the LS-percentage compositions are used for labeling the levels. Radiative electric dipole transition rates are given for all ions, leading to massive data sets. Calculated energy levels are compared with other theoretical predictions and crosschecked against the Chianti database, NIST recommended values, and other observations. The accuracy of the calculations are high enough to facilitate the identification of observed spectral lines. © 2013 ESO.
BibTeX:
@article{Joensson2013,
  author = {Jönsson, P. and Ekman, J. and Gustafsson, S. and Hartman, H. and Karlsson, L.B. and Du Rietz, R. and Gaigalas, G. and Godefroid, M.R. and Froese Fischer, C.},
  title = {Energy levels and transition rates for the boron isoelectronic sequence: Si X, Ti XVIII-Cu XXV},
  journal = {Astronomy and Astrophysics},
  year = {2013},
  volume = {559},
  article number = {A100},
  doi = {10.1051/0004-6361/201321893}
}
Abstract: The development of multiconfiguration computer packages for atomic structure calculations is reviewed with special attention to the work of Charlotte Froese Fischer. The underlying theory is described along with methodologies to choose basis expansions of configuration state functions. Calculations of energies and transitions rates are presented and the accuracy of the results is assessed. Limitations of multiconfiguration methods are discussed and it is shown how these limitations can be circumvented by a division of the original large-scale computational problem into a number of smaller problems. © 2013 AIP Publishing LLC.
BibTeX:
@conference{Joensson2013a,
  author = {Jönsson, P. and Godefroid, M. and Gaigalas, G. and Bieroń, J. and Brage, T.},
  title = {Accurate transition probabilities from large-scale multiconfiguration calculations - A tribute to Charlotte Froese Fischer},
  journal = {AIP Conference Proceedings},
  year = {2013},
  volume = {1545},
  pages = {266-278},
  doi = {10.1063/1.4815863}
}
Abstract: The fires around Moscow in July and August 2010 emitted a large amount of pollutants to the atmosphere. Here we estimate the carbon monoxide (CO) source strength of the Moscow fires in July and August by using the TM5-4DVAR system in combination with CO column observations of the Infrared Atmospheric Sounding Interferometer (IASI). It is shown that the IASI observations provide a strong constraint on the total emissions needed in the model. Irrespective of the prior emissions used, the optimised CO fire emission estimates from mid-July to mid-August 2010 amount to approximately 24TgCO. This estimate depends only weakly (< 15%) on the assumed diurnal variations and injection height of the emissions. However, the estimated emissions might depend on unaccounted model uncertainties such as vertical transport. Our emission estimate of 22-27 TgCO during roughly one month of intense burning is less than suggested by another recent study, but substantially larger than predicted by the bottom-up inventories. This latter discrepancy suggests that bottom-up emission estimates for extreme peat burning events require improvements. © Author(s) 2013.
BibTeX:
@article{Krol2013,
  author = {Krol, M. and Peters, W. and Hooghiemstra, P. and George, M. and Clerbaux, C. and Hurtmans, D. and McInerney, D. and Sedano, F. and Bergamaschi, P. and El Hajj, M. and Kaiser, J.W. and Fisher, D. and Yershov, V. and Muller, J.-P.},
  title = {How much CO was emitted by the 2010 fires around Moscow?},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {4737-4747},
  doi = {10.5194/acp-13-4737-2013}
}
Abstract: The high-resolution infrared spectra of the ν1 + ν3 (2CH) band of the Ar-C2H2 complex has been recorded from 6544 to 6566 cm-1. The previously reported K a = 1 ← 0, 2 ← 1, and 0 ← 1 subbands were observed and the Ka = 1 ← 2, 2 ← 3, and 3 ← 2 subbands were assigned for the first time. The intermolecular potential energy surface of this complex has been calculated ab initio and optimized by fitting the new high-resolution data. Refined intermolecular potential energy surfaces have been obtained for the ground vibrational state and for the excited v1 = v3 = 1 stretching state. For the former state, the results of the analysis are satisfactory and the microwave transitions of the complex are reproduced with a root-mean-square deviation of 5 MHz. For the latter state, systematic discrepancies arise in the analysis. © 2013 American Chemical Society.
BibTeX:
@article{Lauzin2013,
  author = {Lauzin, C. and Coudert, L.H. and Herman, M. and Liévin, J.},
  title = {Ab initio intermolecular potential of Ar-C2H2 refined using high-resolution spectroscopic data},
  journal = {Journal of Physical Chemistry A},
  year = {2013},
  volume = {117},
  pages = {13767-13774},
  doi = {10.1021/jp408013n}
}
Abstract: We calculate the index of refraction of sodium matter waves propagating through a gas of nitrogen molecules. We use a recent ab initio potential for the ground state of the NaN2 van der Waals complex to perform quantal close-coupling calculations and compute the index of refraction as a function of the projectile velocity. We obtain good agreement with the available experimental data. We show that the refractive index contains glory oscillations but that they are damped by the averaging over the thermal motion of the N 2 molecules. These oscillations appear at lower temperatures and projectile velocity. We also investigate the behavior of the refractive index at low temperature and low projectile velocity to show its dependence on the rotational state of N2 and discuss the advantage of using diatomic molecules as projectiles. © 2013 American Physical Society.
BibTeX:
@article{Loreau2013,
  author = {Loreau, J. and Kharchenko, V. and Dalgarno, A.},
  title = {Index of refraction of molecular nitrogen for sodium matter waves},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2013},
  volume = {87},
  article number = {012708},
  doi = {10.1103/PhysRevA.87.012708}
}
Abstract: We investigate the interaction of ground and excited states of a silver atom with noble gases (NG), including helium. Born-Oppenheimer potential energy curves are calculated with quantum chemistry methods and spin-orbit effects in the excited states are included by assuming a spin-orbit splitting independent of the internuclear distance. We compare our results with experimentally available spectroscopic data, as well as with previous calculations. Because of strong spin-orbit interactions, excited Ag-NG potential energy curves cannot be fitted to Morse-like potentials. We find that the labeling of the observed vibrational levels has to be shifted by one unit. © 2013 American Institute of Physics.
BibTeX:
@article{Loreau2013a,
  author = {Loreau, J. and Sadeghpour, H.R. and Dalgarno, A.},
  title = {Potential energy curves for the interaction of Ag(5s) and Ag(5p) with noble gas atoms},
  journal = {Journal of Chemical Physics},
  year = {2013},
  volume = {138},
  article number = {084301},
  doi = {10.1063/1.4790586}
}
Abstract: We investigate the photodissociation of HeH+ in the metastable triplet state as well as its formation through the inverse process, radiative association. In models of astrophysical plasmas, HeH+ is assumed to be present only in the ground state, and the influence of the triplet state has not been explored. It may be formed by radiative association during collisions between a proton and metastable helium, which are present in significant concentrations in nebulae. The triplet state can also be formed by association of He+ and H, although this process is less likely to occur. We compute the cross sections and rate coefficients corresponding to the photodissociation of the triplet state by UV photons from a central star using a wave packet method. We show that the photodissociation cross sections depend strongly on the initial vibrational state and that the effects of excited electronic states and nonadiabatic couplings cannot be neglected. We then calculate the cross section and rate coefficient for the radiative association of HeH+ in the metastable triplet state. © 2013 American Chemical Society.
BibTeX:
@article{Loreau2013b,
  author = {Loreau, J. and Vranckx, S. and Desouter-Lecomte, M. and Vaeck, N. and Dalgarno, A.},
  title = {Photodissociation and radiative association of HeH+ in the metastable triplet state},
  journal = {Journal of Physical Chemistry A},
  year = {2013},
  volume = {117},
  pages = {9486-9492},
  doi = {10.1021/jp312007q}
}
Abstract: An atomic spectral line is characteristic of the element producing the spectrum. The line also depends on the isotope. The program ris3 (Relativistic Isotope Shift) calculates the electron density at the origin and the normal and specific mass shift parameters. Combining these electronic quantities with available nuclear data, isotope-dependent energy level shifts are determined. © 2013 Elsevier B.V. All rights reserved.
BibTeX:
@article{Naze2013,
  author = {Nazé, C. and Gaidamauskas, E. and Gaigalas, G. and Godefroid, M. and Jönsson, P.},
  title = {Ris3: A program for relativistic isotope shift calculations},
  journal = {Computer Physics Communications},
  year = {2013},
  volume = {184},
  pages = {2187-2196},
  doi = {10.1016/j.cpc.2013.02.015}
}
Abstract: During the last decades, remote sensing sounders have demonstrated their capability for monitoring atmospheric composition and pollution. With now 5 years of continuous observations of IASI instrument, flying on board of MetOp-A platform, we are able to analyze long term variations of atmospheric molecules. This article involves new tendencies for CO and CO2 molecules based on IASI LIC radiances. Comparisons with total columns are also provided. © 2013 AIP Publishing LLC.
BibTeX:
@conference{Oudot2013,
  author = {Oudot, C. and Clerbaux, C. and Lazaro, J.H. and George, M. and Safieddine, S. and Clarisse, L. and Hurtmans, D. and Coheur, P.},
  title = {IASI/MetOp sounder contribution for atmospheric composition monitoring: 4-year study of radiance data},
  journal = {AIP Conference Proceedings},
  year = {2013},
  volume = {1531},
  pages = {212-215},
  doi = {10.1063/1.4804744}
}
Abstract: In July 2010, several hundred forest and peat fires broke out across central Russia during its hottest summer on record. Here, we analyze these wildfires using observations of the Infrared Atmospheric Sounding Interferometer (IASI). Carbon monoxide (CO), ammonia (NH3) and formic acid (HCOOH) total columns are presented for the year 2010. Maximum total columns were found to be one order (for CO and HCOOH) and two orders (for NH3) of magnitude larger than typical background values. The temporal evolution of NH3 and HCOOH enhancement ratios relative to CO are presented. Evidence of secondary formation of HCOOH is found, with enhancement ratios exceeding reported emission ratios in fresh plumes. We estimate the total emitted masses for the period July-August 2010 over the center of western Russia; they are 19-33 Tg (CO), 0.7-2.6 Tg (NH3) and 0.9-3.9 Tg (HCOOH). For NH3 and HCOOH, these quantities are comparable to what is emitted in the course of a whole year by all extratropical forest fires. © Author(s) 2013.
BibTeX:
@article{RHoni2013,
  author = {R'Honi, Y. and Clarisse, L. and Clerbaux, C. and Hurtmans, D. and Duflot, V. and Turquety, S. and Ngadi, Y. and Coheur, P.-F.},
  title = {Exceptional emissions of NH3 and HCOOH in the 2010 Russian wildfires},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {4171-4181},
  doi = {10.5194/acp-13-4171-2013}
}
Abstract: We present absorption bands of carbon dioxide isotopologues, detected by the Solar Occultation for the Infrared Range (SOIR) instrument on board the Venus Express Satellite. The SOIR instrument combines an echelle spectrometer and an Acousto-Optical Tunable Filter (AOTF) for order selection. It performs solar occultation measurements in the Venus atmosphere in the IR region (2.2-4.3μm), at a resolution of 0.12-0.18cm-1. The wavelength range probed by SOIR allows a detailed chemical inventory of the Venus atmosphere above the cloud layer (65-150km) to be made with emphasis on the vertical distributions of gases. Thanks to the SOIR spectral resolution, a new CO2 absorption band was identified: the 21101-01101 band of 16O12C18O with R branch up to J=31. Two other previously reported bands were observed dispelling any doubts about their identifications: the 20001-00001 band of 16O13C18O [Villanueva G, et al. J Quant Spectrosc Radiat Transfer 2008;109:883-894] and the 01111-00001 band of 16O12C18O [Villanueva G, et al. J Quant Spectrosc Radiat Transfer 2008;109:883-894 and Wilquet V, et al. J Quant Spectrosc Radiat Transfer 2008;109:895-905]. These bands were analyzed, and spectroscopic constants characterizing them were obtained. The rotational assignment of the 20001-00001 band was corrected. The present measurements are compared with data available in the HITRAN database. © 2012 Elsevier Ltd.
BibTeX:
@article{Robert2013,
  author = {Robert, S. and Borkov, Y.G. and Vander Auwera, J. and Drummond, R. and Mahieux, A. and Wilquet, V. and Vandaele, A.C. and Perevalov, V.I. and Tashkun, S.A. and Bertaux, J.L.},
  title = {Assignment and rotational analysis of new absorption bands of carbon dioxide isotopologues in Venus spectra},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2013},
  volume = {114},
  pages = {29-41},
  doi = {10.1016/j.jqsrt.2012.08.023}
}
Abstract: Tropospheric ozone (O3) columns in urban and rural regions as seen by the Infrared Atmospheric Sounding Interferometer (IASI) are analyzed along with the Global Ozone Monitoring Experiment (GOME-2) tropospheric nitrogen dioxide (NO2) columns. Results over nine cities of the Northern Hemisphere for the period 2008-2011 show a typical seasonal behavior of tropospheric O3, with a first maximum reached in late spring because of stratospheric intrusion mainly and a continuous rise till the summer because of the anthropogenic-based ozone production. Over the East Asian cities, a decrease in the O3 tropospheric column is detected during the monsoon period. Seasonal cycling of tropospheric NO2 shows consistent higher values during winter because of the higher anthropogenic sources and longer lifetime. In rural regions, a complex relation between the O3 and NO2 columns is found, with good correlation in summer and winter. O3 concentrations in rural sites are found to be comparable to those closest to the anthropogenic emission sources, with peak values in spring and summer. Furthermore, the effect of the reduction of pollutant emissions in the Beijing region during the Olympic Games of 2008 compared to the same summer period in the following 3 years is studied. GOME-2 NO2 measurements show a reduction up to 54% above Beijing during this period compared to the following 3 years. IASI O3 measurements show an increase of 12% during July 2008 followed by a decrease of 5-6% during the months of August and September. Key Points Study the seasonal variation of tropospheric ozone and nitrogen dioxideCompare between urban and rural tropospheric O3 and NO2Analyze the relationship between tropospheric NO2 and O3 in rural regions ©2013. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Safieddine2013,
  author = {Safieddine, S. and Clerbaux, C. and George, M. and Hadji-Lazaro, J. and Hurtmans, D. and Coheur, P.-F. and Wespes, C. and Loyola, D. and Valks, P. and Hao, N.},
  title = {Tropospheric ozone and nitrogen dioxide measurements in urban and rural regions as seen by IASI and GOME-2},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2013},
  volume = {118},
  pages = {10555-10566},
  doi = {10.1002/jgrd.50669}
}
Abstract: In view of preparing Cu polynuclear complexes with dipyrromethene ligands, the mononuclear complexes [Cu(ii)(dipy)2] (dipyH = 5-phenyldipyrromethene) and [Cu(ii)(dpdipy)2] (dpdipyH = 1,5,9-triphenyldipyrromethene) have been prepared and characterized by X-ray crystallography, mass spectrometry and EPR spectroscopy. Their peculiar redox and spectroscopic (absorption/emission) behaviours are discussed. In contrast to CuII complexes of 1,1′-bidypyrrin, the reduction electrolysis of [Cu(ii)(dpdipy)2] leads to decomposition products on a time scale of a few hours. Moreover in relation to this observation, [Cu(i)(dpdipy) 2]- could not be synthesized in spite of the Cu I core protection by the phenyl substituents in ortho position of the nitrogen atoms. Theoretical calculations provide some explanations for this instability. Interestingly [Cu(ii)(dipy)2] and [Cu(ii)(dpdipy) 2] display weak luminescence at room temperature, attributed to a ligand centered emission. © 2013 The Royal Society of Chemistry.
BibTeX:
@article{Servaty2013,
  author = {Servaty, K. and Cauët, E. and Thomas, F. and Lambermont, J. and Gerbaux, P. and De Winter, J. and Ovaere, M. and Volker, L. and Vaeck, N. and Van Meervelt, L. and Dehaen, W. and Moucheron, C. and Kirsch-De Mesmaeker, A.},
  title = {Peculiar properties of homoleptic Cu complexes with dipyrromethene derivatives},
  journal = {Dalton Transactions},
  year = {2013},
  volume = {42},
  pages = {14188-14199},
  doi = {10.1039/c3dt51541a}
}
Abstract: Sulfur concentrations have been measured in 28 melt inclusions (MIs) in plagioclase, clinopyroxene, and olivine crystals extracted from tephra produced during the explosive eruption of Grímsvötn in May 2011. The results are compared to sulfur concentrations in the groundmass glass in order to estimate the mass of sulfur brought to surface during the eruption. Satellite measurements yield order of magnitude lower sulfur ( 0.2 Tg) in the eruption plume than estimated from the difference between MI and the groundmass glass. This sulfur "deficit" is readily explained by sulfur adhering to tephra grains but principally by sulfide globules caused by basalt-sulfide melt exsolution before degassing. A mass balance calculation reveals that approximately  0.8 Tg of SO2 is present as globules, representing  50% of the total sulfur budget. Most of the sulfide globules likely reside at depth due to their elevated density, for potential later remobilization by new magma or hydrothermal circulation. Key Points H2S and SO2 degassing is estimated for the 2011 eruption of Grímsvötn Satellite-based SO2 mass loading is lower than from mineral melt inclusions Half of S resides as sulfide globules; 25% enter the stratosphere ©2013. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Sigmarsson2013,
  author = {Sigmarsson, O. and Haddadi, B. and Carn, S. and Moune, S. and Gudnason, J. and Yang, K. and Clarisse, L.},
  title = {The sulfur budget of the 2011 Grímsvötn eruption, Iceland},
  journal = {Geophysical Research Letters},
  year = {2013},
  volume = {40},
  pages = {6095-6100},
  doi = {10.1002/2013GL057760}
}
Abstract: Continuous carbon monoxide (CO) total column densities above the Universidad Nacional Autónoma de México (UNAM) campus in Mexico City have been derived from solar absorption infrared spectroscopic measurements since October 2007. Its diurnal evolution is used in the present study in conjunction with other ground-based and satellite data to develop a top-down emission estimate of the annual CO emission of the Mexico City Metropolitan Area (MCMA). The growth-rate of the total column around noon under low ventilation conditions is calculated and allows us to derive the average surface emission-flux at UNAM, while similar measurements taken at the edge of the MCMA in Tecámac provide information on background CO levels in the Mexico basin. Based on 3 yr of measurements, CO column measurements from the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument are used to reconstruct the spatial distribution of this anthropogenic pollutant over the MCMA. The agreement between the measured columns of the satellite and ground-based measurements is excellent, particularly when a comparison strategy based on time-displaced air masses is used. The annual emission of the Mexico Megacity is estimated to be (2.15 ± 0.5) Tg yr-1 for the year 2008, while the official inventory for that year reported 1.6 Tg yr -1. The difference is slightly higher than the conservative uncertainty estimated in this work suggesting that the emission might be underestimated by the conventional bottom-up method. A larger discrepancy is found in the spatial distribution of the emissions, when comparing the emission flux over UNAM (derived from the ground-based measurement) with that of the inventory integrated over a representative area. The methodology presented here represents a new and useful strategy to evaluate the contribution of megacities to the global anthropogenic gas emissions. Additionally, three different strategies to compare ground and space-based measurements above an inhomogeneous and strongly contaminated area like Mexico City are presented and discussed. © Author(s) 2013.
BibTeX:
@article{Stremme2013,
  author = {Stremme, W. and Grutter, M. and Rivera, C. and Bezanilla, A. and Garcia, A.R. and Ortega, I. and George, M. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Hannigan, J.W. and Coffey, M.T.},
  title = {Top-down estimation of carbon monoxide emissions from the Mexico Megacity based on FTIR measurements from ground and space},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {1357-1376},
  doi = {10.5194/acp-13-1357-2013}
}
Abstract: Existing descriptions of bi-directional ammonia (NH3) land-atmosphere exchange incorporate temperature and moisture controls, and are beginning to be used in regional chemical transport models. However, such models have typically applied simpler emission factors to upscale the main NH3 emission terms. While this approach has successfully simulated the main spatial patterns on local to global scales, it fails to address the environment- and climate- dependence of emissions. To handle these issues, we outline the basis for a new modelling paradigm where both NH3 emissions and deposition are calculated online according to diurnal, seasonal and spatial differences in meteorology. We show how measurements reveal a strong, but complex pattern of climatic dependence, which is increasingly being characterized using ground-based NH3 monitoring and satellite observations, while advances in process-based modelling are illustrated for agricultural and natural sources, including a global application for seabird colonies. A future architecture for NH3 emission-deposition modelling is proposed that integrates the spatio-temporal interactions, and provides the necessary © 2013 The Author(s) Published by the Royal Society. All rights reserved.
BibTeX:
@article{Sutton2013,
  author = {Sutton, M.A. and Reis, S. and Riddick, S.N. and Dragosits, U. and Nemitz, E. and Theobald, M.R. and Tang, Y.S. and Braban, C.F. and Vieno, M. and Dore, A.J. and Mitchell, R.F. and Wanless, S. and Daunt, F. and Fowler, D. and Blackall, T.D. and Milford, C. and Flechard, C.R. and Loubet, B. and Massad, R. and Cellier, P. and Personne, E. and Coheur, P.F. and Clarisse, L. and Van Damme, M. and Ngadi, Y. and Clerbaux, C. and Skjøth, C.A. and Geels, C. and Hertel, O. and Kruit, R.J.W. and Pinder, R.W. and Bash, J.O. and Walker, J.T. and Simpson, D. and Horváth, L. and Misselbrook, T.H. and Bleeker, A. and Dentener, F. and de Vries, W.},
  title = {Towards a climate-dependent paradigm of ammonia emission and deposition},
  journal = {Philosophical Transactions of the Royal Society B: Biological Sciences},
  year = {2013},
  volume = {368},
  doi = {10.1098/rstb.2013.0166}
}
Abstract: To further our understanding of the effects of biomass burning emissions on atmospheric composition, the BORTAS campaign (BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) was conducted on 12 July to 3 August 2011 during the boreal forest fire season in Canada. The simultaneous aerial, ground and satellite measurement campaign sought to record instances of boreal biomass burning to measure the tropo-spheric volume mixing ratios (VMRs) of short- and long-lived trace molecular species from biomass burning emissions. The goal was to investigate the connection between the composition and the distribution of these pyrogenic outflows and their resulting perturbation to atmospheric chemistry, with particular focus on oxidant species to determine the overall impact on the oxidizing capacity of the free troposphere. Measurements of pyrogenic trace species in boreal biomass burning plumes were made by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) onboard the Canadian Space Agency (CSA) SCISAT-1 satellite during the BORTAS campaign. Even though biomass burning emissions are typically confined to the boundary layer, outflows are often injected into the upper troposphere by isolated convection and fire-related convective processes, thus allowing space-borne instruments to measure these pyrogenic outflows. An extensive set of 14 molecules - CH 3OH, C2H2, C2H6, C 3H6O, CO, HCN, HCOOH, HNO3, H2CO, NO, NO2, OCS, O3, and PAN -have been analysed. Included in this analysis is the calculation of age-dependent sets of enhancement ratios for each of the species originating from fires in North America (Canada, Alaska) and Siberia for a period of up to 7 days. Ratio values for the shorter lived primary pyrogenic species decrease over time primarily due to oxidation by the OH radical as the plume ages and values for longer lived species such as HCN and C2H6 remain relatively unchanged. Increasing negative values are observed for the oxidant species, including O3, indicating a destruction process in the plume as it ages such that concentrations of the oxidant species have dropped below their off-plume values. Results from previous campaigns have indicated that values for the molar ratios of ΔO 3 / ΔCO obtained from the measurements of the pyrogenic outflow from boreal fires are highly variable and range from negative to positive, irrespective of plume age. This variability has been attributed to pollution effects where the pyrogenic outflows have mixed with either local urban NO x emissions or pyrogenic emissions from the long-range transport of older plumes, thus affecting the production of O3 within the plumes. The results from this study have identified another potential cause of the variability in O3 concentrations observed in the measurements of biomass burning emissions, where evidence of stratosphere-troposphere exchange due to the pyroconvective updrafts from fires has been identified. Perturbations caused by the lofted emissions in these fire-aided convective processes may result in the intrusion of stratospheric air masses into the free troposphere and subsequent mixing of stratospheric O3 into the pyrogenic outflows causing fluctuations in observed ΔO3/ΔCO molar ratios. © Author(s) 2013.
BibTeX:
@article{Tereszchuk2013,
  author = {Tereszchuk, K.A. and González Abad, G. and Clerbaux, C. and Hadji-Lazaro, J. and Hurtmans, D. and Coheur, P.-F. and Bernath, P.F.},
  title = {ACE-FTS observations of pyrogenic trace species in boreal biomass burning plumes during BORTAS},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {4529-4541},
  doi = {10.5194/acp-13-4529-2013}
}
Abstract: Sulphur dioxide (SO2) fluxes of active degassing volcanoes are routinely measured with ground-based equipment to characterize and monitor volcanic activity. SO2 of unmonitored volcanoes or from explosive volcanic eruptions, can be measured with satellites. However, remote-sensing methods based on absorption spectroscopy generally provide integrated amounts of already dispersed plumes of SO2 and satellite derived flux estimates are rarely reported. Here we review a number of different techniques to derive volcanic SO2 fluxes using satellite measurements of plumes of SO 2 and investigate the temporal evolution of the total emissions of SO2 for three very different volcanic events in 2011: Puyehue-Cordón Caulle (Chile), Nyamulagira (DR Congo) and Nabro (Eritrea). High spectral resolution satellite instruments operating both in the ultraviolet-visible (OMI/Aura and GOME-2/MetOp-A) and thermal infrared (IASI/MetOp-A) spectral ranges, and multispectral satellite instruments operating in the thermal infrared (MODIS/Terra-Aqua) are used. We show that satellite data can provide fluxes with a sampling of a day or less (few hours in the best case). Generally the flux results from the different methods are consistent, and we discuss the advantages and weaknesses of each technique. Although the primary objective of this study is the calculation of SO 2 fluxes, it also enables us to assess the consistency of the SO 2 products from the different sensors used. © 2013 Author(s).
BibTeX:
@article{Theys2013,
  author = {Theys, N. and Campion, R. and Clarisse, L. and Brenot, H. and Van Gent, J. and Dils, B. and Corradini, S. and Merucci, L. and Coheur, P.-F. and Van Roozendael, M. and Hurtmans, D. and Clerbaux, C. and Tait, S. and Ferrucci, F.},
  title = {Volcanic SO2 fluxes derived from satellite data: A survey using OMI, GOME-2, IASI and MODIS},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {5945-5968},
  doi = {10.5194/acp-13-5945-2013}
}
Abstract: We present a regional emission inventory constructed based on satellite observations of fire activity (MODIS) and the ORCHIDEE vegetation model, and its application to air quality forecasting. After a brief description of the variability of fire activity in the Euro-Mediterranean region during the past 8 years, a full evaluation of the emissions is performed for the case study of the summer of 2007, during the large Greek fires event. Therefore, regional simulations undertaken with the CHIMERE chemistry-transport model (CTM) are compared to surface and satellite observations of trace gases and aerosols. © Springer Science+Business Media Dordrecht 2014.
BibTeX:
@article{Turquety2013,
  author = {Turquety, S. and Messina, P. and Stromatas, S. and Anav, A. and Menut, L. and Bessagnet, B. and Péré, J.-C. and Drobinski, P. and Coheur, P.F. and Rhoni, Y. and Clerbaux, C. and Tanré, D.},
  title = {Impact of Fire Emissions on Air Quality in the Euro-Mediterranean Region},
  journal = {NATO Science for Peace and Security Series C: Environmental Security},
  year = {2013},
  volume = {137},
  pages = {363-367},
  doi = {10.1007/978-94-007-5577-2_61}
}
Abstract: Transmission spectra of gases confined (but not adsorbed) within the pores of a 1.4-cm-thick silica xerogel sample have been recorded between 2.5 and 5 μm using a high-resolution Fourier transform spectrometer. This was done for pure CO, CO2, N2O, H2O, and CH4 at room temperature and pressures of a few hectopascals. Least-squares fits of measured absorption lines provide the optical-path lengths within the confined (LC) and free (LF) gas inside the absorption cell and the half width at half maximum ΓC of the lines of the confined gases. The values of LC and LF retrieved using numerous transitions of all studied species are very consistent. Furthermore, LC is in satisfactory agreement with values obtained from independent measurements, thus showing that reliable information on the open porosity volume can be retrieved from an optical experiment. The values of ΓC, here resulting from collisions of the molecules with the inner surfaces of the xerogel pores, are practically independent of the line for each gas and inversely proportional to the square root of the probed-molecule molar mass. This is a strong indication that, for the studied transitions, a single collision of a molecule with a pore surface is sufficient to change its rotational state. A previously proposed simple model, used for the prediction of the line shape, leads to satisfactory agreement with the observations. It also enables a determination of the average pore size, bringing information complementary to that obtained from nitrogen adsorption porosimetry. © 2013 American Physical Society.
BibTeX:
@article{VanderAuwera2013,
  author = {Vander Auwera, J. and Ngo, N.H. and El Hamzaoui, H. and Capoen, B. and Bouazaoui, M. and Ausset, P. and Boulet, C. and Hartmann, J.-M.},
  title = {Infrared absorption by molecular gases as a probe of nanoporous silica xerogel and molecule-surface collisions: Low-pressure results},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2013},
  volume = {88},
  article number = {042506},
  doi = {10.1103/PhysRevA.88.042506}
}
Abstract: The traditional multiconfiguration Hartree-Fock (MCHF) and configuration interaction (CI) methods are based on a single orthonormal orbital basis. For atoms with many closed core shells, or complicated shell structures, a large orbital basis is needed to saturate the different electron correlation effects such as valence, core-valence and correlation within the core shells. The large orbital basis leads to massive configuration state function (CSF) expansions that are difficult to handle, even on large computer systems. We show that it is possible to relax the orthonormality restriction on the orbital basis and break down the originally very large calculations into a series of smaller calculations that can be run in parallel. Each calculation determines a partitioned correlation function (PCF) that accounts for a specific correlation effect. The PCFs are built on optimally localized orbital sets and are added to a zero-order multireference (MR) function to form a total wave function. The expansion coefficients of the PCFs are determined from a low dimensional generalized eigenvalue problem. The interaction and overlap matrices are computed using a biorthonormal transformation technique (Verdebout et al 2010 J. Phys. B: At. Mol. Phys. 43 074017). The new method, called partitioned correlation function interaction (PCFI), converges rapidly with respect to the orbital basis and gives total energies that are lower than the ones from ordinary MCHF and CI calculations. The PCFI method is also very flexible when it comes to targeting different electron correlation effects. Focusing our attention on neutral lithium, we show that by dedicating a PCF to the single excitations from the core, spin- and orbital-polarization effects can be captured very efficiently, leading to highly improved convergence patterns for hyperfine parameters compared with MCHF calculations based on a single orthogonal radial orbital basis. By collecting separately optimized PCFs to correct the MR function, the variational degrees of freedom in the relative mixing coefficients of the CSFs building the PCFs are inhibited. The constraints on the mixing coefficients lead to small off-sets in computed properties such as hyperfine structure, isotope shift and transition rates, with respect to the correct values. By (partially) deconstraining the mixing coefficients one converges to the correct limits and keeps the tremendous advantage of improved convergence rates that comes from the use of several orbital sets. Reducing ultimately each PCF to a single CSF with its own orbital basis leads to a non-orthogonal CI approach. Various perspectives of the new method are given. © 2013 IOP Publishing Ltd.
BibTeX:
@article{Verdebout2013,
  author = {Verdebout, S. and Rynkun, P. and Jönsson, P. and Gaigalas, G. and Fischer, C.F. and Godefroid, M.},
  title = {A partitioned correlation function interaction approach for describing electron correlation in atoms},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2013},
  volume = {46},
  article number = {085003},
  doi = {10.1088/0953-4075/46/8/085003}
}
Abstract: The infrared spectrum of a sample containing 13C mono-substituted isotopologues of acetylene, H12C13CH, H12C13CD, D12C13CH and D 12C13 CD has been recorded in the 6130-6800 cm -1 region using a femto-Fourier transform-cavity enhanced absorption spectroscopy (femto-FT-CEAS) apparatus. Three bands for both H 12C13CD and D12C13CH were observed and analysed, namely 2ν1 - GS and associated hot bands from ν4 and ν5 . The assignment of the 2ν1 overtone already reported in the literature [J.L. Hardwick, Z.T. Martin, M.J. Pilkenton, E.N. Wolf, J. Mol. Spectrosc. 243, 10 (2007)] was considerably extended to higher J values. For the D12C13CD isotopologue, four bands were analysed, ν1 + ν2 + ν3 - GS and associated hot bands from ν4 and ν5 and 2ν1 + ν4 + ν5 - GS. © 2013 Taylor &amp; Francis.
BibTeX:
@article{Villa2013,
  author = {Villa, M. and Fusina, L. and Di Lonardo, G. and De Ghellinck D'Elseghem Vaernewijck, X. and Herman, M.},
  title = {Femto-FT-CEAS investigation of rare acetylene isotopologues (H 12C13CD, D12 C13 CH and D 12C13CD)},
  journal = {Molecular Physics},
  year = {2013},
  volume = {111},
  pages = {1972-1976},
  doi = {10.1080/00268976.2013.771805}
}
Abstract: We illustrate some of the difficulties that may be encountered when computing photodissociation and radiative association cross sections from the same time-dependent approach based on wavepacket propagation. The total and partial photodissociation cross sections from the 33 vibrational levels of the b 3Σ+ state of HeH+ towards the nine other 3Σ+ and 6 3Π n = 2, 3 higher lying electronic states are calculated, using the autocorrelation method introduced by Heller (1978 J. Chem. Phys. 68 3891) and the method based on the asymptotic behaviour of wavepackets introduced by Balint-Kurti et al (1990 J. Chem. Soc. Faraday Trans. 86 1741). The corresponding radiative association cross sections are extracted from the same calculations, and the photodissociation and radiative association rate constants are determined. © 2013 IOP Publishing Ltd.
BibTeX:
@article{Vranckx2013,
  author = {Vranckx, S. and Loreau, J. and Desouter-Lecomte, M. and Vaeck, N.},
  title = {Determination of photodissociation and radiative association cross sections from the same time-dependent calculation},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2013},
  volume = {46},
  article number = {155201},
  doi = {10.1088/0953-4075/46/15/155201}
}
Abstract: Atmospheric carbon monoxide (CO) distributions are controlled by anthropogenic emissions, biomass burning, transport and oxidation by reaction with the hydroxyl radical (OH). Quantifying trends in CO is therefore important for understanding changes related to all of these contributions. Here we present a comprehensive record of satellite observations from 2000 through 2011 of total column CO using the available measurements from nadir-viewing thermal infrared instruments: MOPITT, AIRS, TES and IASI. We examine trends for CO in the Northern and Southern Hemispheres along with regional trends for Eastern China, Eastern USA, Europe and India. We find that all the satellite observations are consistent with a modest decreasing trend ∼-1 % yr-1 in total column CO over the Northern Hemisphere for this time period and a less significant, but still decreasing trend in the Southern Hemisphere. Although decreasing trends in the United States and Europe have been observed from surface CO measurements, we also find a decrease in CO over E. China that, to our knowledge, has not been reported previously. Some of the interannual variability in the observations can be explained by global fire emissions, but the overall decrease needs further study to understand the implications for changes in anthropogenic emissions. © 2013 Author(s).
BibTeX:
@article{Worden2013,
  author = {Worden, H.M. and Deeter, M.N. and Frankenberg, C. and George, M. and Nichitiu, F. and Worden, J. and Aben, I. and Bowman, K.W. and Clerbaux, C. and Coheur, P.F. and De Laat, A.T.J. and Detweiler, R. and Drummond, J.R. and Edwards, D.P. and Gille, J.C. and Hurtmans, D. and Luo, M. and Martínez-Alonso, S. and Massie, S. and Pfister, G. and Warner, J.X.},
  title = {Decadal record of satellite carbon monoxide observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {837-850},
  doi = {10.5194/acp-13-837-2013}
}
Abstract: Suspended particles play an important role in coastal waters by controlling to a large extent the variability of the water inherent optical properties (IOPs). In this study, focused on the complex waters of the Southern North Sea, the relationships between the concentration, composition and size of suspended particles and their optical properties (light absorption, and attenuation in the visible and near-infrared spectral regions) are investigated. Over a one-year period, field measurements were carried out along regular transects from the Belgian to the English coasts to cover a wide gradient of water masses. Results show that the area can be divided into three geographical zones, each one having specific biogeochemical and optical properties: Scheldt coastal zone (SCZ), Middle of the Southern North Sea (MSNS) and Thames coastal zone (TCZ). Concentrations of organic (inorganic) particles were always higher in the SCZ (TCZ). The MSNS was characterized by a high proportion of organic particles in low concentration. The spectral shape of particle attenuation reveals a wide range from negative to positive slopes. Particle size distributions reveal a power-law shape along the coasts (especially in the TCZ) and a bimodal distribution in the MSNS notably during the spring phytoplankton bloom. This bimodal size distribution and more precisely a size peak around 7 μm results in an unexpected negative spectral slope of the particle attenuation coefficient. Variations in the particulate mass-specific IOPs between the three regions were observed to predominate over seasonal variations. The implications in terms of inversion of IOPs into biogeochemical parameters, such as chlorophyll a and total suspended matter, in coastal waters are discussed. © 2012 Elsevier Ltd.
BibTeX:
@article{Astoreca2012,
  author = {Astoreca, R. and Doxaran, D. and Ruddick, K. and Rousseau, V. and Lancelot, C.},
  title = {Influence of suspended particle concentration, composition and size on the variability of inherent optical properties of the Southern North Sea},
  journal = {Continental Shelf Research},
  year = {2012},
  volume = {35},
  pages = {117-128},
  doi = {10.1016/j.csr.2012.01.007}
}
BibTeX:
@article{Berger2012,
  author = {Berger, G. and Gelbcke, M. and Cauët, E. and Luhmer, M. and Nève, J. and Dufrasne, F.},
  title = {Corrigendum to "Synthesis of 15N-labeled vicinal diamines through N-activated chiral aziridines: Tools for the NMR study of platinum-based anticancer compounds" [Tetrahedron Lett. 54 (2013) 545-548]},
  journal = {Tetrahedron Letters},
  year = {2012},
  doi = {10.1016/j.tetlet.2014.11.086}
}
Abstract: In a previous article we have introduced an alternative perturbation scheme to the traditional one starting from the harmonic oscillator, rigid rotator Hamiltonian, to find approximate solutions of the spectral problem for rotation-vibration molecular Hamiltonians. The convergence of our method for the methane vibrational ground state rotational energy levels was quicker than that of the traditional method, as expected, and our predictions were quantitative. In this second article, we study the convergence of the ab initio calculation of effective dipole moments for methane within the same theoretical frame. The first order of perturbation when applied to the electric dipole moment operator of a spherical top gives the expression used in previous spectroscopic studies. Higher orders of perturbation give corrections corresponding to higher centrifugal distortion contributions and are calculated accurately for the first time. Two potential energy surfaces of the literature have been used for solving the anharmonic vibrational problem by means of the vibrational mean field configuration interaction approach. Two corresponding dipole moment surfaces were calculated in this work at a high level of theory. The predicted intensities agree better with recent experimental values than their empirical fit. This suggests that our ab initio dipole moment surface and effective dipole moment operator are both highly accurate. © 2012 American Institute of Physics.
BibTeX:
@article{Cassam-Chenai2012,
  author = {Cassam-Chenaï, P. and Liévin, J.},
  title = {Ab initio calculation of the rotational spectrum of methane vibrational ground state},
  journal = {Journal of Chemical Physics},
  year = {2012},
  volume = {136},
  article number = {174309},
  doi = {10.1063/1.4705278}
}
Abstract: The Car-Parrinello-based molecular dynamics (CPMD) method was used to investigate the ion-pairing behavior between Cl - and Al 3+ ions in an aqueous AlCl 3 solution containing 63 water molecules. A series of constrained simulations was carried out at 300 K for up to 16 ps each, with the internuclear separation (r Al-Cl) between the Al 3+ ion and one of the Cl - ions held constant. The calculated potential of mean force (PMF) of the Al 3+-Cl - ion pair shows a global minimum at r Al-Cl = 2.3 Å corresponding to a contact ion pair (CIP). Two local minima assigned to solvent-separated ion pairs (SSIPs) are identified at r Al-Cl = 4.4 and 6.0 Å. The positions of the free energy minima coincide with the hydration-shell intervals of the Al 3+ cation, suggesting that the Cl - ion is inclined to reside in regions with low concentrations of water molecules, that is, between the first and second hydration shells of Al 3+ and between the second shell and the bulk. A detailed analysis of the solvent structure around the Al 3+ and Cl - ions as a function of r Al-Cl is presented. The results are compared to structural data from X-ray measurements and unconstrained CPMD simulations of single Al 3+ and Cl - ions and AlCl 3 solutions. The dipole moments of the water molecules in the first and second hydration shells of Al 3+ and in the bulk region and those of Cl - ions were calculated as a function of r Al-Cl. Major changes in the electronic structure of the system were found to result from the removal of Cl - from the first hydration shell of the Al 3+ cation. Finally, two unconstrained CPMD simulations of aqueous AlCl 3 solutions corresponding to CIP and SSIP configurations were performed (17 ps, 300 K). Only minor structural changes were observed in these systems, confirming their stability. © 2012 American Chemical Society.
BibTeX:
@article{Cauet2012b,
  author = {Cauët, E. and Bogatko, S.A. and Bylaska, E.J. and Weare, J.H.},
  title = {Ion association in AlCl 3 aqueous solutions from constrained first-principles molecular dynamics},
  journal = {Inorganic Chemistry},
  year = {2012},
  volume = {51},
  pages = {10856-10869},
  doi = {10.1021/ic301346k}
}
Abstract: We present a summary of the research activities of the "Quantum Chemistry and Atomic Physics" theoretical group of the "Chimie Quantique et Photophysique" Laboratory at Université Libre de Bruxelles. We emphasize the links between the three orientations of the group: theoretical atomic spectroscopy, structure, and molecular dynamics and list the perspectives of our collaboration. © Springer-Verlag 2012.
BibTeX:
@article{Cauet2012a,
  author = {Cauët, E. and Carette, T. and Lauzin, C. and Li, J.G. and Loreau, J. and Delsaut, M. and Nazé, C. and Verdebout, S. and Vranckx, S. and Godefroid, M. and Liévin, J. and Vaeck, N.},
  title = {From atoms to biomolecules: A fruitful perspective},
  journal = {Theoretical Chemistry Accounts},
  year = {2012},
  volume = {131},
  pages = {1-17},
  doi = {10.1007/s00214-012-1254-3}
}
Abstract: Using Density Functional Theory approaches, we investigate the structure and spectroscopic signatures of sumanene, monooxosumanene and trioxosumanene, three synthesised bowl-shaped compounds. The simulated properties include geometries, charges, polarisabilities, infrared and UV/visible spectra as well as complexation energies. Refined approaches have been considered (anharmonic frequencies, state-specific solvent model, dispersion-corrected DFT...) and a valuable agreement with experimental reference values is reached for most properties. The evolution of the electronic features of sumanene upon oxidation has been rationalised. © 2011 Elsevier B.V. All rights reserved.
BibTeX:
@article{Cauet2012c,
  author = {Cauët, E. and Jacquemin, D.},
  title = {A theoretical spectroscopy investigation of oxosumanenes},
  journal = {Chemical Physics Letters},
  year = {2012},
  volume = {519-520},
  pages = {49-53},
  doi = {10.1016/j.cplett.2011.11.021}
}
Abstract: Ionization and charge migration in DNA play crucial roles in mechanisms of DNA damage caused by ionizing radiation, oxidizing agents and photo-irradiation. Therefore, an evaluation of the ionization properties of the DNA bases is central to the full interpretation and understanding of the elementary reactive processes that occur at the molecular level during the initial exposure and afterwards. Ab initio quantum mechanical (QM) methods have been successful in providing highly accurate evaluations of key parameters, such as ionization energies (IE) of DNA bases. Hence, in this study, we performed high-level QM calculations to characterize the molecular energy levels and potential energy surfaces, which shed light on ionization and charge migration between DNA bases. In particular, we examined the IEs of guanine, the most easily oxidized base, isolated and embedded in base clusters, and investigated the mechanism of charge migration over two and three stacked guanines. The IE of guanine in the human telomere sequence has also been evaluated. We report a simple molecular orbital analysis to explain how modifications in the base sequence are expected to change the efficiency of the sequence as a hole trap. Finally, the application of a hybrid approach combining quantum mechanics with molecular mechanics brings an interesting discussion as to how the native aqueous DNA environment affects the IE threshold of nucleobases.
BibTeX:
@article{Cauet2012,
  author = {Cauët, E. and Valiev, M. and Weare, J.H. and Liévin, J.},
  title = {Quantum mechanical calculations related to ionization and charge transfer in DNA},
  journal = {Journal of Physics: Conference Series},
  year = {2012},
  volume = {373},
  article number = {012003},
  doi = {10.1088/1742-6596/373/1/012003}
}
Abstract: We investigate possible mutations in the genetic code induced by cisplatin with an approach combining molecular dynamics (MD) and hybrid quantum mechanics/molecular mechanics (QM/MM) calculations. Specifically, the impact of platination on the natural tautomeric equilibrium in guanine-cytosine (GC) base pairs is assessed to disclose the possible role played by non-canonical forms in anti-tumour activity. To obtain valuable predictions, the main interactions present in a real DNA environment, namely hydration and stacking, are simultaneously taken into account. According to our results, the Pt-DNA adduct promotes a single proton transfer reaction in GC in the DNA sequence AGGC. Such rare tautomers might play an important role in the cisplatin biological activity since they meet the stability requirements necessary to promote a permanent mutation. This journal is © the Owner Societies 2012.
BibTeX:
@article{Ceron-Carrasco2012,
  author = {Cerón-Carrasco, J.P. and Jacquemin, D. and Cauët, E.},
  title = {Cisplatin cytotoxicity: A theoretical study of induced mutations},
  journal = {Physical Chemistry Chemical Physics},
  year = {2012},
  volume = {14},
  pages = {12457-12464},
  doi = {10.1039/c2cp40515f}
}
Abstract: Using an extended cavity diode laser referenced to a femtosecond frequency comb, the P(11) absorption line in the ν 1+ν 3 combination band of the most abundant isotopologue of pure acetylene was studied at temperatures of 296, 240, 200, 175, 165, 160, 155, and 150 K to determine pressure-dependent line shape parameters at these temperatures. The laser emission profile, the instrumental resolution, is a Lorentz function characterized by a half width at half the maximum emission (HWHM) of 8.3×10-6 cm-1 (or 250 kHz) for these measurements. Six collision models were tested in fitting the experimental data: Voigt, speed-dependent Voigt, Rautian-Sobel'man, Galatry, and two Rautian-Galatry hybrid models (with and without speed-dependence). Only the speed-dependent Voigt model was able to fit the data to the experimental noise level at all temperatures and for pressures between 3 and nearly 360 torr. The variations of the speed-dependent Voigt profile line shape parameters with temperature were also characterized, and this model accurately reproduces the observations over their entire range of temperature and pressure. © 2011 Springer-Verlag.
BibTeX:
@article{Cich2012,
  author = {Cich, M.J. and McRaven, C.P. and Lopez, G.V. and Sears, T.J. and Hurtmans, D. and Mantz, A.W.},
  title = {Temperature-dependent pressure broadened line shape measurements in the ν 1+ν 3 band of acetylene using a diode laser referenced to a frequency comb},
  journal = {Applied Physics B: Lasers and Optics},
  year = {2012},
  volume = {109},
  pages = {373-384},
  doi = {10.1007/s00340-011-4829-0}
}
Abstract: Thermal infrared sounding of sulphur dioxide (SO 2) from space has gained appreciation as a valuable complement to ultraviolet sounding. There are several strong absorption bands of SO 2 in the infrared, and atmospheric sounders, such as AIRS (Atmospheric Infrared Sounder), TES (Tropospheric Emission Spectrometer) and IASI (Infrared Atmospheric Sounding Interferometer) have the ability to globally monitor SO 2 abundances. Most of the observed SO 2 is found in volcanic plumes. In this paper we outline a novel algorithm for the sounding of SO 2 above ∼5 km altitude using high resolution infrared sounders and apply it to measurements of IASI. The main features of the algorithm are a wide applicable total column range (over 4 orders of magnitude, from 0.5 to 5000 dobson units), a low theoretical uncertainty (3-5%) and near real time applicability. We make an error analysis and demonstrate the algorithm on the recent eruptions of Sarychev, Kasatochi, Grimsvötn, Puyehue-Cordón Caulle and Nabro. © 2012 Author(s). CC Attribution 3.0 License.
BibTeX:
@article{Clarisse2012,
  author = {Clarisse, L. and Hurtmans, D. and Clerbaux, C. and Hadji-Lazaro, J. and Ngadi, Y. and Coheur, P.-F.},
  title = {Retrieval of sulphur dioxide from the infrared atmospheric sounding interferometer (IASI)},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {581-594},
  doi = {10.5194/amt-5-581-2012}
}
Abstract: Emission spectra of the A 2Π-X 2Σ + (red) and B 2Σ +-X 2Σ + (violet) systems of the 12C 15N molecule have been investigated in the 4500-26 000 cm -1 spectral region at high resolution using a Fourier transform spectrometer. In all, 22 bands of the A-X system and six bands of the B-X system have been rotationally analyzed providing a set of molecular constants for the v″ = 0-5, v′ = 0-4 and v′ = 0-3 levels of the X, A and B states, respectively. © 2012 Elsevier B.V. All rights reserved.
BibTeX:
@article{Colin2012,
  author = {Colin, R. and Bernath, P.F.},
  title = {High resolution Fourier transform emission spectroscopy of the A 2Π-X 2Σ + and B 2Σ +-X 2Σ + systems of the 12C 15N free radical},
  journal = {Journal of Molecular Spectroscopy},
  year = {2012},
  volume = {273},
  pages = {30-33},
  doi = {10.1016/j.jms.2012.01.007}
}
Abstract: High-resolution water vapor absorption spectra have been measured at room temperature in the 8800-11,600cm -1 spectral region. They were obtained using the mobile BRUKER IFS 120M Fourier transform spectrometer (FTS) from ULB-SCQP coupled to the 50m base long multiple reflection White type cell in GSMA laboratory. The absorption path was 600m and different H 2O/HDO/D 2O mixtures were used. Measurements of line positions, intensities and self-broadening coefficients were performed for the HD 16O isotopologue. 6464 rovibrational assignment of the observed lines was made on the basis of global variational predictions and allowed the identification of new energy levels. 3ν 3, 2ν 1+ν 3, 3ν 1+ν 2, ν 1+2ν 3 and 2ν 2+2ν 3 are the five strongest bands. The present paper provides a complementary data set on water vapor for atmospheric and astrophysical applications. © 2012 Elsevier Ltd.
BibTeX:
@article{Daumont2012,
  author = {Daumont, L. and Jenouvrier, A. and Mikhailenko, S. and Carleer, M. and Hermans, C. and Fally, S. and Vandaele, A.C.},
  title = {High resolution Fourier transform spectroscopy of HD 16O: Line positions, absolute intensities and self broadening coefficients in the 8800-11,600cm -1 spectral region},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2012},
  volume = {113},
  pages = {878-888},
  doi = {10.1016/j.jqsrt.2012.02.017}
}
Abstract: Proofs of principle spectra of C2H4, N2O and C2H2, including H12C13CH in natural abundance, are reported, recorded in the 1.6 mm range in an Ar supersonic expansion using femto-Fourier transform-cavity enhanced absorption spectroscopy. The effective absorption pathlength in the jet-cooled sample is up to 78m and the optimal S/N is over 2300. The data processing is detailed. Saturation effects are reported for the C2H2 bands. spectroscopy © 2012 Taylor and Francis.
BibTeX:
@article{DeGhellinckDElseghemVaernewijck2012b,
  author = {De Ghellinck D'Elseghem Vaernewijck, X. and Golebiowski, D. and Herman, M.},
  title = {Femto-Fourier transform-cavity enhanced absorption spectroscopy in a supersonic expansion},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2735-2741},
  doi = {10.1080/00268976.2012.701342}
}
Abstract: Near infrared spectra of a carbon dioxide sample enriched with oxygen-17 have been recorded using a highresolution continuous scan Fourier transform interferometer fitted with a femto OPO/Idler laser source. Cavity enhanced absorption has been achieved in a static gas cell allowing an optimal rms noise equivalent absorption of 1.2×10-10 cm-1 Hz -1/2 per spectral element to be reached, corresponding to αmin=10-8 cm-1. Spectra were calibrated against acetylene reference line positions. Three bands in the 3v 1+v3 tetrad in both 12C17O 2 and 12C17O18O have been identified and rotationally analyzed, as well as some related hot bands, eight of which are newly reported and three with their analysis updated compared with a preliminary report (X. de Ghellinck d'Elseghem Vaernewijck et al., Chem. Phys. Lett. 514, 29 (2011)). © 2012 Taylor and Francis.
BibTeX:
@article{DeGhellinckDElseghemVaernewijck2012,
  author = {De Ghellinck D'Elseghem Vaernewijck, X. and Kassi, S. and Herman, M.},
  title = {17O12C17O and 18O 12C17O spectroscopy in the 1.6 μm region},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2665-2671},
  doi = {10.1080/00268976.2012.705346}
}
Abstract: A femto-OPO laser fitted to a high-finesse cavity and a Fourier transform spectrometer to perform femto-FT-CEAS (for femto-Fourier transform-cavity enhanced spectroscopy) was used to record high overtones of carbon disulfide with a minimal rms equivalent absorption coefficient of 1.2 × 10 -11 cm-1 Hz-1/2 per spectral element. New vibrational states are reported for 12C32S2 and 12C32S34S and new or improved rotational constants are obtained, for the v1v2l2v3 = 3003, 2203, 0114 and 4003 states in 12C32S2 and 3003 state in 32S12C34S. © 2012 Elsevier Inc. All rights reserved.
BibTeX:
@article{DeGhellinckDElseghemVaernewijck2012a,
  author = {De Ghellinck D'Elseghem Vaernewijck, X. and Kongolo Tshikala, P. and Lepère, M. and Herman, M.},
  title = {Femto-FT-CEAS applied to carbon disulfide around 1.54 μm},
  journal = {Journal of Molecular Spectroscopy},
  year = {2012},
  volume = {282},
  pages = {27-29},
  doi = {10.1016/j.jms.2012.10.006}
}
Abstract: The IASI (Infrared Atmospheric Sounding Interferometer) nadir-looking thermal infrared sounder onboard MetOp-A enables the monitoring of atmospheric constituents on a global scale. This paper presents a quality assessment of IASI CO profiles retrieved by the two different retrieval algorithms SOFRID and FORLI, by an intercomparison with airborne in-situ CO profiles from the MOZAIC program for the 2008-2009 period. Lower (surface-480 hPa) and upper tropospheric partial column (480-225 hPa) comparisons as well as profile comparisons are made. The retrieval errors of the IASI products are less than 21% in the lower troposphere and less than 10% in the upper troposphere. A statistical analysis shows similar correlation coefficients for the two retrieval algorithms and smoothed MOZAIC of r ∼ 0.8 and r ∼ 0.7 in the lower and upper troposphere respectively. Comparison with smoothed MOZAIC data of the temporal variation of the CO profiles at the airports of Frankfurt and Windhoek demonstrates that the IASI products are able to capture the seasonal variability at these sites. At Frankfurt SOFRID (respectively FORLI) is positively biased by 10.5% (13.0%) compared to smoothed MOZAIC in the upper (lower) troposphere, and the limited sensitivity of the IASI instrument to the boundary layer when thermal contrast is low is identified. At Windhoek, the impact of the vegetation fires in Southern Africa from July to November is captured by both SOFRID and FORLI, with an overestimation of the CO background values (fire maxima) by SOFRID (FORLI) by 12.8% (10%). Profile comparisons at Frankfurt and Windhoek show that the largest discrepancies are found between the two IASI products and MOZAIC for the nighttime retrievals. © 2012 Author(s).
BibTeX:
@article{DeWachter2012,
  author = {De Wachter, E. and Barret, B. and Le Flochmoën, E. and Pavelin, E. and Matricardi, M. and Clerbaux, C. and Hadji-Lazaro, J. and George, M. and Hurtmans, D. and Coheur, P.-F. and Nedelec, P. and Cammas, J.P.},
  title = {Retrieval of MetOp-A/IASI CO profiles and validation with MOZAIC data},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {2843-2857},
  doi = {10.5194/amt-5-2843-2012}
}
Abstract: Building upon previous studies, we re-investigated the ethane spectrum between 1330 and 1610 cm -1 by combining unapodized spectra obtained at room temperature with a Bruker Fourier transform spectrometer (FTS) in Brussels and at 131 K with a Bruker FTS in Pasadena. The maximum optical path differences (MOPD) of the two datasets were 450 and 323.7 cm, corresponding to spectral resolutions of 0.0020 and 0.0028 cm -1, respectively. Of the 15,000 lines observed, over 4592 transitions were assigned to the ν 6 (at 1379 cm -1), ν 8 (at 1472 cm -1), ν 4ν 12 (at 1481 cm -1) and 2ν 4ν 9 (at 1388 cm -1) bands, and another 1044 transitions were located for the ν 4ν 8- ν 4 hot band (at 1472 cm -1). Our new analysis included an improved implementation of the Hamiltonian calculation needed to interpret the complex spectral structures caused by numerous interactions affecting these four modes of vibration. From these results, we created the first line-by-line database containing the molecular parameters for over 20,000 12C 2H 6 transitions at 7 μm. © 2011 Elsevier Ltd. All rights reserved.
BibTeX:
@article{DiLauro2012,
  author = {Di Lauro, C. and Lattanzi, F. and Brown, L.R. and Sung, K. and Vander Auwera, J. and Mantz, A.W. and Smith, M.A.H.},
  title = {High resolution investigation of the 7 μm region of the ethane spectrum},
  journal = {Planetary and Space Science},
  year = {2012},
  volume = {60},
  pages = {93-101},
  doi = {10.1016/j.pss.2011.01.008}
}
Abstract: Spectroscopic results are presented concerning the 2CH excitation around 1.5 mm in van der Waals complexes of acetylene (C2H2) with Ar, Kr, N2, CO2, N2O and C2H 2. Many are reviewed from the literature, with some updates. Previously unpublished results are also presented, concerning the mechanism of formation of C2H2-Ar in the supersonic jet, the assignment of new spectral structures in C2H2-N2O, and the first observation of 2CH excitation in C2H2-Ne, C 2H2-H2O, C2H2-D 2O and (C2H2)n. Lifetimes of these 2CH vibrationally excited dimers are discussed. © 2012 Taylor and Francis.
BibTeX:
@article{Didriche2012a,
  author = {Didriche, K. and Földes, T. and Lauzin, C. and Golebiowski, D. and Liévin, J. and Herman, M.},
  title = {Experimental 2CH excitation in acetylene-containing van der Waals complexes},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2781-2796},
  doi = {10.1080/00268976.2012.705347}
}
Abstract: A preliminary analysis of the 2CH excitation band in C2H 2-N2O in the 1.5 mm range (K. Didriche, C. Lauzin, P. Macko, M. Herman and W.J. Lafferty, Chem. Phys. Letters 469, 35 (2009).), only considering 117 low J-, and Ka-vibration-rotation lines, is significantly extended thanks to the analysis of new spectra including very regular series of lines with J/Ka up to 31/15. 1271 b-type lines were assigned. Perturbations are briefly discussed. The rotational temperature in the experiments is estimated to be 20K and the upper state mean half-time is 1.6 ns for non perturbed levels. The previous analyses of the 2CH + torsion band in C2H2-N2O and in C2H 2-CO2 (C. Lauzin, K. Didriche, T. Földes and M. Herman, Mol. Phys. 109, 2105 (2011).), are also extended to include 286 and 234 lines, respectively, also correcting for calibration errors. New rotational constants are obtained using a rigid rotor Hamiltonian by simultaneously fitting the ground, 2CH and 2CH + torsion states in C2H2-N 2O, and the latter state, only, in C2H2-CO 2. © 2012 Taylor and Francis.
BibTeX:
@article{Didriche2012,
  author = {Didriche, K. and Földes, T. and Lauzin, C. and Herman, M.},
  title = {The 2CH excitation band in C2H2-N2O and 2CH+torsion combination bands in C2H2-N2O and C2H2-CO2},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2773-2779},
  doi = {10.1080/00268976.2012.713523}
}
Abstract: CW-cavity ring down spectroscopy was used to record the spectrum of 12C 2H 2-N 2 in a free jet expansion around the 2CH acetylene band. Twenty lines were assigned thanks to combination differences, which were combined with literature values leading to the retrieval of ground state rotational constants consistent for a broader set of J″. Effective rotational constants, the band origin and the estimation of the lifetime of the perturbed upper state are determined. © 2012 Elsevier B.V. All rights reserved.
BibTeX:
@article{Didriche2012b,
  author = {Didriche, K. and Lauzin, C. and Földes, T.},
  title = {Observation of the linear C 2H 2-N 2 van der Waals complex in the 2CH range using CW-CRDS},
  journal = {Chemical Physics Letters},
  year = {2012},
  volume = {530},
  pages = {31-34},
  doi = {10.1016/j.cplett.2012.01.072}
}
Abstract: Three scientific ozone products from the Infrared Atmospheric Sounding Interferometer (IASI) aboard MetOp-A, retrieved in three different research teams (LA, LATMOS/ULB, LISA) with different retrieval schemes, are characterized and validated using ozonesondes measurements. The characteristics of the products are analyzed in terms of retrieval sensitivity, systematic and random errors, and ability to retrieve the natural variability of ozone and focus on different partial columns from the lower troposphere up to 30 km. The validation covers the midlatitudes and the tropics and the period from January to December 2008. The products present degrees of freedom (DOF) in the troposphere between 1 and 1.2 on average in the midlatitudes and between 1 and 1.4 in the tropics. The DOF are distributed differently on the vertical depending on the profiles and the season: summer leading to a better sensitivity to the lower troposphere, as expected. The error estimates range between 10 and 20% from the lower tropospheric partial columns (0-6 km and 0-8 km for the midlatitudes and the tropics respectively) to the UTLS partial columns (8-16 km and 11-20 km for the midlatitudes and the tropics respectively) for all the products and are about 5% in the stratosphere (16-30 km) and for the column up to 30 km. The main feature that arises from the comparison with the ozonesondes is a systematic overestimation of ozone in the UTLS (between 10 and 25%) by the three products in the midlatitudes and the tropics, attributed to the moderate vertical resolution of IASI and possibly to spectroscopic inconsistencies. The ability of the products to reproduce natural variability of tropospheric ozone is fairly good and depends on the considered season and region. © 2012 Author(s).
BibTeX:
@article{Dufour2012,
  author = {Dufour, G. and Eremenko, M. and Griesfeller, A. and Barret, B. and Leflochmoën, E. and Clerbaux, C. and Hadji-Lazaro, J. and Coheur, P.-F. and Hurtmans, D.},
  title = {Validation of three different scientific ozone products retrieved from IASI spectra using ozonesondes},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {611-630},
  doi = {10.5194/amt-5-611-2012}
}
Abstract: First-principles dynamics simulations (DFT, PBE96, and PBE0) and electron scattering calculations (FEFF9) provide near-quantitative agreement with new and existing XAFS measurements for a series of transition-metal ions interacting with their hydration shells via complex mechanisms (high spin, covalency, charge transfer, etc.). This analysis does not require either the development of empirical interparticle interaction potentials or structural models of hydration. However, it provides consistent parameter-free analysis and improved agreement with the higher-R scattering region (first- and second-shell structure, symmetry, dynamic disorder, and multiple scattering) for this comprehensive series of ions. DFT+GGA MD methods provide a high level of agreement. However, improvements are observed when exact exchange is included. Higher accuracy in the pseudopotential description of the atomic potential, including core polarization and reducing core radii, was necessary for very detailed agreement. The first-principles nature of this approach supports its application to more complex systems. © 2012 American Chemical Society.
BibTeX:
@article{Fulton2012,
  author = {Fulton, J.L. and Bylaska, E.J. and Bogatko, S. and Balasubramanian, M. and Cauët, E. and Schenter, G.K. and Weare, J.H.},
  title = {Near-quantitative agreement of model-free DFT-MD predictions with XAFS observations of the hydration structure of highly charged transition-metal ions},
  journal = {Journal of Physical Chemistry Letters},
  year = {2012},
  volume = {3},
  pages = {2588-2593},
  doi = {10.1021/jz3008497}
}
Abstract: The global distribution of dust column burden derived from MODIS Deep Blue aerosol products is compared to NH 3 column burden retrieved from IASI infrared spectra. We found similarities in their spatial distributions, in particular their hot spots are often collocated over croplands and to a lesser extent pastures. Globally, we found 22% of dust burden collocated with NH 3, with only 1% difference between land-use databases. This confirms the importance of anthropogenic dust from agriculture. Regionally, the Indian subcontinent has the highest amount of dust mixed with NH 3 (26%), mostly over cropland and during the pre-monsoon season. North Africa represents 50% of total dust burden but accounts for only 4% of mixed dust, which is found over croplands and pastures in Sahel and the coastal region of the Mediterranean. In order to evaluate the radiative effect of this mixing on dust optical properties, we derive the mass extinction efficiency for various mixtures of dust and NH 3, using AERONET sunphotometers data. We found that for dusty days the coarse mode mass extinction efficiency decreases from 0.62 to 0.48 m 2 g -1 as NH 3 burden increases from 0 to 40 mg m -2. The fine mode extinction efficiency, ranging from 4 to 16 m 2 g -1, does not appear to depend on NH 3 concentration or relative humidity but rather on mineralogical composition and mixing with other aerosols. Our results imply that a significant amount of dust is already mixed with ammonium salt before its long range transport. This in turn will affect dust lifetime, and its interactions with radiation and cloud properties. © 2012 Author(s).
BibTeX:
@article{Ginoux2012,
  author = {Ginoux, P. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Dubovik, O. and Hsu, N.C. and Van Damme, M.},
  title = {Mixing of dust and NH 3 observed globally over anthropogenic dust sources},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {7351-7363},
  doi = {10.5194/acp-12-7351-2012}
}
Abstract: We use in situ observations from the Interagency Monitoring of PROtected Visual Environments (IMPROVE) network, the Midwest Ammonia Monitoring Project, 11 surface site campaigns as well as Infrared Atmospheric Sounding Interferometer (IASI) satellite measurements with the GEOS-Chem model to investigate inorganic aerosol loading and atmospheric ammonia concentrations over the United States. IASI observations suggest that current ammonia emissions are underestimated in California and in the springtime in the Midwest. In California this underestimate likely drives the underestimate in nitrate formation in the GEOS-Chem model. However in the remaining continental United States we find that the nitrate simulation is biased high (normalized mean bias &gt; Combining double low line 1.0) year-round, except in Spring (due to the underestimate in ammonia in this season). None of the uncertainties in precursor emissions, the uptake efficiency of N 2O 5 on aerosols, OH concentrations, the reaction rate for the formation of nitric acid, or the dry deposition velocity of nitric acid are able to explain this bias. We find that reducing nitric acid concentrations to 75% of their simulated values corrects the bias in nitrate (as well as ammonium) in the US. However the mechanism for this potential reduction is unclear and may be a combination of errors in chemistry, deposition and sub-grid near-surface gradients. This "updated" simulation reproduces PM and ammonia loading and captures the strong seasonal and spatial gradients in gas-particle partitioning across the United States. We estimate that nitrogen makes up 15-35% of inorganic fine PM mass over the US, and that this fraction is likely to increase in the coming decade, both with decreases in sulfur emissions and increases in ammonia emissions. © 2012 Author(s).
BibTeX:
@article{Heald2012,
  author = {Heald, C.L. and Collett Jr., J.L. and Lee, T. and Benedict, K.B. and Schwandner, F.M. and Li, Y. and Clarisse, L. and Hurtmans, D.R. and Van Damme, M. and Clerbaux, C. and Coheur, P.-F. and Philip, S. and Martin, R.V. and Pye, H.O.T.},
  title = {Atmospheric ammonia and particulate inorganic nitrogen over the United States},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {10295-10312},
  doi = {10.5194/acp-12-10295-2012}
}
Abstract: The UK Met Office's Numerical Atmospheric-dispersion Modeling Environment (NAME) is used both operationally and for research investigations. It has previously been used to model volcanic ash at the London Volcanic Ash Advisory Centre (VAAC), including that from the eruptions in Iceland of Eyjafjallajökull in 2010 and Grímsvtn in 2011. In this paper, the ability of NAME to model the release and dispersion of volcanic SO2, the chemical processes leading to the production of sulphate aerosol, and the subsequent dispersion of sulphate aerosol, has been investigated. Sensitivity tests were carried out to investigate the suitability of the NAME chemistry scheme for use in both the troposphere and the stratosphere. The eruptions of Sarychev in 2009, Kasatochi in 2008 and Eyjafjallajökull in 2010 were simulated and results for SO2 column density and sulphate aerosol optical depth (AOD) were compared with satellite retrievals. NAME results compare favorably with available observations in terms of both geographical distribution and magnitude for all three cases. The NAME modeled values of SO2 show a correlation of 0.8 with the corresponding observations for Sarychev. Ninety percent of modeled values of northern hemisphere averaged sulphate AOD are within a factor of 2 of those observed for Kasatochi and 71% are within a factor of 2 of those observed for Sarychev. Although significant uncertainties are present in both the model and observations, this work demonstrates that NAME's current chemistry scheme shows promise as a tool for modeling SO2 and sulphate from volcanoes. © 2012 by the American Geophysical Union.
BibTeX:
@article{Heard2012,
  author = {Heard, I.P.C. and Manning, A.J. and Haywood, J.M. and Witham, C. and Redington, A. and Jones, A. and Clarisse, L. and Bourassa, A.},
  title = {A comparison of atmospheric dispersion model predictions with observations of SO2 and sulphate aerosol from volcanic eruptions},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2012},
  volume = {117},
  article number = {D00U22},
  doi = {10.1029/2011JD016791}
}
BibTeX:
@article{Herman2012,
  author = {Herman, M.},
  title = {Foreword},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2619-2620},
  doi = {10.1080/00268976.2012.707015}
}
Abstract: The first Infrared Atmospheric Sounding Interferometer (IASI) was launched in October 2006 on the European Organization for the Exploitation of Meteorological Satellites' (EUMETSAT) Meteorological Operation (MetOp)-A satellite. The instrument and its successors will continue to operate until 2020 on the current MetOp platform and two follow-on satellites. The stability of the instrument is monitored routinely by the CNES Technical Expertise Center, using onboard measurements, and by EUMETSAT, where stable, clear fields of view are compared with simulated radiances from numerical weather prediction model output. Routine monitoring of IASI data and calibration and validation activities by CNES and EUMETSAT ensure full characterization of the instrument and verify that the performance meets the requirements. In-depth evaluation is routinely performed by comparing IASI with other instruments, such as AVHRR and the High Resolution Infrared Radiation Sounder (HIRS) on the MetOp platform.
BibTeX:
@article{Hilton2012,
  author = {Hilton, F. and Armante, R. and August, T. and Barnet, C. and Bouchard, A. and Camy-Peyret, C. and Capelle, V. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Collard, A. and Crevoisier, C. and Dufour, G. and Edwards, D. and Faijan, F. and Fourrié, N. and Gambacorta, A. and Goldberg, M. and Guidard, V. and Hurtmans, D. and Illingworth, S. and Jacquinet-Husson, N. and Kerzenmacher, T. and Klaes, D. and Lavanant, L. and Masiello, G. and Matricardi, M. and McNally, A. and Newman, S. and Pavelin, E. and Payan, S. and Péquignot, E. and Peyridieu, S. and Phulpin, T. and Remedios, J. and Schlüssel, P. and Serio, C. and Strow, L. and Stubenrauch, C. and Taylor, J. and Tobin, D. and Wolf, W. and Zhou, D.},
  title = {Hyperspectral earth observation from IASI},
  journal = {Bulletin of the American Meteorological Society},
  year = {2012},
  volume = {93},
  pages = {347-370},
  doi = {10.1175/BAMS-D-11-00027.1}
}
Abstract: This paper lays down the theoretical bases and the methods used in the Fast Optimal Retrievals on Layers for IASI (FORLI) software, which is developed and maintained at the "Université Libre de Bruxelles" (ULB) with the support of the "Laboratoire Atmosphères, Milieux, Observations Spatiales" (LATMOS) to process radiance spectra from the Infrared Atmospheric Sounding Interferometer (IASI) in the perspective of local to global chemistry applications. The forward radiative transfer model (RTM) and the retrieval approaches are formulated and numerical approximations are described. The aim of FORLI is near-real-time provision of global scale concentrations of trace gases from IASI, either integrated over the altitude range of the atmosphere (total columns) or vertically resolved. To this end, FORLI uses precalculated table of absorbances. At the time of writing three gas-specific versions of this algorithm have been set up: FORLI-CO, FORLI-O 3 and FORLI-HNO 3. The performances of each are reviewed and illustrations of results and early validations are provided, making the link to recent scientific publications. In this paper we stress the challenges raised by near-real-time processing of IASI, shortly describe the processing chain set up at ULB and draw perspectives for future developments and applications. © 2012 Elsevier Ltd.
BibTeX:
@article{Hurtmans2012,
  author = {Hurtmans, D. and Coheur, P.-F. and Wespes, C. and Clarisse, L. and Scharf, O. and Clerbaux, C. and Hadji-Lazaro, J. and George, M. and Turquety, S.},
  title = {FORLI radiative transfer and retrieval code for IASI},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2012},
  volume = {113},
  pages = {1391-1408},
  doi = {10.1016/j.jqsrt.2012.02.036}
}
Abstract: Low-energy electrons (LEEs) play an important role in nanolithography, atmospheric chemistry, and DNA radiation damage. Previously, the cleavage of specific chemical bonds triggered by LEEs has been demonstrated in a variety of small organic molecules such as halogenated benzenes and DNA nucleobases. Here we present a strategy that allows for the first time to visualize the electron-induced dissociation of single chemical bonds within complex, but well-defined self-assembled DNA nanostructures. We employ atomic force microscopy to image and quantify LEE-induced bond dissociations within specifically designed oligonucleotide targets that are attached to DNA origami templates. In this way, we use a highly selective approach to compare the efficiency of the electron-induced dissociation of a single disulfide bond with the more complex cleavage of the DNA backbone within a Π dinucleotide sequence. This novel technique enables the fast and parallel determination of DNA strand break yields with unprecedented control over the DNA's primary and secondary structure. Thus the detailed investigation of DNA radiation damage in its most natural environment, e.g., DNA nucleosomes constituting the chromatin, now becomes feasible. © 2012 American Chemical Society.
BibTeX:
@article{Keller2012,
  author = {Keller, A. and Bald, I. and Rotaru, A. and Cauët, E. and Gothelf, K.V. and Besenbacher, F.},
  title = {Probing electron-induced bond cleavage at the single-molecule level using DNA origami templates},
  journal = {ACS Nano},
  year = {2012},
  volume = {6},
  pages = {4392-4399},
  doi = {10.1021/nn3010747}
}
Abstract: Carbon monoxide (CO) is retrieved daily and globally from space-borne IASI radiance spectra using the Fast Optimal Retrievals on Layers for IASI (FORLI) software developed at the Université Libre de Bruxelles (ULB). The IASI CO total column product for 2008 from the most recent FORLI retrieval version (20100815) is evaluated using correlative CO profile products retrieved from ground-based solar absorption Fourier transform infrared (FTIR) observations at the following FTIR spectrometer sites from the Network for the Detection of Atmospheric Composition Change (NDACC): Ny-Ã..lesund, Kiruna, Bremen, Jungfraujoch, Izaña and Wollongong. In order to have good statistics for the comparisons, we included all IASI data from the same day, within a 100 km radius around the ground-based stations. The individual ground-based data were adjusted to the lowest altitude of the co-located IASI CO profiles. To account for the different vertical resolutions and sensitivities of the ground-based and satellite measurements, the averaging kernels associated with the various retrieved products have been used to properly smooth coincident data products. It has been found that the IASI CO total column products compare well on average with the co-located ground-based FTIR total columns at the selected NDACC sites and that there is no significant bias for the mean values at all stations. © 2012 Author(s).
BibTeX:
@article{Kerzenmacher2012,
  author = {Kerzenmacher, T. and Dils, B. and Kumps, N. and Blumenstock, T. and Clerbaux, C. and Coheur, P.-F. and Demoulin, P. and García, O. and George, M. and Griffith, D.W.T. and Hase, F. and Hadji-Lazaro, J. and Hurtmans, D. and Jones, N. and Mahieu, E. and Notholt, J. and Paton-Walsh, C. and Raffalski, U. and Ridder, T. and Schneider, M. and Servais, C. and De Mazière, M.},
  title = {Validation of IASI FORLI carbon monoxide retrievals using FTIR data from NDACC},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {2751-2761},
  doi = {10.5194/amt-5-2751-2012}
}
Abstract: This work evaluates the IASI CO product against independent in-situ aircraft data from the MOZAIC program and the POLARCAT aircraft campaign. The validation is carried out by analysing the impact of assimilation of eight months of IASI CO columns retrieved for the period of May to December 2008 into the global chemistry transport model LMDz-INCA. A modelling system based on a sub-optimal Kalman filter was developed and a specific treatment that takes into account the representativeness of observations at the scale of the model grid is applied to the IASI CO columns and associated errors before their assimilation in the model. Comparisons of the assimilated CO profiles with in situ CO measurements indicate that the assimilation leads to a considerable improvement of the model simulations in the middle troposphere as compared with a control run with no assimilation. Model biases in the simulation of background values are reduced and improvement in the simulation of very high concentrations is observed. The improvement is due to the transport by the model of the information present in the IASI CO retrievals. Our analysis also shows the impact of assimilation of CO on the representation of transport into the Arctic region during the POLARCAT summer campaign. A considerable increase in CO mixing ratios over the Asian source region was observed when assimilation was used leading to much higher values of CO during the cross-pole transport episode. These higher values are in good agreement with data from the POLARCAT flights that sampled this plume. © 2012 Author(s).
BibTeX:
@article{Klonecki2012,
  author = {Klonecki, A. and Pommier, M. and Clerbaux, C. and Ancellet, G. and Cammas, J.-P. and Coheur, P.-F. and Cozic, A. and Diskin, G.S. and Hadji-Lazaro, J. and Hauglustaine, D.A. and Hurtmans, D. and Khattatov, B. and Lamarque, J.-F. and Law, K.S. and Nedelec, P. and Paris, J.-D. and Podolske, J.R. and Prunet, P. and Schlager, H. and Szopa, S. and Turquety, S.},
  title = {Assimilation of IASI satellite CO fields into a global chemistry transport model for validation against aircraft measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {4493-4512},
  doi = {10.5194/acp-12-4493-2012}
}
Abstract: The SPIRALE and SWIR balloon-borne instruments were launched in the Arctic polar region (near Kiruna, Sweden, 67.9° N-21.1° E) during summer on 7 and 24 August 2009 and on 14 August 2009, respectively. The SPIRALE instrument performed in situ measurements of several trace gases including CO and O 3 at altitudes between 9 and 34 km, with very high vertical resolution (∼ 5 m). The SWIR-balloon instrument measured total and partial column of several species including CO. The CO stratospheric profile from SPIRALE for 7 August 2009 shows some specific structures with large concentrations in the low levels (potential temperatures between 320 and 380 K, i.e. 10-14 km height). These structures are not present in the CO vertical profile of SPIRALE for 24 August 2009, for which the volume mixing ratios are typical from polar latitudes (∼ 30 ppb). CO total columns retrieved from the IASI-MetOp satellite sounder for the three dates of flights are used to understand this CO variability. SPIRALE and SWIR CO partial columns between 9 and 34 km are compared, allowing us to confirm that the enhancement of CO is localised in the stratosphere. The measurements are also investigated in terms of CO:O3 correlations and using several modelling approaches (trajectory calculations, potential vorticity fields, results of chemistry transport model) in order to characterize the origin of the air masses sampled. The emission sources are qualified in terms of source type (fires, urban pollution) using NH3 and CO measurements from IASI-MetOp and fires detection from MODIS on board the TERRA/AQUA satellite. The results give strong evidence that the unusual abundance of CO on 7 August is due to surface pollution plumes from East Asia and North America transporting to the upper troposphere and then entering the lower stratosphere by isentropic advection. This study strengthens evidence that the composition of low polar stratosphere in summer may be affected by anthropogenic surface emissions through long-range transport. © 2012 Author(s).
BibTeX:
@article{Krysztofiak2012,
  author = {Krysztofiak, G. and Thiéblemont, R. and Huret, N. and Catoire, V. and Té, Y. and Jégou, F. and Coheur, P.F. and Clerbaux, C. and Payan, S. and Drouin, M.A. and Robert, C. and Jeseck, P. and Attié, J.-L. and Camy-Peyret, C.},
  title = {Detection in the summer polar stratosphere of pollution plume from East Asia and North America by balloon-borne in situ CO measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {11889-11906},
  doi = {10.5194/acp-12-11889-2012}
}
Abstract: In this paper we retrieve atmospheric HDO, H2O concentrations and their ratio δD from IASI radiances spectra. Our method relies on an existing radiative transfer model (Atmosphit) and an optimal estimation inversion scheme, but goes further than our previous work by explicitly considering correlations between the two species. A global HDO and H 2O a priori profile together with a covariance matrix were built from daily LMDz-iso model simulations of HDO and H2O profiles over the whole globe and a whole year. The retrieval parameters are described and characterized in terms of errors. We show that IASI is mostly sensitive to δD in the middle troposphere and allows retrieving δD for an integrated 3-6 km column with an error of 38‰ on an individual measurement basis. We examine the performance of the retrieval to capture the temporal (seasonal and short-term) and spatial variations of δD for one year of measurement at two dedicated sites (Darwin and Izan∼a) and a latitudinal band from g-60° to 60° for a 15 day period in January. We report a generally good agreement between IASI and the model and indicate the capabilities of IASI to reproduce the large scale variations of δD (seasonal cycle and latitudinal gradient) with good accuracy. In particular, we show that there is no systematic significant bias in the retrieved δD values in comparison with the model, and that the retrieved variability is similar to the one in the model even though there are certain local differences. Moreover, the noticeable differences between IASI and the model are briefly examined and suggest modeling issues instead of retrieval effects. Finally, the results further reveal the unprecedented capabilities of IASI to capture short-term variations in δD, highlighting the added value of the sounder for monitoring hydrological processes. © 2012 Author(s).
BibTeX:
@article{Lacour2012,
  author = {Lacour, J.-L. and Risi, C. and Clarisse, L. and Bony, S. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {Mid-tropospheric δd observations from IASI/MetOp at high spatial and temporal resolution},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {10817-10832},
  doi = {10.5194/acp-12-10817-2012}
}
Abstract: Accurate ab initio intermolecular potential energy surfaces (IPES) have been obtained for the first time for the ground electronic state of the C 2H2-Kr and C2H2-Xe van der Waals complexes. Extensive tests, including complete basis set and all-electron scalar relativistic results, support their calculation at the CCSD(T) level of theory, using small-core relativistic pseudopotentials for the rare-gas atoms and aug-cc-pVQZ basis sets extended with a set of 3s3p2d1f1g mid-bond functions. All results are corrected for the basis set superposition error. The importance of the scalar relativistic and rare-gas outer-core (n.1)d correlation effects is investigated. The calculated IPES, adjusted to analytical functions, are characterized by global minima corresponding to skew T-shaped geometries, in which the Jacobi vector positioning the rare-gas atom with respect to the center of mass of the C2H2 moiety corresponds to distances of 4.064 and 4.229Å, and angles of 65.22° and 68.67° for C 2H2-Kr and C2H2-Xe, respectively. The interaction energy of both complexes is estimated to be -151.88 (1.817 kJ mol-1) and -182.76 cm-1 (2.186 kJ mol-1), respectively. The evolution of the topology of the IPES as a function of the rare-gas atom, from He to Xe, is also discussed. © 2012 Taylor and Francis.
BibTeX:
@article{Lauzin2012,
  author = {Lauzin, C. and Cauët, E. and Demaison, J. and Herman, M. and Stoll, H. and Liévina, J.},
  title = {Accurate ground-state potential energy surfaces of the C2H 2-Kr and C2H2-Xe van der Waals complexes},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2751-2760},
  doi = {10.1080/00268976.2012.713524}
}
Abstract: In the framework of the multiconfiguration Dirac-Hartree-Fock method, we investigate the transition properties of four excited states in the 2p53s configuration of neutral neon. The electron correlation effects are taken into account systematically by using the active space approach. The effect of higher-order correlation on fine structures is shown. We also study the influence of the Breit interaction and find that it reduces the oscillator strength of the 3P1o-1S0 transition by 17%. It turns out that the inclusion of the Breit interaction is essential even for such a light atomic system. Our ab initio calculated line strengths, oscillator strengths, and transition rates are compared with other theoretical values and experimental measurements. Good agreement is found except for the 3P2o-1S0 M2 transition for which discrepancies of around 15% between theories and experiments remain. In addition, the impact of hyperfine interactions on the lifetimes of the 3P0o and 3P2o metastable states is investigated for the 21Ne isotope (I=3/2). We find that hyperfine interactions reduce the lifetimes drastically. For the 3P0o state the lifetime is decreased by a factor of 630. © 2012 American Physical Society.
BibTeX:
@article{Li2012b,
  author = {Li, J. and Jönsson, P. and Godefroid, M. and Dong, C. and Gaigalas, G.},
  title = {Effects of the electron correlation and Breit and hyperfine interactions on the lifetime of the 2p53s states in neutral neon},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2012},
  volume = {86},
  article number = {052523},
  doi = {10.1103/PhysRevA.86.052523}
}
Abstract: It was recently shown that dielectronic recombination measurements can be used for accurately inferring changes in the nuclear mean-square charge radii of highly charged lithiumlike neodymium. To make use of this method to derive information about the nuclear charge distribution for other elements and isotopes, accurate electronic isotope shift parameters are required. In this work, we calculate and discuss the relativistic mass- and field-shift factors for the two 2s2S 1/2-2p2P1/2,3/2o transitions along the lithium isoelectronic sequence. Based on the multiconfiguration Dirac-Hartree-Fock method, the electron correlation and the Breit interaction are taken into account systematically. The analysis of the isotope shifts for these two transitions along the isoelectronic sequence demonstrates the importance and competition between the mass shifts and the field shifts. © 2012 American Physical Society.
BibTeX:
@article{Li2012,
  author = {Li, J. and Nazé, C. and Godefroid, M. and Fritzsche, S. and Gaigalas, G. and Indelicato, P. and Jönsson, P.},
  title = {Mass- and field-shift isotope parameters for the 2s-2p resonance doublet of lithiumlike ions},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2012},
  volume = {86},
  article number = {022518},
  doi = {10.1103/PhysRevA.86.022518}
}
Abstract: The Dirac kinetic energy (DKE) form of the normal mass shift operator (me/M ∑i=1 N Ti), which is an approximation of the (1/2M ∑i=1 N pi 2) operator built on the relativistic electron momenta, is widely used in relativistic atomic structure calculations. In the present paper, we illustrate the progressive breakdown of the Dirac kinetic energy form relatively to the momentum form when increasing the nuclear charge along the lithium isoelectronic sequence. Both forms are incorrect in the relativistic case but the DKE operator provides expectation values that are closer to the results obtained with the more complete relativistic recoil operator. © EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2012.
BibTeX:
@article{Li2012c,
  author = {Li, J.G. and Nazé, C. and Godefroid, M. and Gaigalas, G. and Jönsson, P.},
  title = {On the breakdown of the Dirac kinetic energy operator for estimating normal mass shifts},
  journal = {European Physical Journal D},
  year = {2012},
  volume = {66},
  article number = {290},
  doi = {10.1140/epjd/e2012-30328-5}
}
Abstract: Large-scale calculations have been performed using the GRASP2K package to accurately determine the lifetime of levels in 2p53s configuration of neutral neon. In particular, we calculated the hyperfine-induced transition rates from two metastable levels 3P20,0 to the ground state for odd Ne isotopes. It was found that hyperfine interactions drastically quench the lifetime of these two levels.
BibTeX:
@article{Li2012a,
  author = {Li, J.G. and Verdebout, S. and Godefroid, M.},
  title = {Ab-initio multi-configuration Dirac-Hartree-Fock calculation on the lifetimes of levels in 2p53s configuration of neutral neon},
  journal = {Journal of Physics: Conference Series},
  year = {2012},
  volume = {388},
  article number = {152007},
  doi = {10.1088/1742-6596/388/15/152007}
}
Abstract: We present a quantal study of the rotationally elastic and inelastic scattering of Ag and N 2, with the nitrogen molecule treated as a rigid rotor. The two-dimensional potential energy surface of the AgN 2 complex is obtained ab initio by means of the spin unrestricted coupled-cluster method with single, double, and perturbative triple excitations. The global minimum is found to be located at an internuclear distance of 8.13 a 0 and an angle of 127.2. The long-range part of the potential is constructed from the dynamic electric dipole polarizabilities of Ag and N 2. Elastic, excitation, and relaxation cross sections and rates are calculated for energies between 0.1 and 5000 cm -1. The momentum transfer cross sections and rates are also computed. Finally, we compare the cross sections for Ag-N 2 and Na-N 2 to explore the possibility of using silver instead of sodium in experimental tests. © 2012 American Institute of Physics.
BibTeX:
@article{Loreau2012,
  author = {Loreau, J. and Zhang, P. and Dalgarno, A.},
  title = {Scattering of nitrogen molecules by silver atoms},
  journal = {Journal of Chemical Physics},
  year = {2012},
  volume = {136},
  article number = {164305},
  doi = {10.1063/1.3703518}
}
Abstract: Volcanic degassing produces abundant H2O and CO2, as well as SO2, HCl, H2S, S2, H2, HF, CO, and SiF4. Volcanic SO2, HCl, and H2S have been detected from satellites in the past; the remaining species are analyzed in situ or using airborne instruments, with all the consequent limitations in safety and sampling, and at elevated costs. We report identification of high CO concentrations consistent with a volcanic origin (the 2010 Eyjafjallajkull and 2011 Grímsvtn eruptions in Iceland) in data from the Measurements of Pollution in the Troposphere instrument (MOPITT) onboard EOS/Terra. The high CO values coincide spatially and temporally with ash plumes emanating from the eruptive centers, with elevated SO2 and aerosol optical thickness, as well as with high CO values in data from the Infrared Atmospheric Sounding Interferometer (IASI), onboard MetOp-A. CO has a positive indirect radiative forcing; climate models currently do not account for volcanic CO emissions. Given global volcanic CO2 emissions between 130 and 440 Tg/year and volcanic CO:CO2 ratios from the literature, we estimate that average global volcanic CO emissions may be on the order of ∼5.5 Tg/year, equivalent to the CO emissions caused by combined fossil fuel and biofuel combustion in Australia. © 2012. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Martinez-Alonso2012,
  author = {Martínez-Alonso, S. and Deeter, M.N. and Worden, H.M. and Clerbaux, C. and Mao, D. and Gille, J.C.},
  title = {First satellite identification of volcanic carbon monoxide},
  journal = {Geophysical Research Letters},
  year = {2012},
  volume = {39},
  article number = {L21809},
  doi = {10.1029/2012GL053275}
}
Abstract: When the effects of the finite mass of the nucleus and the spatial nuclear charge distribution are taken into account in the Hamiltonian describing an atomic system, the isotopes of an element have different electronic energy levels. In the present work, we are investigating these mass and field effects in neutral barium, hoping to shed some light on the surprising observed deviation of isotope shifts from their expected behavior for odd isotopes in an analysis based on King-plots.
BibTeX:
@article{Naze2012,
  author = {Nazé, C. and Li, J.G. and Godefroid, M.},
  title = {Relativistic calculations on isotope shifts in barium},
  journal = {Journal of Physics: Conference Series},
  year = {2012},
  volume = {388},
  article number = {152008},
  doi = {10.1088/1742-6596/388/15/152008}
}
Abstract: This study analyzes relationships between concentration of suspended particles represented by dry mass, [SPM], or area, [AC], and optical properties including particulate beam attenuation (cp), side scattering (bs), and backscattering (bbp), obtained from an intensive sampling program in coastal and offshore waters around Europe and French Guyana. First-order optical properties are driven by particle concentration with best predictions of [SPM] by bbp and bs, and of [AC] by cp. Second-order variability is investigated with respect to particle size, apparent density (dry weight-to-wet-volume ratio), and composition. Overall, the mass-specific particulate backscattering coefficient, bmp (=bbp: [SPM]), is relatively well constrained, with variability of a factor of 3-4. This coefficient is well correlated with particle composition, with inorganic particles having values about three times greater (brmp= 0.012 m2 g_1) than organic particles (brmp= 0.005 m2 g_1). The mass-specific particulate attenuation coefficient, cm (= cp: [SPM]), on the other hand, varies over one order of magnitude and is strongly driven (77% of the variability explained) by particle apparent density. In this data set particle size does not affect cm and affects b b m p only weakly in clear (case 1) waters, despite size variations over one order of magnitude. A significant fraction (40-60%) of the variability in bmp remains unexplained. Possible causes are the limitation of the measured size distributions to the 2-302-mm range and effects of particle shape and internal structure that affect bbp more than cp and were not accounted for. © 2012, by the Association for the Sciences of Limnology and Oceanography, Inc.
BibTeX:
@article{Nekermans2012,
  author = {Nekermans, G. and Loisel, H. and Meriaux, X. and Astoreca, R. and McKee, D.},
  title = {In situ variability of mass-specific beam attenuation and backscattering of marine particles with respect to particle size, density, and composition},
  journal = {Limnology and Oceanography},
  year = {2012},
  volume = {57},
  pages = {124-144},
  doi = {10.4319/lo.2011.57.1.0124}
}
Abstract: An extensive set of airborne and satellite observations of volcanic ash from the Eyjafjallajökull Icelandic eruption are analyzed for a case study on 17 May 2010. Data collected from particle scattering probes and backscatter lidar on the Facility for Airborne Atmospheric Measurements (FAAM) BAe 146 aircraft allow estimates of ash concentration to be derived. Using radiative transfer simulations we show that airborne and satellite infrared radiances can be accurately modeled based on the in situ measured size distribution and a mineral dust refractive index. Furthermore, airborne irradiance measurements in the 0.3-1.7 m range are well modeled with these properties. Retrievals of ash mass column loading using Infrared Atmospheric Sounding Interferometer (IASI) observations are shown to be in accord with lidar-derived mass estimates, giving for the first time an independent verification of a hyperspectral ash variational retrieval method. The agreement of the observed and modeled solar and terrestrial irradiances suggests a reasonable degree of radiative closure implying that the physical and optical properties of volcanic ash can be relatively well constrained using data from state-of-the-science airborne platforms such as the FAAM BAe 146 aircraft. Comparisons with IASI measurements during recent Grímsvötn and Puyehue volcanic eruptions demonstrate the importance of accurately specifying the refractive index when modeling the observed spectra.
BibTeX:
@article{Newman2012,
  author = {Newman, S.M. and Clarisse, L. and Hurtmans, D. and Marenco, F. and Johnson, B. and Turnbull, K. and Havemann, S. and Baran, A.J. and O'Sullivan, D. and Haywood, J.},
  title = {A case study of observations of volcanic ash from the Eyjafjallajökull eruption: 2. Airborne and satellite radiative measurements},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2012},
  volume = {117},
  article number = {D00U13},
  doi = {10.1029/2011JD016780}
}
Abstract: We have analysed the sensitivity of the tropospheric ozone distribution over North America and the North Atlantic to boreal biomass burning emissions during the summer of 2010 using the GEOS-Chem 3-D global tropospheric chemical transport model and observations from in situ and satellite instruments. We show that the model ozone distribution is consistent with observations from the Pico Mountain Observatory in the Azores, ozonesondes across Canada, and the Tropospheric Emission Spectrometer (TES) and Infrared Atmospheric Sounding Instrument (IASI) satellite instruments. Mean biases between the model and observed ozone mixing ratio in the free troposphere were less than 10 ppbv. We used the adjoint of GEOS-Chem to show the model ozone distribution in the free troposphere over Maritime Canada is largely sensitive to NOx emissions from biomass burning sources in Central Canada, lightning sources in the central US, and anthropogenic sources in the eastern US and south-eastern Canada. We also used the adjoint of GEOS-Chem to evaluate the Fire Locating And Monitoring of Burning Emissions (FLAMBE) inventory through assimilation of CO observations from the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument. The CO inversion showed that, on average, the FLAMBE emissions needed to be reduced to 89% of their original values, with scaling factors ranging from 12% to 102%, to fit the MOPITT observations in the boreal regions. Applying the CO scaling factors to all species emitted from boreal biomass burning sources led to a decrease of the model tropospheric distributions of CO, PAN, and NOx by as much as -20 ppbv, -50 pptv, and -20 pptv respectively. The modification of the biomass burning emission estimates reduced the model ozone distribution by approximately -3 ppbv (-8%) and on average improved the agreement of the model ozone distribution compared to the observations throughout the free troposphere, reducing the mean model bias from 5.5 to 4.0 ppbv for the Pico Mountain Observatory, 3.0 to 0.9 ppbv for ozonesondes, 2.0 to 0.9 ppbv for TES, and 2.8 to 1.4 ppbv for IASI. © 2012 Author(s).
BibTeX:
@article{Parrington2012,
  author = {Parrington, M. and Palmer, P.I. and Henze, D.K. and Tarasick, D.W. and Hyer, E.J. and Owen, R.C. and Helmig, D. and Clerbaux, C. and Bowman, K.W. and Deeter, M.N. and Barratt, E.M. and Coheur, P.-F. and Hurtmans, D. and Jiang, Z. and George, M. and Worden, J.R.},
  title = {The influence of boreal biomass burning emissions on the distribution of tropospheric ozone over North America and the North Atlantic during 2010},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {2077-2098},
  doi = {10.5194/acp-12-2077-2012}
}
Abstract: The vibration-rotation dynamics of X̃1Σ +g acetylene are computed from a spectroscopic Hamiltonian with 468 parameters fit to 19,582 vibration-rotation transitions up to 13,000 cm-1 of vibrational energy. In this energy range, both the bending and the CH stretching vibrations can reach large amplitudes, but the maximum energy remains below the threshold for isomerization to vinylidene. In contrast to the behavior at energies below 5000 cm-1 [Mol. Phys. 108, 1115 (2010)], excitation of single bright states leads, in almost all cases, to computed intramolecular vibrational redistribution (IVR) that is irreversible on the timescales investigated. Hierarchies of IVR processes on timescales ranging from 20 fs to 20 ps result when different bright states are excited. Different parts of the vibrational quantum number space are explored as a result of the four different classes of coupling terms: vibrational l-type resonance, anharmonic resonances, the rotational l-type resonance, and Coriolis couplings. The initial IVR rates are very different depending on whether the bright states are bending states or stretching states, normal modes or local modes, edge states or interior states. However, the rates of the rotationally mediated couplings do not depend substantially on these distinctions. © 2012 Taylor and Francis.
BibTeX:
@article{Perry2012,
  author = {Perry, D.S. and Martens, J. and Amyay, B. and Herman, M.},
  title = {Hierarchies of intramolecular vibration-rotation dynamical processes in acetylene up to 13,000 cm-1},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2687-2705},
  doi = {10.1080/00268976.2012.711493}
}
Abstract: Ozone data retrieved in the Arctic region from infrared radiance spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI) on board the MetOp-A European satellite are presented. They are compared with in situ and lidar observations obtained during a series of aircraft measurement campaigns as part of the International Polar Year POLARCAT activities in spring and summer 2008. Different air masses were sampled during the campaigns including clean air, polluted plumes originating from anthropogenic sources, forest fire plumes from the three northern continents, and stratospheric-influenced air masses. The comparison between IASI O 3 [0-8 km], [0-12 km] partial columns and profiles with collocated aircraft observations is achieved by taking into account the different sensitivity and geometry of the sounding instruments. A detailed analysis is provided and the agreement is discussed in terms of vertical sensitivity and surface properties at the location of the observations. Overall, IASI O3 profiles are found to be in relatively good agreement with smoothed in situ and lidar profiles in the free troposphere with differences of less than 40% (25% over sea for both seasons) and 10%, respectively. The correlation between IASI O 3 retrieved partial columns and the smoothed aircraft partial columns is good with DC-8 in situ data in spring over North America (r= Combining double low line 0.68), and over Greenland with ATR-42 lidar measurements in summer (r= Combining double low line 0.67). Correlations with other data are less significant highlighting the difficulty of IASI to capture precisely the O 3 variability in the Arctic upper troposphere and lower stratosphere (UTLS). This is particularly noted in comparison with the [0-12 km] partial columns. The IASI [0-8 km] partial columns display a low negative bias (by less than 26% over snow) compared to columns derived from in situ measurements. Despite the relatively high biases of the IASI retrievals in the Arctic UTLS, our analysis shows that IASI can be used to identify, using O 3/CO ratios, stratospheric intrusions. © 2012 Author(s).
BibTeX:
@article{Pommier2012,
  author = {Pommier, M. and Clerbaux, C. and Law, K.S. and Ancellet, G. and Bernath, P. and Coheur, P.-F. and Hadji-Lazaro, J. and Hurtmans, D. and Nédélec, P. and Paris, J.-D. and Ravetta, F. and Ryerson, T.B. and Schlager, H. and Weinheimer, A.J.},
  title = {Analysis of IASI tropospheric O3 data over the Arctic during POLARCAT campaigns in 2008},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  doi = {10.5194/acp-12-7371-2012}
}
Abstract: In this study we have retrieved the self-broadened widths, self-pressure-induced shifts, and Dicke narrowing coefficients for 20 R-branch transitions in the v1+v2+v4+v5 band of acetylene. The spectra were recorded using a three-channel diode laser spectrometer, a temperature-controlled cell of fixed length and a second, room temperature cell. The soft collision (Galatry) and hard collision (Rautian) profiles with inclusion of line mixing effects were used to retrieve the line parameters. We determined the temperature dependencies for line broadening, shift, and Dicke narrowing coefficients. We performed comparisons between our retrieved line parameters and published line parameters for acetylene transitions. © 2012 Taylor and Francis.
BibTeX:
@article{Povey2012,
  author = {Povey, C. and Predoi-Cross, A. and Hurtmans, D.R.},
  title = {Low-pressure line shape study of acetylene transitions in the v1 + v2 + v4 + v5 band over a range of temperatures},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2633-2644},
  doi = {10.1080/00268976.2012.705908}
}
Abstract: The far infrared spectrum of HCOOH was recorded at a high resolution (0.0009cm -1) and long path length (72m) at the far-infrared beamline, Canadian Light Source. Spectra were recorded in the region 62-300cm -1, showing transitions from the trans-isomer.Ground state rotational transitions with K a up to 30, were identified up to 175cm -1, extending the observation reported in the literature. A total of 3321 transitions were assigned and fitted together with previous (4149) published data. An improved set of rotational parameters was obtained adopting the symmetric top (A) reduction of the rotational Hamiltonian in the I r representation. The newly measured far infrared transitions allowed the determination of all diagonal and off diagonal 8th order parameters L and of some of the diagonal 10th order parameters P. © 2012 Elsevier Ltd.
BibTeX:
@article{Predoi-Cross2012,
  author = {Predoi-Cross, A. and Herman, M. and Fusina, L. and Di Lonardo, G.},
  title = {The far infrared spectrum of trans-formic acid: An extension up to 175cm -1},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2012},
  volume = {113},
  pages = {1134-1137},
  doi = {10.1016/j.jqsrt.2012.01.026}
}
Abstract: The vibration-rotation spectra of 13C substituted acetylene, 13C2H2, have been recorded in the region between 60 and 2600 cm-1 at an effective resolution ranging from 0.001 to 0.006 cm-1. Three different instruments were used to collect the experimental data in the extended spectral interval investigated. In total 9529 rotation vibration transitions have been assigned to 101 bands involving the bending states up to vtot=v4=v-1=4, allowing the characterization of the ground state and of 33 vibrationally excited states. All the bands involving states up to vtot=3 have been analyzed simultaneously by adopting a model Hamiltonian which takes into account the vibration and rotation l-type resonances. The derived spectroscopic parameters reproduce the transition wavenumbers with a RMS value of the order of the experimental uncertainty. Using the same model, larger discrepancies between observed and calculated values have been obtained for transitions involving states with vtot=4. These could be satisfactorily reproduced only by adopting a set of effective constants for each vibrational manifold, in addition to the previously determined parameters, which were constrained in the analysis. © 2012 Taylor and Francis.
BibTeX:
@article{Predoi-Cross2012a,
  author = {Predoi-Cross, A. and Herman, M. and Fusina, L. and Di Lonardo, G.},
  title = {The infrared spectrum of 13C2H2 in the 60-2600 cm-1 region: Bending states up to v4+v 5=4},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2621-2632},
  doi = {10.1080/00268976.2012.705345}
}
Abstract: N2-broadened line widths and N2-pressure induced line shifts have been measured for transitions in the v1+v3 band of acetylene at seven temperatures in the range 213-333K to obtain the temperature dependences of broadening and shift coefficients. For the room-temperature spectra the line mixing effects have been also investigated. The Voigt and hard-collision line profile models were used to retrieve the line parameters. All spectra were recorded using a 3-channel tuneable diode laser spectrometer. The line-broadening and line-shifting coefficients as well as their temperature-dependence parameters have been also evaluated theoretically, in the frame of a semi-classical approach based on an exponential representation of the scattering operator, an intermolecular potential composed of electrostatic quadrupole-quadrupole and pairwise atom-atom interactions as well as on exact trajectories driven by an effective isotropic potential. © 2012 Taylor and Francis.
BibTeX:
@article{Rozario2012,
  author = {Rozario, H. and Garber, J. and Povey, C. and Hurtmans, D. and Buldyreva, J. and Predoi-Cross, A.},
  title = {Experimental and theoretical study of N2-broadened acetylene line parameters in the v1+v3 band over a range of temperatures},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2645-2663},
  doi = {10.1080/00268976.2012.720040}
}
Abstract: Following our recent study devoted to measurements of intensities of pure rotation lines of methane, room temperature far infrared spectra of methane diluted in nitrogen at five total pressures between 100 and 800hPa have been recorded at the AILES beamline of the SOLEIL synchrotron. One hundred and five N 2 broadening coefficients of methane pure rotation lines have been measured in the 83-261cm -1 spectral range using multi-spectrum non-linear least squares fitting of Voigt profiles. Pressure-induced line shifts were not needed to fit the spectra to the noise level and line mixing effects were neglected. One hundred and seventy-six self broadening coefficients have also been measured in the 59-288cm -1 spectral range using the pure methane spectra recorded in our previous work. The measured N 2 broadening coefficients were compared to semi-classical calculations. © 2012 Elsevier Ltd.
BibTeX:
@article{Sanzharov2012,
  author = {Sanzharov, M. and Vander Auwera, J. and Pirali, O. and Roy, P. and Brubach, J.-B. and Manceron, L. and Gabard, T. and Boudon, V.},
  title = {Self and N 2 collisional broadening of far-infrared methane lines measured at the SOLEIL synchrotron},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2012},
  volume = {113},
  pages = {1874-1886},
  doi = {10.1016/j.jqsrt.2012.06.001}
}
Abstract: Measurements of ozone vertical profiles are valuable for the evaluation of atmospheric chemistry models and contribute to the understanding of the processes controlling the distribution of tropospheric ozone. The longest record of ozone vertical profiles is provided by ozone sondes, which have a typical frequency of 4 to 12 profiles a month. Here we quantify the uncertainty introduced by low frequency sampling in the determination of means and trends. To do this, the high frequency MOZAIC (Measurements of OZone, water vapor, carbon monoxide and nitrogen oxides by in-service AIrbus airCraft) profiles over airports, such as Frankfurt, have been subsampled at two typical ozone sonde frequencies of 4 and 12 profiles per month. We found the lowest sampling uncertainty on seasonal means at 700 hPa over Frankfurt, with around 5% for a frequency of 12 profiles per month and 10% for a 4 profile-a-month frequency. However the uncertainty can reach up to 15 and 29% at the lowest altitude levels. As a consequence, the sampling uncertainty at the lowest frequency could be higher than the typical 10% accuracy of the ozone sondes and should be carefully considered for observation comparison and model evaluation. We found that the 95% confidence limit on the seasonal mean derived from the subsample created is similar to the sampling uncertainty and suggest to use it as an estimate of the sampling uncertainty. Similar results are found at six other Northern Hemisphere sites. We show that the sampling substantially impacts on the inter-annual variability and the trend derived over the period 1998-2008 both in magnitude and in sign throughout the troposphere. Also, a tropical case is discussed using the MOZAIC profiles taken over Windhoek, Namibia between 2005 and 2008. For this site, we found that the sampling uncertainty in the free troposphere is around 8 and 12% at 12 and 4 profiles a month respectively. © 2012 Author(s).
BibTeX:
@article{Saunois2012,
  author = {Saunois, M. and Emmons, L. and Lamarque, J.-F. and Tilmes, S. and Wespes, C. and Thouret, V. and Schultz, M.},
  title = {Impact of sampling frequency in the analysis of tropospheric ozone observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {6757-6773},
  doi = {10.5194/acp-12-6757-2012}
}
Abstract: In this paper we present a study of the ozone hole as observed by the Infrared Atmospheric Sounding Interferometer (IASI) on-board the MetOp-A European satellite platform from the beginning of data dissemination, August 2008, to the end of December 2010. Here we demonstrate IASI's ability to capture the seasonal characteristics of the ozone hole, in particular during polar night. We compare IASI ozone total columns and vertical profiles with those of the Global Ozone Monitoring Experiment 2 (GOME-2, also on-board MetOp-A) and electrochemical concentration cell (ECC) ozone sonde measurements. Total ozone column from IASI and GOME-2 were found to be in excellent agreement for this region with a correlation coefficient of 0.97, for September, October and November 2009. On average IASI exhibits a positive bias of approximately 7% compared to the GOME-2 measurements over the entire ozone hole period. Comparisons between IASI and ozone sonde measurements were also found to be in good agreement with the difference between both ozone profile measurements being less than ±30% over the altitude range of 0-40 km. The vertical structure of the ozone profile inside the ozone hole is captured remarkably well by IASI. © Author(s) 2012.
BibTeX:
@article{Scannell2012,
  author = {Scannell, C. and Hurtmans, D. and Boynard, A. and Hadji-Lazaro, J. and George, M. and Delcloo, A. and Tuinder, O. and Coheur, P.-F. and Clerbaux, C.},
  title = {Antarctic ozone hole as observed by IASI/MetOp for 2008-2010},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {123-139},
  doi = {10.5194/amt-5-123-2012}
}
Abstract: Formic acid contributes significantly to acid rain in remote environments. Direct sources of formic acid include human activities, biomass burning and plant leaves. Aside from these direct sources, sunlight-induced oxidation of non-methane hydrocarbons (largely of biogenic origin) is probably the largest source. However, model simulations substantially underpredict atmospheric formic acid levels, indicating that not all sources have been included in the models. Here, we use satellite measurements of formic acid concentrations to constrain model simulations of the global formic acid budget. According to our simulations, 100- 120Tg of formic acid is produced annually, which is two to three times more than that estimated from known sources. We show that 90% of the formic acid produced is biogenic in origin, and largely sourced from tropical and boreal forests. We suggest that terpenoids- volatile organic compounds released by plants- are the predominant precursors. Model comparisons with independent observations of formic acid strengthen our conclusions, and provide indirect validation for the satellite measurements. Finally, we show that the larger formic acid emissions have a substantial impact on rainwater acidity, especially over boreal forests in the summer, where formic acid reduces pH by 0.25- 0.5.
BibTeX:
@article{Stavrakou2012,
  author = {Stavrakou, T. and Müller, J.-F. and Peeters, J. and Razavi, A. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and De Mazière, M. and Vigouroux, C. and Deutscher, N.M. and Griffith, D.W.T. and Jones, N. and Paton-Walsh, C.},
  title = {Satellite evidence for a large source of formic acid from boreal and tropical forests},
  journal = {Nature Geoscience},
  year = {2012},
  volume = {5},
  pages = {26-30},
  doi = {10.1038/ngeo1354}
}
Abstract: Merapi volcano (Indonesia) is one of the most active and hazardous volcanoes in the world. It is known for frequent small to moderate eruptions, pyroclastic flows produced by lava dome collapse, and the large population settled on and around the flanks of the volcano that is at risk. Its usual behavior for the last decades abruptly changed in late October and early November 2010, when the volcano produced its largest and most explosive eruptions in more than a century, displacing at least a third of a million people, and claiming nearly 400 lives. Despite the challenges involved in forecasting this 'hundred year eruption', we show that the magnitude of precursory signals (seismicity, ground deformation, gas emissions) was proportional to the large size and intensity of the eruption. In addition and for the first time, near-real-time satellite radar imagery played an equal role with seismic, geodetic, and gas observations in monitoring eruptive activity during a major volcanic crisis. The Indonesian Center of Volcanology and Geological Hazard Mitigation (CVGHM) issued timely forecasts of the magnitude of the eruption phases, saving 10,000-20,000 lives. In addition to reporting on aspects of the crisis management, we report the first synthesis of scientific observations of the eruption. Our monitoring and petrologic data show that the 2010 eruption was fed by rapid ascent of magma from depths ranging from 5 to 30km. Magma reached the surface with variable gas content resulting in alternating explosive and rapid effusive eruptions, and released a total of  0.44Tg of SO2. The eruptive behavior seems also related to the seismicity along a tectonic fault more than 40km from the volcano, highlighting both the complex stress pattern of the Merapi region of Java and the role of magmatic pressurization in activating regional faults. We suggest a dynamic triggering of the main explosions on 3 and 4 November by the passing seismic waves generated by regional earthquakes on these days. © 2012 Elsevier B.V.
BibTeX:
@article{Surono2012,
  author = {Surono and Jousset, P. and Pallister, J. and Boichu, M. and Buongiorno, M.F. and Budisantoso, A. and Costa, F. and Andreastuti, S. and Prata, F. and Schneider, D. and Clarisse, L. and Humaida, H. and Sumarti, S. and Bignami, C. and Griswold, J. and Carn, S. and Oppenheimer, C. and Lavigne, F.},
  title = {The 2010 explosive eruption of Java's Merapi volcano-A '100-year' event},
  journal = {Journal of Volcanology and Geothermal Research},
  year = {2012},
  volume = {241-242},
  pages = {121-135},
  doi = {10.1016/j.jvolgeores.2012.06.018}
}
Abstract: When considering the work of Carl Ballhausen on vibrational spectra, it is suggested that his use of the Born-Oppenheimer approximation is capable of some refinement and extension in the light of later developments. A consideration of the potential energy surface in the context of a full Coulomb Schrödinger Hamiltonian in which translational and rotational motions are explicitly considered would seem to require a reformulation of the Born-Oppenheimer approach. The resulting potential surface for vibrational motion should be treated, allowing for the rotational motion and the nuclear permutational symmetry of the molecule. © 2011 Springer-Verlag Berlin Heidelberg.
BibTeX:
@article{Sutcliffe2012b,
  author = {Sutcliffe, B.T.},
  title = {Chemistry as a "manifestation of quantum phenomena" and the Born-Oppenheimer approximation?},
  journal = {Structure and Bonding},
  year = {2012},
  volume = {143},
  pages = {101-120},
  doi = {10.1007/430_2011_44}
}
Abstract: Transition state theory was introduced in the 1930s to account for chemical reactions. Central to this theory is the idea of a potential energy surface (PES). It was assumed that quantum mechanical computation, when it became possible, would yield such surfaces, but for the time being they would have to be constructed empirically. The approach was very successful. Nowadays, quantum mechanical ab initio electronic structure calculations are possible and from their results PESs can be constructed. Such surfaces are now widely used in the explanation of chemical reactions in place of the traditional empirical ones. It is argued here that theoretical basis of such PESs is not quite as clear as is usually assumed and that, from a quantum mechanical perspective, certain puzzles remain. © 2012 Springer-Verlag.
BibTeX:
@article{Sutcliffe2012a,
  author = {Sutcliffe, B.},
  title = {Is there an exact potential energy surface?},
  journal = {Theoretical Chemistry Accounts},
  year = {2012},
  volume = {131},
  pages = {1-11},
  doi = {10.1007/s00214-012-1215-x}
}
Abstract: The original account of the Born-Oppenheimer approximation is not mathematically secure because it is not legitimate to use perturbation theory in its development. It is necessary to use an asymptotic expansion based upon an electronic Hamiltonian defined in terms of a fiber bundle. Although with this approach it has been possible account for the traditional results for a diatomic molecule, rotational motion in the polyatomic case has not so far been accounted for. It is argued here that it is not generally possible to provide a mathematically secure account of the Born-Oppenheimer approximation for polyatomic molecules, in which rotation can be considered as a separable motion. © 2012 Wiley Periodicals, Inc. Copyright © 2012 Wiley Periodicals, Inc.
BibTeX:
@article{Sutcliffe2012c,
  author = {Sutcliffe, B.},
  title = {Some difficulties in considering rotation motion within the Born-Oppenheimer approximation for polyatomic molecules},
  journal = {International Journal of Quantum Chemistry},
  year = {2012},
  volume = {112},
  pages = {2894-2903},
  doi = {10.1002/qua.24021}
}
Abstract: This chapter starts by giving a brief account of the development of the atomic-molecular conception of chemistry. An essential backdrop to the whole discussion is the importance throughout human history of the practical chemical arts that have informed the production of the whole range of useful materials and stimulated enquiry into the theoretical aspects of chemical processes. Chemistry is concerned with the composition and properties of matter, and with the transformations of matter that can occur spontaneously or under the action of heat, radiation or other sources of energy. From the results of chemical experiments the chemist singles out a particular class of materials that have characteristic and invariant properties. Such materials are called pure substances and may be of two kinds, viz: compounds and elements. Elements may be defined as substances which have not been converted either by the action of heat, radiation, or chemical reaction with other substances, or small electrical voltages, into any simpler substance. Compounds are formed from the chemical combination of the elements, and have properties that are invariably different from the properties of the constituent elements; they are also homogeneous. This characteristic chemical notion of a pure substance is based on an ideal conception of the chemical and physical properties of matter and their changes under specified experimental conditions. © 2012 Elsevier B.V. All rights reserved.
BibTeX:
@book{Sutcliffe2012d,
  author = {Sutcliffe, B.T. and Guy Woolley, R.},
  title = {Atoms and molecules in classical chemistry and quantum mechanics},
  journal = {Philosophy of Chemistry},
  year = {2012},
  pages = {387-426},
  doi = {10.1016/B978-0-444-51675-6.50028-1}
}
Abstract: Transition state theory was introduced in 1930s to account for chemical reactions. Central to this theory is the idea of a potential energy surface (PES). It was assumed that such a surface could be constructed using eigensolutions of the Schrödinger equation for the molecular (Coulomb) Hamiltonian but at that time such calculations were not possible. Nowadays quantum mechanical ab initio electronic structure calculations are routine and from their results PESs can be constructed which are believed to approximate those assumed derivable from the eigensolutions. It is argued here that this belief is unfounded. It is suggested that the potential energy surface construction is more appropriately regarded as a legitimate and effective modification of quantum mechanics for chemical purposes. © 2012 American Institute of Physics.
BibTeX:
@article{Sutcliffe2012,
  author = {Sutcliffe, B.T. and Woolley, R.G.},
  title = {On the quantum theory of molecules},
  journal = {Journal of Chemical Physics},
  year = {2012},
  volume = {137},
  article number = {22A544},
  doi = {10.1063/1.4755287}
}
Abstract: The characterization and the precise measurements of atmospheric pollutant's concentration are essential to improve the understanding and modeling of urban air pollution processes. The QualAir platform at the Université Pierre et Marie Curie (UPMC) is an experimental research platform dedicated to urban air quality and pollution studies. As one of the major instruments, the ground-based QualAir Fourier transform spectrometer (FTS) provides information on the air composition of a megacity like Paris, France. Operating in solar infrared absorption, it enables the monitoring of several important pollutants involved in tropospheric chemistry and atmospheric transport around the Ile de France region. Results on nitrous oxide (N 2O), methane (CH 4), and carbon monoxide (CO) will be presented in this paper, as well as the CO measurements comparison with satellite and in situ measurements showing the capabilities and strengths of this groundbased FTS with the other instruments of the QualAir platform. © 2012 American Meteorological Society.
BibTeX:
@article{Te2012,
  author = {Té, Y.V. and Dieudonné, E. and Jeseck, P. and Hase, F. and Hadji-Lazaro, J. and Clerbaux, C. and Ravetta, F. and Payan, S. and Pépin, I. and Hurtmans, D. and Pelon, J. and Camy-Peyret, C.},
  title = {Carbon monoxide urban emission monitoring: A ground-based FTIR case study},
  journal = {Journal of Atmospheric and Oceanic Technology},
  year = {2012},
  volume = {29},
  pages = {911-921},
  doi = {10.1175/JTECH-D-11-00040.1}
}
Abstract: The Eyjafjallajökull ash that crossed over Spain and Portugal on 6-12 May 2010 has been monitored by a set of operational sun photometer sites within AERONET-RIMA and satellite sensors. The sun photometer observations (aerosol optical depth, coarse mode concentrations) and ash products from IASI and SEVIRI satellite sensors, together with FLEXPART simulations of particle transport, allow identifying the volcanic aerosols. The aerosol columnar properties derived from inversions were investigated, indicating specific properties, especially regarding the absorption. The single scattering albedo was high (0.95 at 440nm) and nearly wavelength independent, although with slight decrease with wavelength. Other parameters, like the fine mode fraction of the volume size distributions (0.20-0.80) or the portion of spherical particles (15-90%), were very variable among the sites and indicated that the various ash clouds were inhomogeneous with respect to particle size and shape. © 2011 Elsevier Ltd.
BibTeX:
@article{Toledano2012,
  author = {Toledano, C. and Bennouna, Y. and Cachorro, V. and Ortiz de Galisteo, J.P. and Stohl, A. and Stebel, K. and Kristiansen, N.I. and Olmo, F.J. and Lyamani, H. and Obregón, M.A. and Estellés, V. and Wagner, F. and Baldasano, J.M. and González-Castanedo, Y. and Clarisse, L. and de Frutos, A.M.},
  title = {Aerosol properties of the Eyjafjallajökull ash derived from sun photometer and satellite observations over the Iberian Peninsula},
  journal = {Atmospheric Environment},
  year = {2012},
  volume = {48},
  pages = {22-32},
  doi = {10.1016/j.atmosenv.2011.09.072}
}
Abstract: CO 2 broadened spectra of the 1-0 band of H 35Cl and H 37Cl, observed near 2886cm -1, and the 1-0 band of D 35Cl and D 37Cl, located near 2089cm -1, have been recorded at room temperature and five total pressures between 150 and 700Torr, using a Bruker IFS125HR Fourier transform spectrometer. Spectra of pure HCl were also recorded. CO 2 broadening and shift coefficients of HCl and DCl have been measured using multi-spectrum non-linear least squares fitting of Voigt profiles. The analysis of the 1-0 band of DCl was complicated by the presence of overlapping CO 2 bands, which were included in the treatment as absorption coefficients calculated taking line-mixing effects into account. © 2012 Elsevier Ltd.
BibTeX:
@article{Tudorie2012a,
  author = {Tudorie, M. and Földes, T. and Vandaele, A.C. and Vander Auwera, J.},
  title = {CO 2 pressure broadening and shift coefficients for the 1-0 band of HCl and DCl},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2012},
  volume = {113},
  pages = {1092-1101},
  doi = {10.1016/j.jqsrt.2012.01.025}
}
Abstract: The far infrared spectrum of cis-methyl formate has been recorded on the AILES beamline of the synchrotron SOLEIL using a Fourier transform infrared spectrometer coupled to a long path cell. The very weak fundamental band associated with the methyl-top torsion mode (ν 18) was observed. The frequency analysis was performed using the rho axis method, and the microwave and millimeter-wave data from the literature. A precise determination of the band origins (ν18A 132.4303 cm -1 and ν18E 131.8445 cm -1) and of the barrier height V 3 370.7398 (58) cm -1 have been obtained. The intensity of the ν 18 fundamental band was determined to be 3.4 × 10 -21 cm -1(molecule cm -2) at 297 K, equally shared among A-A and E-E transitions, thus leading to a dipole moment component μ c (3) equal to 0.0483 D. The results were compared with the ab initio calcula-tions of Senent [Astrophys. J. 627, 567 (2005)]10.1086/430201. © 2012 American Institute of Physics.
BibTeX:
@article{Tudorie2012,
  author = {Tudorie, M. and Ilyushin, V. and Auwera, J.V. and Pirali, O. and Roy, P. and Huet, T.R.},
  title = {Synchrotron FTIR spectroscopy of weak torsional bands: A case study of cis-methyl formate},
  journal = {Journal of Chemical Physics},
  year = {2012},
  volume = {137},
  article number = {064304},
  doi = {10.1063/1.4740250}
}
Abstract: We investigate the photodissociation process for both hot and cold HeH + ions. Detailed comparison with experiments performed at FLASH is made possible by experimentally determining the ro-vibrational distribution of the ions under identical source conditions, and averaging the theoretical cross sections accordingly. © Published under licence by IOP Publishing Ltd.
BibTeX:
@article{Urbain2012,
  author = {Urbain, X. and Lecointre, J. and Loreau, J. and Vaeck, N.},
  title = {Photodissociation from the ground state of HeH+: Comparison with experiment},
  journal = {Journal of Physics: Conference Series},
  year = {2012},
  volume = {388},
  article number = {022107},
  doi = {10.1088/1742-6596/388/2/022107}
}
Abstract: We present some progress associated to the localised correlation function interaction (LCFI) method. In this report, the LCFI method is tested not only for total energy but also for the specific mass shift operator, the hyperfine structure parameters and the transition probabilities. These properties are computed for the three lowest electronic states of the beryllium atom. These calculations illustrate the importance of the contraction effects.
BibTeX:
@article{Verdebout2012,
  author = {Verdebout, S. and Rynkun, P. and Jönsson, P. and Gaigalast, G. and Froese Fischer, C. and Godefroid, M.},
  title = {Interaction of variational localised correlation functions for atomic properties of Be I},
  journal = {Journal of Physics: Conference Series},
  year = {2012},
  volume = {388},
  article number = {152006},
  doi = {10.1088/1742-6596/388/15/152006}
}
Abstract: (3+1) resonantly enhanced multiphoton ionization (REMPI) spectroscopy coupled to photoelectron spectroscopy (REMPI-PES) has been carried out to study the Rydberg states of HC3N in the 77,000.90,000 cm-1 region. Ab initio calculations (energies and optimized equilibrium geometries) have been performed for the first time for the low-lying X̃2Π, Ã 2Σ+ and B̃2Π states of the cation HC3N+ in order to help the analysis. Thanks to the combination of the three-photon REMPI spectra, one-photon spectrum and photoelectron spectra, unambiguous assignments of the Rydberg series and their vibrationally excited members are proposed. The electronic Rydberg structure of cyanoacetylene is very similar to that of C2H2 and HCN (almost identical quantum defects), fully supporting the present analysis. New three-photon allowed Rydberg series are identified belonging to ns and nd series. The three-photon vibrational band assignments, confirmed by the photoelectrons spectra, reveal excitation of only one or two quanta of the v1 (C≅N) mode. Apparent discrepancies between the three-photon REMPI spectrum and the one-photon absorption spectrum are removed via a minor re-assignment of the absorption spectrum previously analysed by Connors et al. J. Chem. Phys. 60(12), 5011 (1974). Finally the observed analogy with C 2H2 and HCN can be rationalized by a partial relocalization of the 2π electrons upon excitation to Rydberg states converging to the X̃2Π state of HC3N+, as predicted by the present ab initio calculations on the cation core. © 2012 Taylor and Francis.
BibTeX:
@article{VieiraMendes2012,
  author = {Vieira Mendes, L.A. and Boyé-Péronne, S. and Jacovella, U. and Liévin, J. and Gauyacq, D.},
  title = {Rydberg states of cyanoacetylene investigated by (3+1) REMPI spectroscopy in the 77,000.90,000 cm-1 energy range},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2829-2842},
  doi = {10.1080/00268976.2012.706327}
}
Abstract: The absorption spectrum of propyne (CH 3CCH) has been investigated in the range 6200-6700 cm -1. Data were obtained using three different experimental techniques: conventional FTIR experiments (room temperature, 0.018 cm -1 resolution, 10 m absorption path), FTIR experiments using a femtosecond broadband absorption source and a build up cavity (room temperature, 0.02 cm -1 resolution, absorption path between 1500 and 12,000 m), cavity ring down spectroscopy to probe a propyne/Ar supersonic expansion (T rot ≈ 20 K, sub-Doppler resolution, 720 m effective absorption path length). The analysis focused on one perpendicular ( ν1+ν6±1) and four parallel (2ν 1, ν 1 + ν 2, ν 1 + ν 3 + ν 5, ν1+ ν3+2ν90) bands, all perturbed by a complex system of Coriolis and anharmonic interactions. A model Hamiltonian was built, including all symmetry allowed perturbations between the upper levels of the studied bands but not accounting for additional interacting states. In total 1176 rovibrational transitions have been assigned and simultaneously fitted (σ = 0.0029 cm -1), leading to a set of effective rovibrational parameters. The resulting polyad structure is discussed and additional bands identified in the spectral range are tentatively assigned. © 2012 Elsevier B.V. All rights reserved.
BibTeX:
@article{Villa2012,
  author = {Villa, M. and Fusina, L. and Nivellini, G. and Didriche, K. and De Ghellinck D'Elseghem Vaernewijck, X. and Herman, M.},
  title = {The infrared spectrum of propyne in the range 6200-6700 cm -1},
  journal = {Chemical Physics},
  year = {2012},
  volume = {402},
  pages = {14-21},
  doi = {10.1016/j.chemphys.2012.03.020}
}
Abstract: Although it is thought to play an important role in the chemistry of some extra-terrestrial environments, the HeH+ cation has not been detected in space so far. We suggest it could be observed in its triplets rather than singlet states and we study the formation by radiative stabiliation and the destruction by photodissociation of the two lowest states of this symmetry. © Published under licence by IOP Publishing Ltd.
BibTeX:
@article{Vranckx2012a,
  author = {Vranckx, S. and Loreau, J. and Desouter-Lecomte, M. and Vaeck, N.},
  title = {Radiative stabilization and photodissociation of HeH+ in its two lowest 3Σ+ states},
  journal = {Journal of Physics: Conference Series},
  year = {2012},
  volume = {388},
  article number = {022109},
  doi = {10.1088/1742-6596/388/2/022109}
}
Abstract: We implement a local control strategy based on the use of Moller operators and use it to control the photodissociation of diatomic molecules in the presence of nonadiabatic interactions.
BibTeX:
@article{Vranckx2012,
  author = {Vranckx, S. and Meier, C. and Bomble, L. and Chenel, A. and Desouter-Lecomte, M. and Vaeck, N.},
  title = {Local control of nonadiabatic photodissociation dynamics using Moller operators},
  journal = {Journal of Physics: Conference Series},
  year = {2012},
  volume = {388},
  article number = {112009},
  doi = {10.1088/1742-6596/388/11/112009}
}
Abstract: The hyperfine structure constants for the ground 4s24p 2P°3/2 and lowest excited states 4s25s 2S1/2 of 71Ga are calculated using the GRASP2K package based on the multi-configuration Dirac-Hartree-Fock method. Furthermore, the magnetic dipole (μ) and the electric quadrupole (Q) moments of the Ga isotopes from 67Ga to 81Ga are derived.
BibTeX:
@article{Wang2012,
  author = {Wang, Q.M. and Li, J.G. and Fritzsche, S. and Godefroid, M. and Chang, Z.W. and Dong, C.Z.},
  title = {Theoretical study of hyperfine structure constants of Ga isotopes},
  journal = {Journal of Physics: Conference Series},
  year = {2012},
  volume = {388},
  article number = {152009},
  doi = {10.1088/1742-6596/388/15/152009}
}
Abstract: Methanol retrievals from nadir-viewing space-based sensors offer powerful new information for quantifying methanol emissions on a global scale. Here we apply an ensemble of aircraft observations over North America to evaluate new methanol measurements from the Tropospheric Emission Spectrometer (TES) on the Aura satellite, and combine the TES data with observations from the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-A satellite to investigate the seasonality of methanol emissions from northern midlatitude ecosystems. Using the GEOS-Chem chemical transport model as an intercomparison platform, we find that the TES retrieval performs well when the degrees of freedom for signal (DOFS) are above 0.5, in which case the model:TES regressions are generally consistent with the model:aircraft comparisons. Including retrievals with DOFS below 0.5 degrades the comparisons, as these are excessively influenced by the a priori. The comparisons suggest DOFS >0.5 as a minimum threshold for interpreting retrievals of trace gases with a weak tropospheric signal. We analyze one full year of satellite observations and find that GEOS-Chem, driven with MEGANv2.1 biogenic emissions, underestimates observed methanol concentrations throughout the midlatitudes in springtime, with the timing of the seasonal peak in model emissions 1-2 months too late. We attribute this discrepancy to an underestimate of emissions from new leaves in MEGAN, and apply the satellite data to better quantify the seasonal change in methanol emissions for midlatitude ecosystems. The derived parameters (relative emission factors of 11.0, 0.26, 0.12 and 3.0 for new, growing, mature, and old leaves, respectively, plus a leaf area index activity factor of 0.5 for expanding canopies with leaf area index <1.2) provide a more realistic simulation of seasonal methanol concentrations in midlatitudes on the basis of both the IASI and TES measurements. © 2012 Author(s).
BibTeX:
@article{Wells2012,
  author = {Wells, K.C. and Millet, D.B. and Hu, L. and Cady-Pereira, K.E. and Xiao, Y. and Shephard, M.W. and Clerbaux, C.L. and Clarisse, L. and Coheur, P.-F. and Apel, E.C. and De Gouw, J. and Warneke, C. and Singh, H.B. and Goldstein, A.H. and Sive, B.C.},
  title = {Tropospheric methanol observations from space: Retrieval evaluation and constraints on the seasonality of biogenic emissions},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {5897-5912},
  doi = {10.5194/acp-12-5897-2012}
}
Abstract: In this paper, we analyze tropospheric O3 together with HNO 3 during the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) program, combining observations and model results. Aircraft observations from the NASA ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) and NOAA ARCPAC (Aerosol, Radiation and Cloud Processes affecting Arctic Climate) campaigns during spring and summer of 2008 are used together with the Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4) to assist in the interpretation of the observations in terms of the source attribution and transport of O 3 and HNO 3 into the Arctic (north of 60°N). The MOZART-4 simulations reproduce the aircraft observations generally well (within 15%), but some discrepancies in the model are identified and discussed. The observed correlation of O3 with HNO 3 is exploited to evaluate the MOZART-4 model performance for different air mass types (fresh plumes, free troposphere and stratospheric-contaminated air masses). Based on model simulations of O 3 and HNO 3 tagged by source type and region, we find that the anthropogenic pollution from the Northern Hemisphere is the dominant source of O 3 and HNO 3 in the Arctic at pressures greater than 400 hPa, and that the stratospheric influence is the principal contribution at pressures less 400 hPa. During the summer, intense Russian fire emissions contribute some amount to the tropospheric columns of both gases over the American sector of the Arctic. North American fire emissions (California and Canada) also show an important impact on tropospheric ozone in the Arctic boundary layer. Additional analysis of tropospheric O 3 measurements from ground-based FTIR and from the IASI satellite sounder made at the Eureka (Canada) and Thule (Greenland) polar sites during POLARCAT has been performed using the tagged contributions. It demonstrates the capability of these instruments for observing pollution at northern high latitudes. Differences between contributions from the sources to the tropospheric columns as measured by FTIR and IASI are discussed in terms of vertical sensitivity associated with these instruments. The first analysis of O 3 tropospheric columns observed by the IASI satellite instrument over the Arctic is also provided. Despite its limited vertical sensitivity in the lowermost atmospheric layers, we demonstrate that IASI is capable of detecting low-altitude pollution transported into the Arctic with some limitations. © 2012 Author(s).
BibTeX:
@article{Wespes2012,
  author = {Wespes, C. and Emmons, L. and Edwards, D.P. and Hannigan, J. and Hurtmans, D. and Saunois, M. and Coheur, P.-F. and Clerbaux, C. and Coffey, M.T. and Batchelor, R.L. and Lindenmaier, R. and Strong, K. and Weinheimer, A.J. and Nowak, J.B. and Ryerson, T.B. and Crounse, J.D. and Wennberg, P.O.},
  title = {Analysis of ozone and nitric acid in spring and summer Arctic pollution using aircraft, ground-based, satellite observations and MOZART-4 model: Source attribution and partitioning},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {237-259},
  doi = {10.5194/acp-12-237-2012}
}
Abstract: The radiative properties of the W 5 + ion are investigated using two independent theoretical approaches, i.e. the HartreeFock method with relativistic corrections of Cowan and the multiconfiguration DiracHartreeFock method as implemented in the grasp2k package. The corevalence correlations are studied in detail comparing models where a core-polarization model potential plus a correction to the dipole operator are considered (HFR + CPOL) on the one hand, and core-excited configurations are explicitly included in the configuration-interaction expansion of the atomic state function on the other hand. In general, a good agreement is found between the two theoretical methods. Core-polarization effects are remarkably strong lengthening the lifetimes up to 15%35% and even by a factor of 2 for the 5f levels. The lifetimes of the two 5f levels are found to be model dependent and particularly sensitive to core-penetration effects; precise measurements are clearly needed here. © 2012 IOP Publishing Ltd.
BibTeX:
@article{Yoca2012,
  author = {Yoca, S.E. and Palmeri, P. and Quinet, P. and Jumet, G. and Biémont, E.},
  title = {Radiative properties and core-polarization effects in the W 5+ ion},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2012},
  volume = {45},
  article number = {035002},
  doi = {10.1088/0953-4075/45/3/035002}
}
Abstract: The internal partition function (Q int) of ethyne (acetylene), 12C 2H 2, is calculated by explicit summation of the contribution of all individual vibration-rotation energy levels up to 15 000 cm -1. The corresponding energies are predicted from a global model and constants reproducing within 3σ all 18 415 published vibration-rotation lines in the literature involving vibrational states up to 8900 cm -1, as produced by Amyay J. Mol. Spectrosc. 267, 80 (2011). Values of Q int, with distinct calculations for para and ortho species are provided from 1 to 2000 K, in step of 1 K. The total internal partition function at 298.15 K is 104.224387(47) or 416.89755(19), with the nuclear degeneracy spin factors taken as 1/4: 3/4 (astronomer convention) or 1:3 (atmospheric convention), respectively, for para:ortho species. The Helmholtz function, Gibbs enthalpy function, entropy, and specific heat at constant pressure are also calculated over the same temperature range. Accuracies as well as the missing contribution of the vinylidene isomer of acetylene in the calculations are discussed. © 2011 American Institute of Physics.
BibTeX:
@article{Amyay2011,
  author = {Amyay, B. and Fayt, A. and Herman, M.},
  title = {Accurate partition function for acetylene, 12C 2H 2, and related thermodynamical quantities},
  journal = {Journal of Chemical Physics},
  year = {2011},
  volume = {135},
  article number = {234305},
  doi = {10.1063/1.3664626}
}
Abstract: The analysis of CW-cavity ring down absorption spectra of 12C2H2 previously reported by Robert et al. (Mol. Phys. 106 (2008) 2581) was improved in the range 6667-7015 cm -1. Some 1825 lines were newly assigned. They either belong to 105 new sub-bands, involving 69 previously unreported sub-states, or extend assignments in 35 already known sub-bands. A global fit procedure of line positions from the full 12C2H2 database containing 18 415 lines, including those newly assigned, was performed, accessing vibrational states up to 8900 cm-1. Coriolis interactions were systematically introduced in the global Hamiltonian, which also accounted for higher order vibrational constants and considered the role of higher excited bending states than before. The dimensionless standard deviation of the fit was 1.07 and 396 effective vibration-rotation parameters were determined. Two local, interpolyad couplings were evidenced for the first time. A set of 121 new lines from 12CH13CH present in natural abundance in the gas sample were also assigned. © 2011 Elsevier Inc. All rights reserved.
BibTeX:
@article{Amyay2011a,
  author = {Amyay, B. and Herman, M. and Fayt, A. and Campargue, A. and Kassi, S.},
  title = {Acetylene, 12C2H2: Refined analysis of CRDS spectra around 1.52 μm},
  journal = {Journal of Molecular Spectroscopy},
  year = {2011},
  volume = {267},
  pages = {80-91},
  doi = {10.1016/j.jms.2011.02.015}
}
Abstract: One of the most important atmospheric composition products derived from the first EUMETSAT Meteorological Operational satellite (MetOp-A) is the total ozone column (TOC). For this purpose, MetOp-A has two instruments on board: the Global Ozone Monitoring Experiment 2 (GOME-2) that retrieves the TOC data from the backscattered solar ultraviolet-visible (UV-Vis) radiance, and the Infrared Atmospheric Sounding Interferometer (IASI) that uses the thermal infrared radiance to derive TOC data. This paper focuses on the simultaneous validation of the TOC data provided by these two MetOp-A instruments using the measurements recorded by five well-calibrated Brewer UV spectrophotometers located at the Iberian Peninsula during the complete 2009. The results show an excellent correlation between the ground-based data and the GOME-2 and IASI satellite observations (R2 higher than 0.91). Differences between the ground-based and satellite TOC data show that the IASI instrument significantly overestimates the Brewer measurements (about 4.4% when all five ground-based stations are jointly used). In contrast, the GOME-2 instrument shows a slight underestimation ( 1.6%). In addition, the absolute relative differences between the Brewer and GOME-2 data are quite smaller (about a factor higher than 2) than the Brewer-IASI absolute differences. The satellite viewing geometry (solar zenith angle and the view zenith angle) has no significant influence on the Brewer-satellite relative differences. Moreover, the analysis of these relative differences with respect to the ground-based TOC data indicates that GOME-2 instrument presents a slight underestimation for high TOC values. Finally, the IASI-GOME-2 correlation is high (R2 0.92), but with a mean relative difference of about ±6% which could be associated with the bias between UV-Vis and infrared spectroscopy used in the retrieval processes. © 2011 Elsevier Inc.
BibTeX:
@article{Anton2011,
  author = {Antón, M. and Loyola, D. and Clerbaux, C. and López, M. and Vilaplana, J.M. and Bañón, M. and Hadji-Lazaro, J. and Valks, P. and Hao, N. and Zimmer, W. and Coheur, P.F. and Hurtmans, D. and Alados-Arboledas, L.},
  title = {Validation of the MetOp-A total ozone data from GOME-2 and IASI using reference ground-based measurements at the Iberian Peninsula},
  journal = {Remote Sensing of Environment},
  year = {2011},
  volume = {115},
  pages = {1380-1386},
  doi = {10.1016/j.rse.2011.01.018}
}
Abstract: Aqua/hydroxo mononuclear Al3+ species coordinated by F - in aqueous solution are investigated using density functional theory (DFT B3LYP/6-311++G(d,p)) and the polarized continuum model (PCM). Optimized gas-phase geometries have been obtained for the species AlF(OH) n(H2O)m(2-n)+ in which n = 0, 1, 2, or 3 while (n + m) = 3, 4, or 5. Analysis of the Al-F, Al-O, and O-H bond lengths and the Al, F, O, and H natural charges of these complexes reveals clear trends that suggest increased acidity with decreasing coordination number (CN) and decreased water stability with increased hydrolysis. These observations are supported by the calculation and analysis of the dehydration and hydrolysis reaction Gibbs free energies δGaqueous dehydration and δGaqueous hydrolysis of the AlF(OH)n(H2O)m(2-n) + complexes, which clearly show a strong correlation between increased hydrolysis and a preference to coordinate fewer water molecules. The combination of the appropriate δGaqueous dehydration and δGaqueous hydrolysis values generate the aqueous Gibbs free energies relative to AlF(H2O)5 2+ and demonstrate the clear transition from a 6 to 5 to 4 coordinate species as a function of ligand hydrolysis. Calculation of the equilibrium mole fraction of each species as a function of pH shows that this system is largely dominated by the AlF(OH) 1(H2O)4 1+ and AlF(OH) 3 1- species. A comparison of structural and electronic data with the aqueous Al3+ complexes shows a remarkable similarity when plotted against the number negative ligands (F- or OH -), suggesting that the F- anion coordinates the Al 3+ cation in a similar way to the remaining OH- anions. The comparison of the calculated equilibrium mole fractions of each species displays important changes in the composition of our model system upon Al 3+ coordination by F- in the direction of increased acidity of these complexes. Our predicted decreased stability of the Al-water bond is in complete agreement with experimental NMR observations of an increased water exchange rate upon F- coordination of aqueous aluminum complexes. Our prediction of stable hydroxide ternary complexes is not in agreement with recent NMR data, which indicate that these complexes do not readily form. An explanation for this may lie in the increased lability of these complexes, which may lead to difficulties in NMR detection. © 2011 American Chemical Society.
BibTeX:
@article{Bogatko2011,
  author = {Bogatko, S. and Cauët, E. and Geerlings, P.},
  title = {Influence of F- coordination on Al3+ hydrolysis reactions from density functional theory calculations},
  journal = {Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  pages = {6910-6921},
  doi = {10.1021/jp112076r}
}
Abstract: The far infrared spectrum of methane is observed in emission in the stratosphere of Titan, Saturn's main satellite, allowing to determine its concentration in this environment. However this spectrum, which has a very low intensity because it is induced by the centrifugal distortion of the molecule only, was poorly characterized up to now. For the first time, it has been recorded, in absorption and at high resolution, at the AILES beamline of the SOLEIL synchrotron. Measurements have been performed for both pure methane and methanenitrogen mixtures. The intensities of methane lines and coefficients characterizing the broadening of these lines induced by collisions with nitrogen have been accurately determined. These new spectroscopic data, essential to analyze measurements in planetology, will most probably improve our understanding of physicochemical processes in planetary atmospheres where methane is often present.
BibTeX:
@article{Boudon2011,
  author = {Boudon, V. and Gabard, T. and Pirali, O. and Roy, P. and Brubach, J.-B. and Manceron, L. and Vander Auwera, J. and Coustenis, A. and Lellouch, E.},
  title = {The far infrared spectrum of methane in the Titan's atmosphere [Le spectre infrarouge lointain du méthane dans l'atmosphère de Titan]},
  journal = {Actualite Chimique},
  year = {2011},
  pages = {97-99}
}
Abstract: We present highly correlated multi-configuration Hartree-Fock (MCHF) calculations of the hyperfine structure of the 3p 5 2P o J levels of 33S - and 35, 37Cl. We obtain good agreement with observation. The hyperfine structure of the neutral sulphur 33S 3p 4 3P J lowest multiplet that has never been measured to the knowledge of the authors is also estimated theoretically. We discuss some interesting observations made on the description of the atomic core in MCHF theory. © 2011 IOP Publishing Ltd.
BibTeX:
@article{Carette2011,
  author = {Carette, T. and Godefroid, M.R.},
  title = {Ab initio calculations of the 33S 3p 4 3P J and 33S -/ 37, 35Cl 3p 5 2P o J hyperfine structures},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2011},
  volume = {44},
  article number = {105001},
  doi = {10.1088/0953-4075/44/10/105001}
}
Abstract: This work is an ab initio study of the 2p34S3/2o, and 2D3/2,5/2o states of C- and 2p23P0,1,2, 1D2, and 1S0 states of neutral carbon. We use the multiconfiguration Hartree-Fock approach, focusing on the accuracy of the wave function itself. We obtain all C - detachment thresholds, including correlation effects to about 0.5%. Isotope shifts and hyperfine structures are calculated. The achieved accuracy of the latter is of the order of 0.1 MHz. Intraconfiguration transition probabilities are also estimated. © 2011 American Physical Society.
BibTeX:
@article{Carette2011a,
  author = {Carette, T. and Godefroid, M.R.},
  title = {Theoretical study of the C- 4S3/2o and 2D3/2,5/2o bound states and C ground configuration: Fine and hyperfine structures, isotope shifts, and transition probabilities},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2011},
  volume = {83},
  article number = {062505},
  doi = {10.1103/PhysRevA.83.062505}
}
Abstract: Ab initio quantum mechanical methods provide microscopic insights into DNA characteristics and are, today, essential to the full interpretation and understanding of results obtained by experimental techniques. In this chapter we summarize the contributions of modern quantum chemicalcalculations to the determination of the electronic properties of DNA bases, isolated or embedded in base clusters. In particular, the calculations discussed concern the characterization of the molecular energy levels and potential energy surfaces, which shed light on ionization and charge migration along DNA molecules. We mainly consider the estimation of key parameters, such as ionization potentials (IPs) of DNA bases, which govern the charge injection into DNA. The effects of the stacking and H-bonding DNA base interactions and the solvation of DNA on these quantities are described. We also discuss the mechanisms of charge migration over stacked DNA bases. These aspects are illustrated by a survey of the literature and by our own selected recent results. © 2012 by Nova Science Publishers, Inc. All rights reserved.
BibTeX:
@book{Cauet2011,
  author = {Cauët, E.},
  title = {Quantum mechanical methods related to ionization of nucleic acid bases},
  journal = {DNA Microarrays, Synthesis and Synthetic DNA},
  year = {2011},
  pages = {255-284}
}
Abstract: The hypothetical protection of genes from oxidative damage provided by the G-rich telomeric overhangs located at the end of chromosomes, which consist, in humans, of single strands of TTAGGG sequence repeats, is investigated here. First principle Møller-Plesset perturbation theory calculations reveal that the TTAGGG human telomere sequence is particularly prone to oxidation and can act as a profound hole trap as deep as a sequence of five consecutive guanines. In addition, we show that the sequence dependence is very important and that modifications in the human telomeric sequence can induce crucial changes in the electronic structure of the sequence, with concomitant increase of the ionization energy. These theoretical results provide, for the first time, quantitative data indicating a high and unique efficiency of the human telomeric sequence as a trap in long-range hole migration which will aid in the design of subsequent experiments. ©Adenine Press (2011).
BibTeX:
@article{Cauet2011a,
  author = {Cauët, E.},
  title = {Unique hole-trapping property of the human telomere sequence},
  journal = {Journal of Biomolecular Structure and Dynamics},
  year = {2011},
  volume = {29},
  pages = {557-561}
}
Abstract: Hydrogen sulphide (H2S) is one of the main trace gases released from volcanoes with yearly global emissions estimated between 1 and 37 Tg. With sulfur dioxide (SO2, 15-21 Tg/year), it dominates the volcanic sulfur budget, and the emission ratio H2S:SO2 is an important geochemical probe for studying source conditions, sulfur chemistry and magma-water interactions. Contrary to SO2, measurements of H 2S are sparse and difficult. Here we report the first measurements of a large H2S plume from space. Observations were made with the infrared sounder IASI of the volcanic plume released after the 7-8 August 2008 eruption of Kasatochi volcano. The eruption was characterized by 5 consecutive explosive events. The first events were phreatomagmatic producing a plume rich in water vapor and poor in ash and SO2. We show that the observed H2S plume, calculated at 29±10 kT with integrated columns exceeding 140±25 Dobson Units (DU), is likely associated with these first explosions. H2S:SO2 ratios with maximum values of 12±2 are found, representative of redox conditions in the hydrothermal envelop. With a detection threshold of 25 DU, future space observations of H2S plumes are certain. These will be important for improving the atmospheric sulfur budget and characterizing the H2S:SO2 fingerprint of different eruptions. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{Clarisse2011,
  author = {Clarisse, L. and Coheur, P.-F. and Chefdeville, S. and Lacour, J.-L. and Hurtmans, D. and Clerbaux, C.},
  title = {Infrared satellite observations of hydrogen sulfide in the volcanic plume of the August 2008 Kasatochi eruption},
  journal = {Geophysical Research Letters},
  year = {2011},
  volume = {38},
  article number = {L10804},
  doi = {10.1029/2011GL047402}
}
Abstract: Using 3 years worth of IASI (the Infrared Atmospheric Sounder Interferometer aboard METOP-A) measurements, we have identified 24 major events of uplift and transport of anthropogenic sulfur dioxide. These were all first observed over East Asia, and could be traced for over 60 hours. On 7 November 2010 a sulfur dioxide plume was observed over Northeast China and tracked for five days to North America. We discuss this event in detail with respect to build up; uplift and in-plume chemistry. We found a host of trace gas enhancements in the plume (SO2, CO, PAN, CH3OH, HCOOH and C2H2). A reasonable to very good agreement was found with MOZART-4 modeled ambient columns for all species except methanol, which was underestimated by the model by an order of magnitude. We calculate correlations of the different species and give observational evidence of secondary in-plume formation of methanol and PAN. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{Clarisse2011a,
  author = {Clarisse, L. and Fromm, M. and Ngadi, Y. and Emmons, L. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F.},
  title = {Intercontinental transport of anthropogenic sulfur dioxide and other pollutants: An infrared remote sensing case study},
  journal = {Geophysical Research Letters},
  year = {2011},
  volume = {38},
  article number = {L19806},
  doi = {10.1029/2011GL048976}
}
Abstract: [1] Thermal infrared nadir sounders are ideal for observing total columns or vertical profiles of atmospheric gases such as water, carbon dioxide and ozone. High resolution sounders with a spectral resolution below 5 cm -1 can distinguish fine spectral features of trace gases. Forty years after the launch of the first hyperspectral sounder IRIS, we have now several state of the art instruments in orbit, with improved instrumental specifications. In this letter we give an overview of the trace gases which have been observed by infrared nadir sounders, focusing on new observations of the Infrared Atmospheric Sounding Interferometer (IASI). We present typical observations of 14 rare reactive trace gas species. Several species are reported here for the first time in nadir view, including nitrous acid, furan, acetylene, propylene, acetic acid, formaldehyde and hydrogen cyanide, observations which were made in a pyrocumulus cloud from the Australian bush fires of February 2009. Being able to observe this large number of reactive trace gases will likely improve our knowledge of source emissions and their impact on the environment and climate.
BibTeX:
@article{Clarisse2011b,
  author = {Clarisse, L. and R'Honi, Y. and Coheur, P.-F. and Hurtmans, D. and Clerbaux, C.},
  title = {Thermal infrared nadir observations of 24 atmospheric gases},
  journal = {Geophysical Research Letters},
  year = {2011},
  volume = {38},
  article number = {L10802},
  doi = {10.1029/2011GL047271}
}
Abstract: We evaluate climatologies of upper tropospheric ozone and nitric acid retrieved from two satellite instruments (ACE-FTS and OSIRIS) with long-term in situ measurements from aircraft (MOZAIC, CR-AVE, PRE-AVE, PEM Tropics, and TC4) and ozonesondes. A global chemical transport model (GEOS-Chem) is used to guide the evaluation and to relate sparse in situ measurements with the satellite retrievals. Both satellite retrievals generally reproduce broad ozone features in the upper troposphere such as summer enhancements in the northern subtropics and larger concentrations over the tropical Atlantic versus the tropical Pacific. These comparisons indicate biases in annual, tropical mean ozone concentrations from both ACE-FTS (10-13%) and OSIRIS (5%) relative to aircraft and ozonesonde observations. More uncertain evidence suggests that nitric acid from ACE-FTS has a positive mean bias of 15%. We demonstrate that an upper limit on the ozone production efficiency in the upper troposphere can be determined using ACE-FTS satellite measurements of O3 and HNO3. The resulting value of 196 (+34, -61) mol/mol is in broad agreement with model simulations. Higher OPE values inferred from ACE-FTS over the tropical Pacific (249 (+21, -68) mol/mol) than the tropical Atlantic (146 (+16, -41) mol/mol) reflect increasing ozone production efficiency with decreasing pollution. This analysis indicates a new capability of satellite observations to provide insight into ozone production in the tropical troposphere. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{Cooper2011,
  author = {Cooper, M. and Martin, R.V. and Sauvage, B. and Boone, C.D. and Walker, K.A. and Bernath, P.F. and McLinden, C.A. and Degenstein, D.A. and Volz-Thomas, A. and Wespes, C.},
  title = {Evaluation of ACE-FTS and OSIRIS Satellite retrievals of ozone and nitric acid in the tropical upper troposphere: Application to ozone production efficiency},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2011},
  volume = {116},
  article number = {D12306},
  doi = {10.1029/2010JD015056}
}
Abstract: The Eyjafjallajökull volcano in Iceland erupted explosively on 14 April 2010, emitting a plume of ash into the atmosphere. The ash was transported from Iceland toward Europe where mostly cloud-free skies allowed ground-based lidars at Chilbolton in England and Leipzig in Germany to estimate the mass concentration in the ash cloud as it passed overhead. The UK Met Office's Numerical Atmospheric-dispersion Modeling Environment (NAME) has been used to simulate the evolution of the ash cloud from the Eyjafjallajökull volcano during the initial phase of the ash emissions, 14-16 April 2010. NAME captures the timing and sloped structure of the ash layer observed over Leipzig, close to the central axis of the ash cloud. Relatively small errors in the ash cloud position, probably caused by the cumulative effect of errors in the driving meteorology en route, result in a timing error at distances far from the central axis of the ash cloud. Taking the timing error into account, NAME is able to capture the sloped ash layer over the UK. Comparison of the lidar observations and NAME simulations has allowed an estimation of the plume height time series to be made. It is necessary to include in the model input the large variations in plume height in order to accurately predict the ash cloud structure at long range. Quantitative comparison with the mass concentrations at Leipzig and Chilbolton suggest that around 3% of the total emitted mass is transported as far as these sites by small (<100 μm diameter) ash particles. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{Dacre2011,
  author = {Dacre, H.F. and Grant, A.L.M. and Hogan, R.J. and Belcher, S.E. and Thomson, D.J. and Devenish, B.J. and Marenco, F. and Hort, M.C. and Haywood, J.M. and Ansmann, A. and Mattis, I. and Clarisse, L.},
  title = {Evaluating the structure and magnitude of the ash plume during the initial phase of the 2010 Eyjafjallajökull eruption using lidar observations and NAME simulations},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2011},
  volume = {116},
  article number = {D00U03},
  doi = {10.1029/2011JD015608}
}
Abstract: Near infrared spectra of a carbon dioxide sample enriched with oxygen-17 have been recorded using a high resolution continuous scan Fourier transform interferometer fitted with a femto OPO laser source. Cavity enhanced absorption has been achieved in a static gas cell allowing for an optimal rms noise equivalent absorption of 4.4 × 10-9 cm-1 Hz -1/2 per spectral element to be reached, corresponding to αmin = 3 × 10-7 cm-1. The 3ν1 + ν3 and related hot bands in 12C17O2 and the 3ν1 + ν3 R-branch in 12C17O18O have been identified and rotationally analyzed. © 2011 Elsevier B.V. All rights reserved.
BibTeX:
@article{DeGhellinckDElseghemVaernewijck2011,
  author = {De Ghellinck D'Elseghem Vaernewijck, X. and Kassi, S. and Herman, M.},
  title = {17O12C17O and 18O 12C17O overtone spectroscopy in the 1.64 μm region},
  journal = {Chemical Physics Letters},
  year = {2011},
  volume = {514},
  pages = {29-31},
  doi = {10.1016/j.cplett.2011.08.025}
}
Abstract: CW-cavity ring down spectroscopy was used to record in a free jet expansion the spectrum of the absorption band in (12C2H 2)2 with origin at 6547.6 cm-1. It is a perpendicular band and corresponds to 2CH excitation in the hat unit of the T-shaped dimer. Calibration (better than ±1 × 10-3 cm-1 accuracy) and ring-down time (130 μs) were improved compared to a previous contribution (Didriche et al. Mol. Phys., 2010, 108, 2158-2164). A line-by-line analysis was achieved. Three series of lines were identified involving levels with A1 +, E+ and B 1 + ground state tunneling symmetries, confirming the spectral and symmetry analyses reported in the literature for the 1CH excitation band (Fraser et al. J. Chem. Phys., 1988, 89, 6028-6045). 164 vibration-rotation-tunneling lines were assigned in the K′a- K″a= 2-3,0-1,2-1 and 4-3 sub-bands and effective rigid rotor vibration-rotation constants were obtained by simultaneously fitting 1CH and 2CH lines with the same symmetry series. Perturbations affecting the Ka stacks, in particular, are reported. The tunneling frequency in 2CH is estimated to be ν2CH tunn = 270 MHz for the Ka = 0 stack. The rotational temperature is determined to be 23 K from relative line intensities and the lifetime of the dimer in the 2CH hat state is estimated to be 1 ns from individual line widths. © the Owner Societies 2011.
BibTeX:
@article{Didriche2011,
  author = {Didriche, K. and Lauzin, C. and Földes, T. and Golebiowski, D. and Herman, M. and Leforestier, C.},
  title = {High resolution overtone spectroscopy of the acetylene van der Waals dimer, (12C2H2)2},
  journal = {Physical Chemistry Chemical Physics},
  year = {2011},
  volume = {13},
  pages = {14010-14018},
  doi = {10.1039/c1cp20561g}
}
Abstract: The Measurements of Pollution in the Troposphere (MOPITT) retrievals are used as top-down constraints in an inversion for global CO emissions, for the past 10 years (from March 2000 to December 2009), at 8 day and 3.75° × 2.75° (longitude, latitude) resolution. The method updates a standard prior inventory and yields large increments in terms of annual regional budgets and seasonality. Our validation strategy consists in comparing our posterior-modeled concentrations with several sets of independent measurements: surface measurements, aircraft, and satellite. The posterior emissions, with a global 10 year average of 1430 TgCO/yr, are 37% higher than the prior ones, built from the EDGAR 3.2 and the GFEDv2 inventories (1038 TgCO/yr on average). In addition, they present some significant seasonal variations in the Northern Hemisphere that are not present in our prior nor in others' major inventories. Our results also exhibit some large interannual variability due to biomass burning emissions, climate, and socioeconomic factors; CO emissions range from 1504 TgCO (in 2007) to 1318 TgCO (in 2009). Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{Fortems-Cheiney2011,
  author = {Fortems-Cheiney, A. and Chevallier, F. and Pison, I. and Bousquet, P. and Szopa, S. and Deeter, M.N. and Clerbaux, C.},
  title = {Ten years of CO emissions as seen from Measurements of Pollution in the Troposphere (MOPITT)},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2011},
  volume = {116},
  article number = {D05304},
  doi = {10.1029/2010JD014416}
}
Abstract: Within the lowest-order relativistic approximation (∼v 2/c2) and to first order in me/M, the tensorial form of the relativistic corrections of the nuclear recoil Hamiltonian is derived, opening interesting perspectives for calculating isotope shifts in the multiconfiguration Dirac-Hartree-Fock framework. Their calculation is illustrated for selected Li-, B- and C-like ions. This work underlines the fact that the relativistic corrections to the nuclear recoil are definitively necessary for obtaining reliable isotope shift values. © 2011 IOP Publishing Ltd.
BibTeX:
@article{Gaidamauskas2011,
  author = {Gaidamauskas, E. and Nazé, C. and Rynkun, P. and Gaigalas, G. and Jönsson, P. and Godefroid, M.},
  title = {Tensorial form and matrix elements of the relativistic nuclear recoil operator},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2011},
  volume = {44},
  article number = {175003},
  doi = {10.1088/0953-4075/44/17/175003}
}
Abstract: The updated 2009 edition of the spectroscopic database GEISA (Gestion et Etude des Informations Spectroscopiques Atmosphériques; Management and Study of Atmospheric Spectroscopic Information) is described in this paper. GEISA is a computer-accessible system comprising three independent sub-databases devoted, respectively, to: line parameters, infrared and ultraviolet/visible absorption cross-sections, microphysical and optical properties of atmospheric aerosols. In this edition, 50 molecules are involved in the line parameters sub-database, including 111 isotopologues, for a total of 3,807,997 entries, in the spectral range from 10-6 to 35,877.031cm-1.The successful performances of the new generation of hyperspectral sounders depend ultimately on the accuracy to which the spectroscopic parameters of the optically active atmospheric gases are known, since they constitute an essential input to the forward radiative transfer models that are used to interpret their observations. Currently, GEISA is involved in activities related to the assessment of the capabilities of IASI (Infrared Atmospheric Sounding Interferometer; http://smsc.cnes.fr/IASI/index.htm) on board the METOP European satellite through the GEISA/IASI database derived from GEISA. Since the Metop-A (http://www.eumetsat.int) launch (19 October 2006), GEISA is the reference spectroscopic database for the validation of the level-1 IASI data. Also, GEISA is involved in planetary research, i.e., modeling of Titan's atmosphere, in the comparison with observations performed by Voyager, or by ground-based telescopes, and by the instruments on board the Cassini-Huygens mission.GEISA, continuously developed and maintained at LMD (Laboratoire de Météorologie Dynamique, France) since 1976, is implemented on the IPSL/CNRS (France) "Ether" Products and Services Centre WEB site (http://ether.ipsl.jussieu.fr), where all archived spectroscopic data can be handled through general and user friendly associated management software facilities. More than 350 researchers are registered for on line use of GEISA. © 2011 Elsevier Ltd.
BibTeX:
@article{Jacquinet-Husson2011,
  author = {Jacquinet-Husson, N. and Crepeau, L. and Armante, R. and Boutammine, C. and Chédin, A. and Scott, N.A. and Crevoisier, C. and Capelle, V. and Boone, C. and Poulet-Crovisier, N. and Barbe, A. and Campargue, A. and Chris Benner, D. and Benilan, Y. and Bézard, B. and Boudon, V. and Brown, L.R. and Coudert, L.H. and Coustenis, A. and Dana, V. and Devi, V.M. and Fally, S. and Fayt, A. and Flaud, J.-M. and Goldman, A. and Herman, M. and Harris, G.J. and Jacquemart, D. and Jolly, A. and Kleiner, I. and Kleinböhl, A. and Kwabia-Tchana, F. and Lavrentieva, N. and Lacome, N. and Xu, L.-H. and Lyulin, O.M. and Mandin, J.-Y. and Maki, A. and Mikhailenko, S. and Miller, C.E. and Mishina, T. and Moazzen-Ahmadi, N. and Müller, H.S.P. and Nikitin, A. and Orphal, J. and Perevalov, V. and Perrin, A. and Petkie, D.T. and Predoi-Cross, A. and Rinsland, C.P. and Remedios, J.J. and Rotger, M. and Smith, M.A.H. and Sung, K. and Tashkun, S. and Tennyson, J. and Toth, R.A. and Vandaele, A.-C. and Vander Auwera, J.},
  title = {The 2009 edition of the GEISA spectroscopic database},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2011},
  volume = {112},
  pages = {2395-2445},
  doi = {10.1016/j.jqsrt.2011.06.004}
}
Abstract: The room temperature high resolution infrared spectrum of C 2H 6 between 1330 and 1610cm -1, the region of the 6 and 8 fundamentals, has been re-investigated owing to the relevance of this spectral region in atmospheric and planetary applied research. The assignments of transitions from the ground vibrational state to the upper states v 6, v 8, v 4+v 12 and 2v 4+v 9 (4592 in total) and from the lower state v 4 to the upper state v 4+v 8 (1090 lines) have been considerably extended with respect to our previous work [F. Lattanzi, C. di Lauro and J. Vander Auwera, J. Mol. Spectrosc. 248 (2008) 134-145], especially for the hot transitions. In particular, three new series of perturbation activated transitions were found, with ΔK=±2, made observable by the resonance of the type l(Δl=±2, ΔK=±1) within v 8. Also, new P-transitions to v 6 were found, made observable by the x,y-Coriolis resonance with v 8, at the values of K from 15 to 18. The extension of the assignments in the high frequency wing of v 8 and their analysis allowed the discovery of two additional resonance interactions. The first interaction, a higher order Coriolis-type between v 8(±K, l=±1) and v 6(K±2, l=0), induces a few detectable transitions to v 6 with ΔK=3. The second interaction, of the type l(Δl=±2, ΔK=±1), comes to resonance between v 8(k=19, ±l=±1) and 2v 4+v 9 (k=±20, l=±1). This last resonance and the x,y-Coriolis resonance of v 6 and 2v 4+v 9 allows one to observe several transitions to the 2v 4+v 9 vibrational state. The extension of the assignments in the (v 4+v 8)-v 4 hot band allowed discovery of a resonance interaction of the type l(Δl=±2, ΔK=±1) between the states v 4+v 8 and 2v 4+v 12, in addition to their well known Fermi-type interaction. The K-values before and after the level crossing could be determined for both interactions. Better values were also determined for the J-structure parameters B, D J and D JK in the v 4 state, from 410 selected combination differences. Least squares fit calculations, performed on 2084 upper state energy levels for the cold system (RMS of 3.69×10 -3cm -1) and 500 for the hot system (RMS of 6.62×10 -3cm -1), required a more sophisticated Hamiltonian model than in our previous work. Copyright © 2011 Taylor and Francis Group, LLC.
BibTeX:
@article{Lattanzi2011,
  author = {Lattanzi, F. and Di Lauro, C. and Auwera, J.V.},
  title = {Extended analysis of the high resolution spectrum of C 2H 6 near 7μm: The v 6, v 8, v 4+ v 12, 2v 4+v 9 vibrational system, and associated hot transitions},
  journal = {Molecular Physics},
  year = {2011},
  volume = {109},
  pages = {2219-2235},
  doi = {10.1080/00268976.2011.604353}
}
Abstract: The Fourier transform infrared spectrum of ethane between 2860 and 3060 cm-1 has been re-investigated under high resolution at 229 K. The infrared absorption in this region is due mainly to the CH stretching fundamentals ν5 (parallel band) and ν7 (degenerate perpendicular band), and to the parallel combination system ν8 + ν11 (A4s, A3s). All the relevant perturbation mechanisms affecting the observed absorption patterns have been clarified. In particular, the main perturbers of the ν7 state are identified to be the degenerate vibrational combination states ν8 + ν11 (l-type interaction) and ν3 + 2ν4 + ν8 (Fermi-type interaction). Because of the last interaction, the K″ΔK = -6 transitions occur with intensities comparable to both the infrared active fundamental ν7 and the almost dark combination ν3 + 2ν4 + ν8. The parallel combination system ν8 + ν11 (A 4s, A3s) is overlapped and heavily perturbed by the nearby parallel system ν4 + ν11 + ν12 (A4s, A3s), whose K-structure is spread by the strong z-Coriolis interaction of its two vibrational components. In this work, 95 new transitions to the perturbers of ν7 have been assigned. They belong mostly to the degenerate vibrational states ν8 + ν11 (E1d) and ν3 + 2ν4 + ν8 (E1d), and to the parallel system ν8 + ν11 (A4s, A3s). A least squares fit calculation, limited to the ν7 degenerate fundamental and its degenerate perturbers ν8 + ν11, ν3 + 2ν4 + ν8, ν4 + ν11 + ν12, and ν3 + 3ν4 + ν12 was performed. From the results of this fit, we created a line-by-line database containing the molecular parameters for 4969 transitions in these five bands of 12C2H6. Finally, we identified the degenerate combination band ν2 + ν8 (62 observed transitions) to be the main perturber (x, y-Coriolis-type interaction) of the parallel fundamental ν5. © 2011 Elsevier Inc. All rights reserved.
BibTeX:
@article{Lattanzi2011a,
  author = {Lattanzi, F. and Di Lauro, C. and Vander Auwera, J.},
  title = {Toward the understanding of the high resolution infrared spectrum of C 2H6 near 3.3 μm},
  journal = {Journal of Molecular Spectroscopy},
  year = {2011},
  volume = {267},
  pages = {71-79},
  doi = {10.1016/j.jms.2011.02.003}
}
Abstract: Infrared spectra of the weakly-bound C 2H 2-CO 2 and C 2H 2-N 2O complexes in the region of the 2CH acetylene overtone band (∼1.52μm) were recorded using CW-cavity ring down spectroscopy in a continuous supersonic expansion. A new, c-type combination band is observed in each case. The rotational analysis of low J, K lines is performed and rotational constants are obtained. The band origins are 40.491(2) and 40.778(2) cm -1 higher in energy than the 2CH excitation bands for C 2H 2-CO 2 and C 2H 2-N 2O, respectively. The combination band is assigned in each case as involving intermolecular torsional excitation combined to 2CH. The values of the torsional vibrational frequency and of the x CH/torsion anharmonicity constant are briefly discussed. Copyright © 2011 Taylor and Francis Group, LLC.
BibTeX:
@article{Lauzin2011,
  author = {Lauzin, C. and Didriche, K. and Földes, T. and Herman, M.},
  title = {Torsional excitation in the 2CH vibrational overtone of the C 2H 2-CO 2 and C 2H 2-N 2O van der Waals complexes},
  journal = {Molecular Physics},
  year = {2011},
  volume = {109},
  pages = {2105-2109},
  doi = {10.1080/00268976.2011.593572}
}
Abstract: We report the definition and refinement of a new first principles potential for the acetylene dimer. The ab initio calculations were performed with the DFT-SAPT combination of symmetry-adapted intermolecular perturbation method and density functional theory, and fitted to a model site-site functional form. Comparison of the calculated microwave spectrum with experimental data revealed that the barriers to isomerization were too low. This potential was refined by fitting the model parameters in order to reproduce the observed transitions, an excellent agreement within ∼1 MHz being achieved. © 2011 American Institute of Physics.
BibTeX:
@article{Leforestier2011,
  author = {Leforestier, C. and Tekin, A. and Jansen, G. and Herman, M.},
  title = {First principles potential for the acetylene dimer and refinement by fitting to experiments},
  journal = {Journal of Chemical Physics},
  year = {2011},
  volume = {135},
  article number = {234306},
  doi = {10.1063/1.3668283}
}
Abstract: The equilibrium structure of acetylene (also named ethyne) has been reinvestigated to resolve the small discrepancies noted between different determinations. The size of the system as well as the large amount of available experimental data provides the quite unique opportunity to check the magnitude and relevance of various contributions to equilibrium structure as well as to verify the accuracy of experimental results. With respect to pure theoretical investigation, quantum-chemical calculations at the coupled-cluster level have been employed together with extrapolation to the basis set limit, consideration of higher excitations in the cluster operator, inclusion of core correlation effects as well as relativistic and diagonal Born-Oppenheimer corrections. In particular, it is found that the extrapolation to the complete basis set limit, the inclusion of higher excitations in the electronic-correlation treatment and the relativistic corrections are of the same order of magnitude. It also appears that a basis set as large as a core-valence quintuple-zeta set is required for accurately accounting for the inner-shell correlation contribution. From a pure experimental point of view, the equilibrium structure has been determined using very accurate rotational constants recently obtained by a global analysis (that is to say that all non-negligible interactions are explicitely included in the Hamiltonian matrix) of rovibrational spectra. Finally, a semi-experimental equilibrium structure (where the equilibrium rotational constants are obtained from the experimental ground state rotational constants and computed rovibrational corrections) has been obtained from the available experimental ground-state rotational constants for ten isotopic species corrected for computed vibrational corrections. Such a determination led to the revision of the ground-state rotational constants of two isotopologues, thus showing that structural determination is a good method to identify errors in experimental rotational constants. The three structures are found in a very good agreement, and our recommended values are rCC 120.2958(7) pm and rCH 106.164(1) pm. © 2011 American Institute of Physics.
BibTeX:
@article{Lievin2011,
  author = {Liévin, J. and Demaison, J. and Herman, M. and Fayt, A. and Puzzarini, C.},
  title = {Comparison of the experimental, semi-experimental and ab initio equilibrium structures of acetylene: Influence of relativisitic effects and of the diagonal Born-Oppenheimer corrections},
  journal = {Journal of Chemical Physics},
  year = {2011},
  volume = {134},
  article number = {064119},
  doi = {10.1063/1.3553203}
}
Abstract: We investigate the dynamics of the photodissociation of the helium hydride ion HeH+ by XUV radiation with the aim to establish a detailed comparison with a recent experimental work carried out at the FLASH free electron laser using both vibrationally hot and cold ions. We determine the corresponding rovibrational distributions using a dissociative charge transfer setup and the same source conditions as in the FLASH experiment. Using a nonadiabatic time-dependent wave-packet method, we calculate the partial photodissociation cross sections for the n=1-3 coupled electronic states of HeH+. We find good agreement with the experiment for the cross section into the He + H+ dissociative channel. On the other hand, we show that the experimental observation of the importance of the electronic states with n&gt;3 cannot be well explained theoretically, especially for cold (v=0) ions. We find a good agreement with the experiment on the relative contribution of the Σ and Π states to the cross section for the He + + H channel, but only a qualitative one for the He + H+ channel. We discuss the factors that could explain the remaining discrepancies between theory and experiment. © 2011 American Physical Society.
BibTeX:
@article{Loreau2011b,
  author = {Loreau, J. and Lecointre, J. and Urbain, X. and Vaeck, N.},
  title = {Rovibrational analysis of the XUV photodissociation of HeH+ ions},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2011},
  volume = {84},
  article number = {053412},
  doi = {10.1103/PhysRevA.84.053412}
}
Abstract: We present a theoretical study of the isotope effect arising from the replacement of H by T in the charge-transfer collision H(n=2) + He +(1s) at low energy. Using a quasimolecular approach and a time-dependent wave-packet method, we compute the cross sections for the reaction including the effects of the nonadiabatic radial and rotational couplings. For H(2s) + He+(1s) collisions, we find a strong isotope effect at energies below 1 eV/amu for both singlet and triplet states. We find a much smaller isotopic dependence of the cross section for H(2p) + He +(1s) collisions in triplet states, and no isotope effect in singlet states. We explain the isotope effect on the basis of the potential energy curves and the nonadiabatic couplings, and we evaluate the importance of the isotope effect on the charge-transfer rate coefficients. © 2011 American Physical Society.
BibTeX:
@article{Loreau2011a,
  author = {Loreau, J. and Ryabchenko, S. and Dalgarno, A. and Vaeck, N.},
  title = {Isotope effect in charge-transfer collisions of H with He+},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2011},
  volume = {84},
  article number = {052720},
  doi = {10.1103/PhysRevA.84.052720}
}
Abstract: A quantal study of the rotational excitation of nitrogen molecules by sodium atoms is carried out. We present the two-dimensional potential energy surface of the NaN2 complex, with the N2 molecule treated as a rigid rotor. The interaction potential is computed using the spin unrestricted coupled-cluster method with single, double, and perturbative triple excitations (UCCSD(T)). The long-range part of the potential is constructed from the dynamic electric dipole polarizabilities of Na and N2. The total, differential, and momentum transfer cross sections for rotationally elastic and inelastic transitions are calculated using the close-coupling approach for energies between 5 cm-1 and 1500 cm-1. The collisional and momentum transfer rate coefficients are calculated for temperatures between 100 K and 300 K, corresponding to the conditions under which Na-N2 collisions occur in the mesosphere. © 2011 American Institute of Physics.
BibTeX:
@article{Loreau2011,
  author = {Loreau, J. and Zhang, P. and Dalgarno, A.},
  title = {Elastic scattering and rotational excitation of nitrogen molecules by sodium atoms},
  journal = {Journal of Chemical Physics},
  year = {2011},
  volume = {135},
  article number = {174301},
  doi = {10.1063/1.3653983}
}
Abstract: We report measurements of self- and nitrogen-pressure broadening of the P(11) line in the ν1 + ν3 combination band of acetylene at 195 739.649 5135(80) GHz by absorption of radiation emitted by an extended cavity diode laser referenced to a femtosecond frequency comb. Broadening, shift and narrowing parameters were determined at 296 K. For the most appropriate, hard collision, model in units of cm-1/atm, we find 0.146317(27), 0.047271(104) and -0.0070819(22) for the acetylene self-broadening, narrowing and shift, and 0.081129(35), 0.022940(74) and -0.0088913(25) respectively, for the nitrogen-broadening parameters. The uncertainties are expressed as one standard deviation (in parenthesis) in units of the last digit reported. These parameters are 2-3 orders of magnitude more precise than those reported in previous measurements. Similar analyses of the experimental data using soft collision and simple Voigt lineshape models were made for comparison. © 2011 Elsevier Inc. All rights reserved.
BibTeX:
@article{McRaven2011,
  author = {McRaven, C.P. and Cich, M.J. and Lopez, G.V. and Sears, T.J. and Hurtmans, D. and Mantz, A.W.},
  title = {Frequency comb-referenced measurements of self- and nitrogen-broadening in the ν1 + ν3 band of acetylene},
  journal = {Journal of Molecular Spectroscopy},
  year = {2011},
  volume = {266},
  pages = {43-51},
  doi = {10.1016/j.jms.2011.02.016}
}
Abstract: Recently, a high temperature source has been used to produce high temperature emission spectra of acetylene in the 3 γm spectral range, under Doppler limited resolution, and the complete spectral assignment has been performed using a global rovibrational Hamiltonian [Amyay B, Robert S, Herman M, Fayt A, Raghavendra B, Moudens A et al. Vibration-rotation pattern in acetylene (II): Introduction to Coriolis coupling in the global model and analysis of emission spectra of hot acetylene around 3 γm. J Chem Phys 2009;131:114301]. The present investigation focuses on the relative emission line intensities which are observed to be affected. The strongest lines intensity may be considerably reduced for high column density acetylene samples, hence affecting the 3:1 ortho:para intensity ratio. A radiative model is developed to take into account the effects generated by the strong opacity of the acetylene samples including self-absorption and absorption of the radiation emitted by the hot environment. The model is used to extract the absolute concentration of the high temperature acetylene samples from the observed relative spectral intensities. The relevance of the procedure for infrared remote sensing in high temperature astrophysical environments, such as circumstellar envelopes of cool carbon rich evolved stars, is discussed. © 2010 Elsevier Ltd.
BibTeX:
@article{Moudens2011,
  author = {Moudens, A. and Georges, R. and Benidar, A. and Amyay, B. and Herman, M. and Fayt, A. and Plez, B.},
  title = {Emission spectroscopy from optically thick laboratory acetylene samples at high temperature},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2011},
  volume = {112},
  pages = {540-549},
  doi = {10.1016/j.jqsrt.2010.10.012}
}
Abstract: In this study we have retrieved the line intensities, self broadened widths, pressure-induced shifts and selected line mixing coefficients for 20 R-branch transitions in the ν1 + ν2 + ν4 + ν5 band of acetylene. The spectra were recorded using our 3-channels diode laser spectrometer, a temperature controlled cell of fixed length and a second, room temperature cell. The Voigt and speed-dependent Voigt profiles with inclusion of line mixing effects were used to retrieve the line parameters. We determined the temperature dependencies for line broadening, shift and line mixing coefficients. © 2011 Elsevier Inc. All rights reserved.
BibTeX:
@article{Povey2011,
  author = {Povey, C. and Predoi-Cross, A. and Hurtmans, D.R.},
  title = {Line shape study of acetylene transitions in the ν1 + ν2 + ν4 + ν5 band over a range of temperatures},
  journal = {Journal of Molecular Spectroscopy},
  year = {2011},
  volume = {268},
  pages = {177-188},
  doi = {10.1016/j.jms.2011.04.020}
}
Abstract: The infrared spectrum of 12C2HD has been studied using synchrotron radiation at the far-infrared beam line, Canadian Light Source, Saskatoon, Canada. The spectra were recorded at a resolution of 0.00096 cm-1 in the 60 to 360 cm-1 range using a Bruker IFS 125 Fourier transform spectrometer. In total, 821 vibration rotation lines were observed and assigned to the P(J), Q(J) and R(J) transitions of the v 5←v4 difference band and associated hot bands with J up to 35 and (v4+v5) up to 3. These new transitions were analysed together with 4518 transitions involving bending states with (v I+v5) up to 3 available in the literature. The spectroscopic parameters obtained from the fit reproduce 4909 transitions with a standard deviation of 0.00028 cm-1. The v5←v 4 bands of 13CH12CD and 12CH 13CD were also detected and analysed. © 2011 Taylor &amp; Francis.
BibTeX:
@article{Predoi-Cross2011,
  author = {Predoi-Cross, A. and Herman, M. and Fusina, L. and Di Lonardo, G.},
  title = {The far-infrared spectrum of 12C2HD},
  journal = {Molecular Physics},
  year = {2011},
  volume = {109},
  pages = {559-563},
  doi = {10.1080/00268976.2010.536170}
}
Abstract: Methanol (CH3OH) and formic acid (HCOOH) are among the most abundant volatile organic compounds present in the atmosphere. In this work, we derive the global distributions of these two organic species using for the first time the Infrared Atmospheric Sounding Interferometer (IASI) launched onboard the MetOp-A satellite in 2006. This paper describes the method used and provides a first critical analysis of the retrieved products. The retrieval process follows a two-step approach in which global distributions are first obtained on the basis of a simple radiance indexing (transformed into brightness temperatures), and then mapped onto column abundances using suitable conversion factors. For methanol, the factors were calculated using a complete retrieval approach in selected regions. In the case of formic acid, a different approach, which uses a set of forward simulations for representative atmospheres, has been used. In both cases, the main error sources are carefully determined: the average relative error on the column for both species is estimated to be about 50%, increasing to about 100% for the least favorable conditions. The distributions for the year 2009 are discussed in terms of seasonality and source identification. Time series comparing methanol, formic acid and carbon monoxide in different regions are also presented. © 2011 Author(s).
BibTeX:
@article{Razavi2011,
  author = {Razavi, A. and Karagulian, F. and Clarisse, L. and Hurtmans, D. and Coheur, P.F. and Clerbaux, C. and Müller, J.F. and Stavrakou, T.},
  title = {Global distributions of methanol and formic acid retrieved for the first time from the IASI/MetOp thermal infrared sounder},
  journal = {Atmospheric Chemistry and Physics},
  year = {2011},
  volume = {11},
  pages = {857-872},
  doi = {10.5194/acp-11-857-2011}
}
Abstract: Electron holes are known to migrate along the DNA or RNA duplexes and to localize preferentially on successive guanines. The stationary point conformations of Gua pairs that can trap or let pass these holes have been characterized by quantum chemistry calculations. Here we show their recurrent occurrence in DNA and RNA X-ray structures, often in quadruplex conformations or in interaction with proteins, ligands or metal ions. These findings give support to the biological, possibly regulatory, roles of charge migration in cell functioning. ©Adenine Press (2011).
BibTeX:
@article{Rooman2011,
  author = {Rooman, M. and Cauët, E. and Liévin, J. and Wintjens, R.},
  title = {Conformations consistent with charge migration observed in DNA and RNA X-ray structures},
  journal = {Journal of Biomolecular Structure and Dynamics},
  year = {2011},
  volume = {28},
  pages = {949-954}
}
Abstract: Presently only limited sets of tropospheric ammonia (NH3) measurements in the Earth's atmosphere have been reported from satellite and surface station measurements, despite the well-documented negative impact of NH3 on the environment and human health. Presented here is a detailed description of the satellite retrieval strategy and analysis for the Tropospheric Emission Spectrometer (TES) using simulations and measurements. These results show that: (i) the level of detectability for a representative boundary layer TES NH3 mixing ratio value is ∼0.4 ppbv, which typically corresponds to a profile that contains a maximum level value of ∼1 ppbv; (ii) TES NH3 retrievals generally provide at most one degree of freedom for signal (DOFS), with peak sensitivity between 700 and 900 mbar; (iii) TES NH3 retrievals show significant spatial and seasonal variability of NH3 globally; (iv) initial comparisons of TES observations with GEOS-CHEM estimates show TES values being higher overall. Important differences and similarities between modeled and observed seasonal and spatial trends are noted, with discrepancies indicating areas where the timing and magnitude of modeled NH3 emissions from agricultural sources, and to lesser extent biomass burning sources, need further study. © Author(s) 2011. CC Attribution 3.0 License.
BibTeX:
@article{Shephard2011,
  author = {Shephard, M.W. and Cady-Pereira, K.E. and Luo, M. and Henze, D.K. and Pinder, R.W. and Walker, J.T. and Rinsland, C.P. and Bash, J.O. and Zhu, L. and Payne, V.H. and Clarisse, L.},
  title = {TES ammonia retrieval strategy and global observations of the spatial and seasonal variability of ammonia},
  journal = {Atmospheric Chemistry and Physics},
  year = {2011},
  volume = {11},
  pages = {10743-10763},
  doi = {10.5194/acp-11-10743-2011}
}
Abstract: During the POLARCAT summer campaign in 2008, two episodes (2g-5 July and 7g-10 July 2008) occurred where low-pressure systems traveled from Siberia across the Arctic Ocean towards the North Pole. The two cyclones had extensive smoke plumes from Siberian forest fires and anthropogenic sources in East Asia embedded in their associated air masses, creating an excellent opportunity to use satellite and aircraft observations to validate the performance of atmospheric transport models in the Arctic, which is a challenging model domain due to numerical and other complications. Here we compare transport simulations of carbon monoxide (CO) from the Lagrangian transport model FLEXPART and the Eulerian chemical transport model TOMCAT with retrievals of total column CO from the IASI passive infrared sensor onboard the MetOp-A satellite. The main aspect of the comparison is how realistic horizontal and vertical structures are represented in the model simulations. Analysis of CALIPSO lidar curtains and in situ aircraft measurements provide further independent reference points to assess how reliable the model simulations are and what the main limitations are. The horizontal structure of mid-latitude pollution plumes agrees well between the IASI total column CO and the model simulations. However, finer-scale structures are too quickly diffused in the Eulerian model. Applying the IASI averaging kernels to the model data is essential for a meaningful comparison. Using aircraft data as a reference suggests that the satellite data are biased high, while TOMCAT is biased low. FLEXPART fits the aircraft data rather well, but due to added background concentrations the simulation is not independent from observations. The multi-data, multi-model approach allows separating the influences of meteorological fields, model realisation, and grid type on the plume structure. In addition to the very good agreement between simulated and observed total column CO fields, the results also highlight the difficulty to identify a data set that most realistically represents the actual pollution state of the Arctic atmosphere. © 2011 Adis Data Information BV. All rights reserved.
BibTeX:
@article{Sodemann2011,
  author = {Sodemann, H. and Pommier, M. and Arnold, S.R. and Monks, S.A. and Stebel, K. and Burkhart, J.F. and Hair, J.W. and Diskin, G.S. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Schlager, H. and Blechschmidt, A.-M. and Kristjánsson, J.E. and Stohl, A.},
  title = {Episodes of cross-polar transport in the Arctic troposphere during July 2008 as seen from models, satellite, and aircraft observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2011},
  volume = {11},
  pages = {3631-3651},
  doi = {10.5194/acp-11-3631-2011}
}
BibTeX:
@article{Softley2011,
  author = {Softley, T.P. and Boudon, V. and De Natale, P. and Fusina, L. and Herman, M. and Quack, M.},
  title = {22nd Colloquium on High Resolution Molecular Spectroscopy: Special Issue dedicated to Gianfranco di Lonardo},
  journal = {Molecular Physics},
  year = {2011},
  volume = {109},
  pages = {2069-2070},
  doi = {10.1080/00268976.2011.620772}
}
Abstract: The spectroscopy of the ZrF radical, produced by a laser ablation-molecular beam experimental setup, has been investigated for the first time using a two-color two-photon (1 + 1′) REMPI scheme and time-of-flight (TOF) mass spectrometry detection. The region of intense bands 400-470 nm has been studied, based upon the first spectroscopic observations of the isovalent ZrCl radical by Carroll and Daly.(1)The overall spectrum observed is complex. However, simultaneous and individual ion detection of the five naturally occurring isotopologues of ZrF has provided a crucial means of identifying band origins and characterization via the isotopic shift, δ iso, of the numerous vibronic transitions recorded. Hence, five (0-0) transitions, of which only two were free of overlap with other transitions, have been identified. The most intense (0-0) transition at 23113 cm -1 presented an unambiguously characteristic RQP rotational structure. From rotational contour simulations of the observed spectra, the nature of the ground electronic state is found to be unambiguously of 2Δ symmetry, leading to the assignment of this band as (0-0) 2Δ ← X 2Δ at 23113 cm -1. A set of transitions (1-0) 2Δ ← X 2Δ at 22105 cm -1 and (2-0) 2 ← X 2Δ at 22944 cm -1 involving the X 2Δ state has also been identified and analyzed. Furthermore, a second series of transitions with lesser intensity has also been related to the long-lived metastable 4Σ - state: (3-0) 4Π -1/2 ← 4Σ - at 21801 cm -1, (2-0) 4Π -1/2 ← 4Σ - at 21285 cm -1 and (2-0) 4Σ - ← 4Σ - at 23568 cm -1. These spectroscopic assignments are supported by MRCI ab initio calculations, performed using the MOLPRO quantum chemistry package, and show that the low-lying excited states of the ZrF radical are the 4Σ - and 4 states lying at 2383 and 4179 cm -1 respectively above the ground X 2Δ state. The difference in the nature of ground state and ordering of the first electronic states with TiF (X 4)(2-4)and ZrCl,(5)respectively, is examined in terms of the ligand field theory (LFT)(7)applied to diatomic molecules. These results give a precise description of the electronic structure of the low lying electronic states of the ZrF transition metal radical. © 2011 American Chemical Society.
BibTeX:
@article{Soorkia2011,
  author = {Soorkia, S. and Shafizadeh, N. and Liévin, J. and Gaveau, M.-A. and Pothier, C. and Mestdagh, J.-M. and Soep, B. and Field, R.W.},
  title = {Determination of the ground electronic state in transition metal halides: ZrF},
  journal = {Journal of Physical Chemistry A},
  year = {2011},
  volume = {115},
  pages = {9620-9632},
  doi = {10.1021/jp2004997}
}
Abstract: This study provides improved methanol emission estimates on the global scale, in particular for the largest methanol source, the terrestrial biosphere, and for biomass burning. To this purpose, one complete year of spaceborne measurements of tropospheric methanol columns retrieved for the first time by the thermal infrared sensor IASI aboard the MetOp satellite are compared with distributions calculated by the IMAGESv2 global chemistry-transport model. Two model simulations are performed using a priori biogenic methanol emissions either from the new MEGANv2.1 emission model, which is fully described in this work and is based on net ecosystem flux measurements, or from a previous parameterization based on net primary production by Jacob et al. (2005). A significantly better model performance in terms of both amplitude and seasonality is achieved through the use of MEGANv2.1 in most world regions, with respect to IASI data, and to surface- and air-based methanol measurements, even though important discrepancies over several regions are still present. As a second step of this study, we combine the MEGANv2.1 and the IASI column abundances over continents in an inverse modelling scheme based on the adjoint of the IMAGESv2 model to generate an improved global methanol emission source. The global optimized source totals 187 Tg yr&minus;1 with a contribution of 100 Tg yr&minus;1 from plants, only slightly lower than the a priori MEGANv2.1 value of 105 Tg yr&minus;1. Large decreases with respect to the MEGANv2.1 biogenic source are inferred over Amazonia (up to 55 %) and Indonesia (up to 58 %), whereas more moderate reductions are recorded in the Eastern US (20-25 %) and Central Africa (25-35 %). On the other hand, the biogenic source is found to strongly increase in the arid and semi-arid regions of Central Asia (up to a factor of 5) and Western US (factor of 2), probably due to a source of methanol specific to these ecosystems which is unaccounted for in the MEGANv2.1 inventory. The most significant error reductions achieved by the optimization concern the derived biogenic emissions over the Amazon and over the Former Soviet Union. The robustness of the derived fluxes to changes in convective updraft fluxes, in methanol removal processes, and in the choice of the biogenic a priori inventory is assessed through sensitivity inversions. Detailed comparisons of the model with a number of aircraft and surface observations of methanol, as well as new methanol measurements in Europe and in the Reunion Island show that the satellite-derived methanol emissions improve significantly the agreement with the independent data, giving thus credence to the IASI dataset. © 2011 Author(s).
BibTeX:
@article{Stavrakou2011,
  author = {Stavrakou, T. and Guenther, A. and Razavi, A. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Karagulian, F. and De MaziÃ̈re, M. and Vigouroux, C. and Amelynck, C. and Schoon, N. and Laffineur, Q. and Heinesch, B. and Aubinet, M. and Rinsland, C. and Müller, J.-F.},
  title = {First space-based derivation of the global atmospheric methanol emission fluxes},
  journal = {Atmospheric Chemistry and Physics},
  year = {2011},
  volume = {11},
  pages = {4873-4898},
  doi = {10.5194/acp-11-4873-2011}
}
Abstract: The Aprilg-May, 2010 volcanic eruptions of Eyjafjallajökull, Iceland caused significant economic and social disruption in Europe whilst state of the art measurements and ash dispersion forecasts were heavily criticized by the aviation industry. Here we demonstrate for the first time that large improvements can be made in quantitative predictions of the fate of volcanic ash emissions, by using an inversion scheme that couples a priori source information and the output of a Lagrangian dispersion model with satellite data to estimate the volcanic ash source strength as a function of altitude and time. From the inversion, we obtain a total fine ash emission of the eruption of 8.3 ± 4.2 Tg for particles in the size range of 2.8g-28 μm diameter. We evaluate the results of our model results with a posteriori ash emissions using independent ground-based, airborne and space-borne measurements both in case studies and statistically. Subsequently, we estimate the area over Europe affected by volcanic ash above certain concentration thresholds relevant for the aviation industry. We find that during three episodes in April and May, volcanic ash concentrations at some altitude in the atmosphere exceeded the limits for the "Normal" flying zone in up to 14 % (6g-16 %), 2 % (1g-3 %) and 7 % (4g-11 %), respectively, of the European area. For a limit of 2 mg mĝ̂'3 only two episodes with fractions of 1.5 % (0.2g-2.8 %) and 0.9 % (0.1g-1.6 %) occurred, while the current "No-Fly" zone criterion of 4 mg mg-3 was rarely exceeded. Our results have important ramifications for determining air space closures and for real-time quantitative estimations of ash concentrations. Furthermore, the general nature of our method yields better constraints on the distribution and fate of volcanic ash in the Earth system. © 2011 Author(s).
BibTeX:
@article{Stohl2011,
  author = {Stohl, A. and Prata, A.J. and Eckhardt, S. and Clarisse, L. and Durant, A. and Henne, S. and Kristiansen, N.I. and Minikin, A. and Schumann, U. and Seibert, P. and Stebel, K. and Thomas, H.E. and Thorsteinsson, T. and Tørseth, K. and Weinzierl, B.},
  title = {Determination of time-and height-resolved volcanic ash emissions and their use for quantitative ash dispersion modeling: The 2010 Eyjafjallajökull eruption},
  journal = {Atmospheric Chemistry and Physics},
  year = {2011},
  volume = {11},
  pages = {4333-4351},
  doi = {10.5194/acp-11-4333-2011}
}
Abstract: It is argued that whether the use of the Born--Oppenheimer approximation is thought to require consideration of the potential energy surface in the context of a full Coulomb Schrödinger Hamiltonian in which translational and rotational motions are explicitly considered, and then it is inconsistent to treat that surface without allowing for the rotational motion of the molecule. Some of the implications of this upon the calculation of partition functions are considered. © 2011 Springer-Verlag.
BibTeX:
@article{Sutcliffe2011,
  author = {Sutcliffe, B.T.},
  title = {An analysis of the role of the Born--Oppenheimer approximation in calculating rotational--vibrational interactions in molecules},
  journal = {Theoretical Chemistry Accounts},
  year = {2011},
  volume = {130},
  pages = {187-195},
  doi = {10.1007/s00214-011-0953-5}
}
BibTeX:
@article{Sutcliffe2011a,
  author = {Sutcliffe, B.T. and Woolley, R.G.},
  title = {A comment on "Editorial 37"},
  journal = {Foundations of Chemistry},
  year = {2011},
  volume = {13},
  pages = {93-95},
  doi = {10.1007/s10698-011-9110-4}
}
Abstract: A single band belonging to the Ã′2Δ- X̃2Σ+ band system has been rotationally analyzed for each of the two isotopologues, BaOH and BaOD, using high-resolution V-type optical-optical double resonance spectroscopy. BaOH and BaOD molecules were synthesized in a Broida-type oven. High-resolution spectra were recorded by monitoring the dip in fluorescence of the B2Σ+- X2Σ+ transition excited by a single-mode ring dye laser (pump laser), whilst a single-mode Ti:Sapphire laser scanned the corresponding Ã′2Δ-X̃2 Σ+ transition. The observed spectra resemble a typical 2Π-2Σ transition, believed to emanate from single or triple quanta of the bending vibration in the à ′2Δ state. Measured rotational lines have been assigned and rotational and fine structure parameters determined through a combined least-squares fit with the millimeter-wave pure rotational data of the X 2Σ+ state. Previous analyses of the Ã2Π-X̃2Σ+ transitions of BaOH and BaOD yielded significantly different spin-orbit coupling constants, which were attributed to possible global and local perturbations arising from vibrationally-excited bands of the A′2Δ state. Although the newly observed A′2Δ state bands have not been conclusively assigned a specific spin state, the derived Ω-doubling constants show significant 2Π1/2 character, further indicating strong interactions between the A2Π and A ′2Δ states of BaOH. To validate these conclusions, ab initio calculations have been carried out to further understand the nature of the BaOH excited states. The D̃′2Σ+, D̃2Σ+, C̃2Π, B̃2Σ+, Ã2Π, Ã′2Δ and X̃2Σ+ states have been characterized by means of multireference configuration interaction calculations using the MOLPRO software. Calculated vertical term energies show relatively good agreement with existing optical data. © 2011 Elsevier Inc. All rights reserved.
BibTeX:
@article{Tandy2011,
  author = {Tandy, J.D. and Wang, J.-G. and Liévin, J. and Bernath, P.F.},
  title = {Investigating the electronic states of BaOH by V-type double resonance spectroscopy and ab initio calculations: Further evidence of perturbation from the Ã′2Δ state},
  journal = {Journal of Molecular Spectroscopy},
  year = {2011},
  volume = {270},
  pages = {44-50},
  doi = {10.1016/j.jms.2011.08.009}
}
Abstract: To further our understanding of the effects of biomass burning emissions on atmospheric composition, we report measurements of trace species in biomass burning plumes made by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) instrument on the SCISAT-1 satellite. An extensive set of 15 molecules, C 2H 2, C 2H 6, CH 3OH, CH 4, CO, H 2CO, HCN, HCOOH, HNO 3, NO, NO 2, N 2O 5, O 3, OCS and SF6 are used in our analysis. Even though most biomass burning smoke is typically confined to the boundary layer, some of these emissions are injected directly into the free troposphere via fire-related convective processes and transported away from the emission source. Further knowledge of the aging of biomass burning emissions in the free troposphere is needed. Tracer-tracer correlations are made between known pyrogenic species in these plumes in an effort to characterize them and follow their chemical evolution. Criteria such as age and type of biomass material burned are considered. © 2011 Author(s).
BibTeX:
@article{Tereszchuk2011,
  author = {Tereszchuk, K.A. and González Abad, G. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F. and Bernath, P.F.},
  title = {ACE-FTS measurements of trace species in the characterization of biomass burning plumes},
  journal = {Atmospheric Chemistry and Physics},
  year = {2011},
  volume = {11},
  pages = {12169-12179},
  doi = {10.5194/acp-11-12169-2011}
}
Abstract: The v 1+v 3 band of 12Cv 2Hv 2 was recorded using a high resolution continuous scan Fourier transform interferometer fitted with a femto OPO absorption source. Various experimental schemes were successfully implemented, including multipass absorption in a cell and also in a supersonic expansion, and cavity enhanced absorption. An optimal rms noise equivalent absorption of 2.2×10 -9cm -1Hz 1/2 per spectral element was reached in the latter case, corresponding to α min=1.5×10 -7cm -1. Performances are illustrated and discussed. Copyright © 2011 Taylor and Francis Group, LLC.
BibTeX:
@article{Vaernewijck2011,
  author = {Vaernewijck, X.D.G.D. and Didriche, K. and Lauzin, C. and Rizopoulos, A. and Herman, M. and Kassi, S.},
  title = {Cavity enhanced FTIR spectroscopy using a femto OPO absorption source},
  journal = {Molecular Physics},
  year = {2011},
  volume = {109},
  pages = {2173-2179},
  doi = {10.1080/00268976.2011.602990}
}
Abstract: Amino-acid enantiomeric excesses (ee's) have been detected in different types of carbonaceous chondrites, all in favor of the L enantiomer. In this article, we discuss possible deterministic causes to the presence of these amino-acid ee's in meteorites and evaluate in particular enantioselective photolysis by circularly polarized light (CPL). The electronic circular dichroism spectra of a set of amino- and hydroxy-acids, all detected in chondritic matter but some with ee's and others without ee's, were calculated and compared. The spectra were calculated for the most stable conformation(s) of the considered molecules using quantum mechanical methods (density functional theory). Our results suggest that CPL photolysis in the gas phase was perhaps not at the origin of the presence of ee's in meteorites and that the search for another, but still unknown, deterministic cause must be seriously undertaken. © 2011 Wiley-Liss, Inc.
BibTeX:
@article{Vandenbussche2011,
  author = {Vandenbussche, S. and Reisse, J. and Bartik, K. and Lievin, J.},
  title = {The search for a deterministic origin for the presence of nonracemic amino-acids in meteorites: A computational approach},
  journal = {Chirality},
  year = {2011},
  volume = {23},
  pages = {367-373},
  doi = {10.1002/chir.20933}
}
Abstract: FIR spectra of C2H2 have been recorded at 0.00096 cm-1 spectral resolution using the Canadian Light Source synchrotron facility. The analysis allowed us to assign 731 new vibration-rotation lines from 48 bands in 12C2H2, 38 of which are reported for the first time. Two additional bands are assigned to 13CH12CH. The measured line positions and calculated spectra can be made available to help in the remote sensing of acetylene in the terahertz spectral range. © 2010 Elsevier B.V. All rights reserved.
BibTeX:
@article{Amyay2010,
  author = {Amyay, B. and Herman, M. and Fayt, A. and Fusina, L. and Predoi-Cross, A.},
  title = {High resolution FTIR investigation of 12C2H2 in the FIR spectral range using synchrotron radiation},
  journal = {Chemical Physics Letters},
  year = {2010},
  volume = {491},
  pages = {17-19},
  doi = {10.1016/j.cplett.2010.03.053}
}
Abstract: A new atsp2K module is presented for evaluating the electron density function of any multiconfiguration Hartree-Fock or configuration interaction wave function in the non-relativistic or relativistic Breit-Pauli approximation. It is first stressed that the density function is not a priori spherically symmetric in the general open shell case. Ways of building it as a spherical symmetric function are discussed, from which the radial electron density function emerges. This function is written in second quantized coupled tensorial form for exploring the atomic spherical symmetry. The calculation of its expectation value is performed using the angular momentum theory in orbital, spin, and quasispin spaces, adopting a generalized graphical technique. The natural orbitals are evaluated from the diagonalization of the density matrix. Program summary: Program title: DENSITY. Catalogue identifier: AEFR_v1_0. Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEFR_v1_0.html. Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland. Licensing provisions: Standard CPC license, http://cpc.cs.qub.ac.uk/licence/licence.html. No. of lines in distributed program, including test data, etc.: 6603. No. of bytes in distributed program, including test data, etc.: 169 881. Distribution format: tar.gz. Programming language: FORTRAN 90. Computer: HP XC Cluster Platform 4000. Operating system: HP XC System Software 3.2.1, which is a Linux distribution compatible with Red Hat Enterprise Advanced Server. Word size: 32 bits. Classification: 2.1, 2.9, 4.1. Subprograms used:A table is presented. Nature of problem: This program determines the atomic electronic density in the MCHF (LS) or Breit-Pauli (LS J) approximation. It also evaluates the natural orbitals by diagonalizing the density matrix. Solution method: Building the density operator using second quantization - spherical symmetry averaging - evaluating the matrix elements of the one-body excitation operators in the configuration state function (CSF) space using the angular momentum theory in orbital, spin, and quasispin spaces. Restrictions: Original restrictions from ATSP2K package, i.e. all orbitals within a wave function expansion are assumed to be orthonormal. Configuration states are restricted to at most eight subshells in addition to the closed shells common to all configuration states. The maximum size of the working arrays, related to the number of CSFs and active orbitals, is limited by the available memory and disk space. Unusual features: The programming style is essentially F77 with extensions for the POINTER data type and associated memory allocation. These have been available on workstations for more than a decade, but their implementations are compiler dependent. The present code has been installed and tested extensively using the Portland Group, pgf90, compiler. Running time: The calculation of the electron density for an n = 9 complete active space (CAS) MCHF wave function (271 733 CSFs - 45 orbitals) takes around 9 minutes on one AMD Opteron dual-core at 2.4 GHz CPU. References: [1]C. Froese Fischer, G. Tachiev, G. Gaigalas, M.R. Godefroid, An MCHF atomic-structure package for large-scale calculation, Comput. Phys. Commun. 176 (2007) 559-579. © 2009 Elsevier B.V. All rights reserved.
BibTeX:
@article{Borgoo2010,
  author = {Borgoo, A. and Scharf, O. and Gaigalas, G. and Godefroid, M.},
  title = {Multiconfiguration electron density function for the ATSP2K-package},
  journal = {Computer Physics Communications},
  year = {2010},
  volume = {181},
  pages = {426-439},
  doi = {10.1016/j.cpc.2009.10.014}
}
Abstract: As a tetrahedral molecule, methane has no permanent dipole moment. Its spectrum, however, displays faint absorption lines in the THz region, due to centrifugal distorsion effects. This is important for planetary applications since this region is used to measure methane concentration in some planetary atmospheres, in particular on Titan. Up to now, all measurements relied either on some old low resolution infrared absorption spectra, or on high resolution Stark measurements for low J values only. Even if these results have been reexamined recently [Wishnow EH, Orton GS, Ozier I, Gush HP. The distorsion dipole rotational spectrum of CH4: a low temperature far-infrared study. J Quant Spectrosc Radiat Transfer 2007;103:102-17], it seemed highly desirable to obtain much more precise laboratory data.The high-intensity synchrotron radiation, combined with a 151.75±0.1m optical path in a White cell and a Bruker IFS 125 HR FTIR spectrometer at the AILES beamline of SOLEIL, enabled us to record this very weak spectrum at high resolution for the first time. Spectra were obtained in the 50-500cm-1 wavenumber range at 296K and 9.91, 20, 50 and 100mbar with a resolution of 0.00074, 0.00134, 0.0034 and 0.0067cm-1 (FWHM of the sinc function), respectively. The rotational clusters are fully resolved and the good signal-to-noise ratio has enabled precise measurements of transition intensities (92 cold band lines and 96 Dyad-Dyad hot band lines, with normal abundance intensities in the range 2×10-26-1×10-24cm-1/(molcm-2)), yielding an accurate determination of the dipole moment derivatives. Such results should allow a better determination of CH4 concentration in planetary objects. © 2010 Elsevier Ltd.
BibTeX:
@article{Boudon2010,
  author = {Boudon, V. and Pirali, O. and Roy, P. and Brubach, J.-B. and Manceron, L. and Vander Auwera, J.},
  title = {The high-resolution far-infrared spectrum of methane at the SOLEIL synchrotron},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2010},
  volume = {111},
  pages = {1117-1129},
  doi = {10.1016/j.jqsrt.2010.02.006}
}
Abstract: We present a new method for measuring SO2 with the data from the ASTER (Advanced Spaceborne Thermal Emission and Reflectance radiometer) orbital sensor. The method consists of adjusting the SO2 column amount until the ratios of radiance simulated on several ASTER bands match the observations. We present a sensitivity analysis for this method, and two case studies. The sensitivity analysis shows that the selected band ratios depend much less on atmospheric humidity, sulfate aerosols, surface altitude and emissivity than the raw radiances. Measurements with &lt;25% relative precision are achieved, but only when the thermal contrast between the plume and the underlying surface is higher than 10K. For the case studies we focused on Miyakejima and Etna, two volcanoes where SO2 is measured regularly by COSPEC or scanning DOAS. The SO2 fluxes computed from a series of ten images of Miyakejima over the period 2000-2002 is in agreement with the long term trend of measurement for this volcano. On Etna, we compared SO2 column amounts measured by ASTER with those acquired simultaneously by ground-based automated scanning DOAS. The column amounts compare quite well, providing a more rigorous validation of the method. The SO2 maps retrieved with ASTER can provide quantitative insights into the 2D structure of non-eruptive volcanic plumes, their dispersion and their progressive depletion in SO2. © 2010 .
BibTeX:
@article{Campion2010,
  author = {Campion, R. and Salerno, G.G. and Coheur, P.-F. and Hurtmans, D. and Clarisse, L. and Kazahaya, K. and Burton, M. and Caltabiano, T. and Clerbaux, C. and Bernard, A.},
  title = {Measuring volcanic degassing of SO2 in the lower troposphere with ASTER band ratios},
  journal = {Journal of Volcanology and Geothermal Research},
  year = {2010},
  volume = {194},
  pages = {42-54},
  doi = {10.1016/j.jvolgeores.2010.04.010}
}
Abstract: The sulfur electron affinities eA(S) are measured by photodetachment microscopy for the two isotopes S32 and S34 (16752.9753(41) and 16752.9776(85) cm-1, respectively). The isotope shift in the electron affinity is found to be more probably positive, eA(S34)-eA(S32) =+0.0023(70) cm -1, but the uncertainty allows for the possibility that it may be either "normal" [eA(S34) eA(S32)] or "anomalous" [eA(S34) &lt;eA(S32)]. The isotope shift is estimated theoretically using elaborate correlation models, monitoring the electron affinity and the mass polarization term expectation value. The theoretical analysis predicts a very large specific mass shift (SMS) that counterbalances the normal mass shift (NMS) and produces an anomalous isotope shift eA(S34)-eA(S32) =-0.0053(24) cm-1, field shift corrections included. The total isotope shift can always be written as the sum of the NMS (here +0.0169 cm-1) and a residual isotope shift (RIS). Since the NMS has nearly no uncertainty, the comparison between experimental and theoretical RIS is more fair. With respective values of -0.0146(70) cm-1 and -0.0222(24) cm-1, these residual isotope shifts are found to agree within the estimated uncertainties. © 2010 The American Physical Society.
BibTeX:
@article{Carette2010,
  author = {Carette, T. and Drag, C. and Scharf, O. and Blondel, C. and Delsart, C. and Froese Fischer, C. and Godefroid, M.},
  title = {Isotope shift in the sulfur electron affinity: Observation and theory},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2010},
  volume = {81},
  article number = {042522},
  doi = {10.1103/PhysRevA.81.042522}
}
Abstract: The hyperfine constants of the levels 2p 2 (3P)3s 4P J, 2p 2 (3P)3p 4P o J and 2p 2 (3P)3p 4D o J, deduced by Jennerich et al. [Eur. Phys. J. D 40, 81 (2006)] from the observed hyperfine structures of the transitions 2p 2 (3P)3s 4P J→ 2p2 (3P)3p 4P o J and 2p 2 (3P)3s 4P J→ 2p 2 ( 3P)3p 4D o J recorded by saturation spectroscopy in the near-infrared, strongly disagree with the ab initio values of Jönsson et al. [J. Phys. B: At. Mol. Opt. Phys. 43, 115006 (2010)]. We propose a new interpretation of the recorded weak spectral lines. If the latter are indeed reinterpreted as crossover signals, a new set of experimental hyperfine constants is deduced, in very good agreement with the ab initio predictions. © 2010 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
BibTeX:
@article{Carette2010a,
  author = {Carette, T. and Nemouchi, M. and Jönsson, P. and Godefroid, M.},
  title = {Saturation spectra of low lying states of Nitrogen: Reconciling experiment with theory},
  journal = {European Physical Journal D},
  year = {2010},
  volume = {60},
  pages = {231-242},
  doi = {10.1140/epjd/e2010-00241-2}
}
Abstract: The unprotonated and protonated monoreduced forms of the polyazaaromatic Ru(II) coordination complexes [Ru(tap)3]2+ and [Ru(tap)2(phen)]2+ (tap = 1,4,5,8-tetraazaphenanthrene; phen = 1,10-phenanthroline), that is, [Ru(tap)3]•+, [Ru(tap)2(phen)]•+, [Ru(tap)2(tap-H)] •2+, and [Ru(tap)(tap-H)(phen)]•2+, were studied by Density Functional Theory (DFT). The electron spin density of these radical cations, the isotropic Fermi-contact, and the anisotropic dipolar contributions to the hyperfine coupling constants of the H nuclei were calculated in vacuo and using a continuum model for water solvation. For [Ru(tap)2(phen)] •+, as well as for its protonated form, the DFT results show that the unpaired electron is not localized on the phen ligand. For both [Ru(tap)3]•+ and [Ru(tap)2(phen)] •+, they reveal high electron spin density in the vicinity of tap H-2 and tap H-7 (the H atoms in the ortho position of the tap non-chelating N atoms). These results are in full agreement with recent steady-state 1H photo-Chemically Induced Dynamic Nuclear Polarization (photo-CIDNP) measurements. The DFT calculations performed for the protonated species also predict major 1H photo-CIDNP enhancements at these positions. Interestingly, they indicate significantly different polarization for tap H-9,10, suggesting that the occurrence of a photoinduced electron transfer with protonation of the reduced species might be detected by high-precision photo-CIDNP experiments. © 2010 American Chemical Society.
BibTeX:
@article{Cauet2010b,
  author = {Cauët, E. and Bogatko, S. and Mugeniwabagara, E. and Fusaro, L. and Kirsch-De Mesmaeker, A. and Luhmer, M. and Vaeck, N.},
  title = {Density functional theory interpretation of the 1H photo-chemically induced dynamic nuclear polarization enhancements characterizing photoreduced polyazaaromatic Ru(II) coordination complexes},
  journal = {Inorganic Chemistry},
  year = {2010},
  volume = {49},
  pages = {7826-7831},
  doi = {10.1021/ic100636j}
}
Abstract: Results of ab initio molecular dynamics (AIMD) simulations (density functional theory+PBE96) of the dynamics of waters in the hydration shells surrounding the Zn2+ ion (T≈300 K, ρ ≈1 gm/ cm3) are compared to simulations using a combined quantum and classical molecular dynamics [AIMD/molecular mechanical (MM)] approach. Both classes of simulations were performed with 64 solvating water molecules (∼15 ps) and used the same methods in the electronic structure calculation (plane-wave basis set, time steps, effective mass, etc.). In the AIMD/MM calculation, only six waters of hydration were included in the quantum mechanical (QM) region. The remaining 58 waters were treated with a published flexible water-water interaction potential. No reparametrization of the water-water potential was attempted. Additional AIMD/MM simulations were performed with 256 water molecules. The hydration structures predicted from the AIMD and AIMD/MM simulations are found to agree in detail with each other and with the structural results from x-ray data despite the very limited QM region in the AIMD/MM simulation. To further evaluate the agreement of these parameter-free simulations, predicted extended x-ray absorption fine structure (EXAFS) spectra were compared directly to the recently obtained EXAFS data and they agree in remarkable detail with the experimental observations. The first hydration shell contains six water molecules in a highly symmetric octahedral structure is (maximally located at 2.13-2.15 Å versus 2.072 Å EXAFS experiment). The widths of the peak of the simulated EXAFS spectra agree well with the data (8.4 Å2 versus 8.9 Å2 in experiment). Analysis of the H-bond structure of the hydration region shows that the second hydration shell is trigonally bound to the first shell water with a high degree of agreement between the AIMD and AIMD/MM calculations. Beyond the second shell, the bonding pattern returns to the tetrahedral structure of bulk water. The AIMD/MM results emphasize the importance of a quantum description of the first hydration shell to correctly describe the hydration region. In these calculations the full d10 electronic structure of the valence shell of the Zn2+ ion is retained. The simulations show substantial and complex charge relocation on both the Zn 2+ ion and the first hydration shell. The dipole moment of the waters in the first hydration shell is 3.4 D (3.3 D AIMD/MM) versus 2.73 D bulk. Little polarization is found for the waters in the second hydration shell (2.8 D). No exchanges were seen between the first and the second hydrations shells; however, many water transfers between the second hydration shell and the bulk were observed. For 64 waters, the AIMD and AIMD/MM simulations give nearly identical results for exchange dynamics. However, in the larger particle simulations (256 waters) there is a significant reduction in the second shell to bulk exchanges. © 2010 American Institute of Physics.
BibTeX:
@article{Cauet2010,
  author = {Cauët, E. and Bogatko, S. and Weare, J.H. and Fulton, J.L. and Schenter, G.K. and Bylaska, E.J.},
  title = {Structure and dynamics of the hydration shells of the Zn2+ ion from ab initio molecular dynamics and combined ab initio and classical molecular dynamics simulations},
  journal = {Journal of Chemical Physics},
  year = {2010},
  volume = {132},
  article number = {194502},
  doi = {10.1063/1.3421542}
}
Abstract: Vertical ionization potentials (IPs) of nucleobases embedded in a fully solvated DNA fragment (12-mer B-DNA fragment + 22 sodium counterions + 5760 water molecules equilibrated to 298 K) have been calculated using a combined quantum mechanical molecular mechanics (QM/MM) approach. Calculations of the vertical IP of the anion Cl- are reported that support the accuracy of the application of a QM/MM method to this problem. It is shown that the π nucleotide HOMO origin for the emitted electron is localized on the base by the hydration structure surrounding the DNA in a way similar to that recently observed for pyrimidine nucleotides in aqueous solutions (Slavícě k, P.; et al. J. Am. Chem. Soc. 2009, 131, 6460). In a first step, a high level of theory, CCSD(T)/aug-cc-pVDZ, was used to calculate the vertical IP of each of the four single bases isolated in the QM region while the remaining DNA fragment, counterions, and water solvent molecules were included in the MM region. The calculated vertical IPs show a large positive shift of 3.2-3.3 eV compared to the corresponding gas-phase values. This shift is similar for all four DNA bases. The origin of the large increase in vertical IPs of nucleobases is found to be the long-range electrostatic interactions with the solvation structure outside the DNA helix. Thermal fluctuations in the fluid can result in IP changes of roughly 1 eV on a picosecond time scale. IPs of π-stacked and H-bonded clusters of DNA bases were also calculated using the same QM/MM model but with a lower level of theory, B3LYP/6-31G(d=0.2). An IP shift of 4.02 eV relative to the gas phase is found for a four-base-pair B-DNA duplex configuration. The primary goal of this work was to estimate the influence of long-range solvation interactions on the ionization properties of DNA bases rather than provide highly precise IP evaluations. The QM/MM model presented in this work provides an attractive method to treat the difficult problem of incorporating a detailed long-range structural model of physiological conditions into investigations of the electronic processes in DNA. © 2010 American Chemical Society.
BibTeX:
@article{Cauet2010a,
  author = {Cauët, E. and Valiev, M. and Weare, J.H.},
  title = {Vertical ionization potentials of nucleobases in a fully solvated DNA environment},
  journal = {Journal of Physical Chemistry B},
  year = {2010},
  volume = {114},
  pages = {5886-5894},
  doi = {10.1021/jp9120723}
}
Abstract: We present a sophisticated radiative transfer code for modeling outgoing IR radiation from planetary atmospheres and, conversely, for retrieving atmospheric properties from high-resolution nadir-observed spectra. The forward model is built around a doubling-adding routine and calculates, in a spherical refractive geometry, the outgoing radiation emitted by the Earth and the atmosphere containing one layer of aerosol. The inverse model uses an optimal estimation approach and can simultaneously retrieve atmospheric trace gases, aerosol effective radius, and concentration. It is different from existing codes, as most forward codes dealing with multiple scattering assume a plane-parallel atmosphere, and as for the retrieval, it does not rely on precalculated spectra, the use of microwindows, or two-step retrievals. The simultaneous retrieval on a broad spectral range exploits the full potential of current state-of-the-art hyperspectral IR sounders, such as AIRS and IASI, and should be particularly useful in studying major pollution events. We present five example retrievals of IASI spectra observed in the range from 800 to 1200 cm-1 above dust, volcanic ash, sulfuric acid, ice particles, and biomass burning aerosols. © 2010 Optical Society of America.
BibTeX:
@article{Clarisse2010b,
  author = {Clarisse, L. and Hurtmans, D. and Prata, A.J. and Karagulian, F. and Clerbaux, C. and De Mazière, M. and Coheur, P.-F.},
  title = {Retrieving radius, concentration, optical depth, and mass of different types of aerosols from high-resolution infrared nadir spectra},
  journal = {Applied Optics},
  year = {2010},
  volume = {49},
  pages = {3713-3722},
  doi = {10.1364/AO.49.003713}
}
Abstract: Remote satellite detection of airborne volcanic ash is important for mitigating hazards to aviation and for calculating plume altitudes. Infrared sounders are essential for detecting ash, as they can distinguishing aerosol type and can be used day and night. While broadband sensors are mainly used for this purpose, they have inherent limitations. Typically, water and ice can mask volcanic ash, while wind blown dust can yield false detection. High spectral resolution sounders should be able to overcome some of these limitations. However, existing detection methods are not easily applicable to hyperspectral sounders and there is therefore a pressing need for novel techniques. In response, we propose a sensitive and robust volcanic ash detection method for hyperspectral sounders based on correlation coefficients and demonstrate it on IASI observations. We show that the method differentiates ash from clouds and dust. Easy to implement, it could contribute to operational volcanic hazard mitigation. © 2010 by the American Geophysical Union.
BibTeX:
@article{Clarisse2010a,
  author = {Clarisse, L. and Prata, F. and Lacour, J.-L. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {A correlation method for volcanic ash detection using hyperspectral infrared measurements},
  journal = {Geophysical Research Letters},
  year = {2010},
  volume = {37},
  article number = {L19806},
  doi = {10.1029/2010GL044828}
}
Abstract: [1] Atmospheric ammonia (NH3) has recently been observed with infrared sounders from space. Here we present 1 year of detailed bidaily satellite retrievals with the Infrared Atmospheric Sounding Interferometer and some retrievals of the Tropospheric Emission Spectrometer over the San Joaquin Valley, California, a highly polluted agricultural production region. Several sensitivity issues are discussed related to the sounding of ammonia, in terms of degrees of freedom, averaging kernels, and altitude of maximum sensitivity and in relation to thermal contrast and concentration. We also discuss their seasonal dependence and sources of errors. We demonstrate boundary layer sensitivity of infrared sounders when there is a large thermal contrast between the surface and the bottom of the atmosphere. For the San Joaquin Valley, large thermal contrast is the case for daytime measurements in spring, summer, and autumn and for nighttime measurements in autumn and winter when a large negative thermal contrast is amplified by temperature inversion. © 2010 by the American Geophysical Union.
BibTeX:
@article{Clarisse2010,
  author = {Clarisse, L. and Shephard, M.W. and Dentener, F. and Hurtmans, D. and Cady-Pereira, K. and Karagulian, F. and Van Damme, M. and Clerbaux, C. and Coheur, P.-F.},
  title = {Satellite monitoring of ammonia: A case study of the San Joaquin Valley},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2010},
  volume = {115},
  article number = {D13302},
  doi = {10.1029/2009JD013291}
}
Abstract: Atmospheric remote sensing from satellites is an essential component of the observational strategy deployed to monitor atmospheric pollution and changing composition. During this decade, remote sensors using the thermal infrared (TIR) spectral range have demonstrated their ability to sound the troposphere and provide global distribution for some of the key atmospheric species. This article illustrates three operational applications made possible with the IASI instrument onboard the European satellite MetOp, which opens new perspectives for routine observation of the evolution of atmospheric composition from space. © 2009 Académie des sciences.
BibTeX:
@article{Clerbaux2010,
  author = {Clerbaux, C. and Turquety, S. and Coheur, P.},
  title = {Infrared remote sensing of atmospheric composition and air quality: Towards operational applications},
  journal = {Comptes Rendus - Geoscience},
  year = {2010},
  volume = {342},
  pages = {349-356},
  doi = {10.1016/j.crte.2009.09.010}
}
Abstract: An improved set of molecular constants and term values are given for the X2Π (v = 0-5) state of the CH radical. They are derived from a fit of previously published data and additional lines taken from infrared solar spectra recorded on orbit and from new laboratory IR emission data. © 2010 Elsevier Inc. All rights reserved.
BibTeX:
@article{Colin2010,
  author = {Colin, R. and Bernath, P.F.},
  title = {Revised molecular constants and term values for the X2Π state of CH},
  journal = {Journal of Molecular Spectroscopy},
  year = {2010},
  volume = {263},
  pages = {120-122},
  doi = {10.1016/j.jms.2010.06.013}
}
BibTeX:
@article{DeNatale2010,
  author = {De Natale, P. and Di Lonardo, G. and Herman, M. and Quack, M. and Softley, T.},
  title = {Foreword: Twenty-first colloquium on high-resolution molecular spectroscopy},
  journal = {Molecular Physics},
  year = {2010},
  volume = {108},
  pages = {675-676},
  doi = {10.1080/00268971003798187}
}
Abstract: The prototype role of this simple four-atom molecule is highlighted in high-resolution vibration-rotation spectroscopy, intramolecular dynamics, and astrochemistry. © 2010 Elsevier B.V. All rights reserved.
BibTeX:
@article{Didriche2010,
  author = {Didriche, K. and Herman, M.},
  title = {A four-atom molecule at the forefront of spectroscopy, intramolecular dynamics and astrochemistry: Acetylene},
  journal = {Chemical Physics Letters},
  year = {2010},
  volume = {496},
  pages = {1-7},
  doi = {10.1016/j.cplett.2010.07.031}
}
Abstract: The experimental set-up FANTASIO, for 'Fourier trANsform, Tunable diode and quadrupole mAss spectrometers interfaced to a Supersonic expansIOn' (M. Herman, K. Didriche, D. Hurtmans, B. Kizil, P. Macko, A. Rizopoulos and P. Van Poucke, Mol. Phys. 105, 815 (2007)) built in Brussels has been updated. The turbomolecular pumping system of the supersonic expansion has been doubled and new mirrors, with reflectivity 99.999% instead of 99.99%, have been set in the CW-cavity ring down spectrometer probing jet-cooled molecules. The changes all together result in a signal to noise increased by up to a factor 10, around 1.5 μm. These improvements are demonstrated with various acetylene data in the 2CH excitation range, including the assignment of a new sub-band of acetylene-Ar, with K'-K'' = 2-3. The focus is set on the acetylene dimer. Overtone sub-bands, with b- and a-type structures, are identified for the first time in the literature. They are assigned to vibrational excitation in the hat and body units of the T shaped dimer, respectively. The relevance of the overtone data on acetylene dimers for space remote sensing is highlighted. © 2010 Taylor & Francis.
BibTeX:
@article{Didriche2010a,
  author = {Didriche, K. and Lauzin, C. and Foldes, T. and De Ghellinck, X.D.V. and Herman, M.},
  title = {The FANTASIO+ set-up to investigate jet-cooled molecules: Focus on overtone bands of the acetylene dimer},
  journal = {Molecular Physics},
  year = {2010},
  volume = {108},
  pages = {2155-2163},
  doi = {10.1080/00268976.2010.489525}
}
Abstract: Continuous wave cavity ring-down spectroscopy using an electronically switched telecom distributed feedback laser module is demonstrated. By adding a compensation waveform current to the step-function switched laser current the laser wavelength stabilisation time is reduced to about 4ms corresponding to a 200Hz utmost ring-down transient repetition rate. © 2010 The Institution of Engineering and Technology.
BibTeX:
@article{Foeldes2010,
  author = {Földes, T. and Čermák, P. and Rakovský, J. and MacKo, M. and Krištof, J. and Veis, P. and MacKo, P.},
  title = {Electronic DFB laser switching for continuous wave cavity ring-down spectroscopy},
  journal = {Electronics Letters},
  year = {2010},
  volume = {46},
  pages = {523-525},
  doi = {10.1049/el.2010.2360}
}
Abstract: High-spectral resolution infrared spectra of the earth's atmosphere and surface are routinely available from satellite sensors, such as the Atmospheric Infrared Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI). We exploit the spectral content of AIRS data to demonstrate that airborne volcanic ash has a unique signature in the infrared (8-12 μm) that can be used to infer particle size, infrared opacity and composition. The spectral signature is interpreted with the aid of a radiative transfer model utilizing the optical properties of andesite, rhyolite and quartz. Based on the infrared spectral signature, a new volcanic ash detection algorithm is proposed that can discriminate volcanic ash from other airborne substances and we show that the algorithm depends on particle size, optical depth and composition. The new algorithm has an improved sensitivity to optically thin ash clouds, and hence can detect them for longer (  4 days) and at greater distances from the source(  5000 km). © 2009 Elsevier Inc. All rights reserved.
BibTeX:
@article{Gangale2010,
  author = {Gangale, G. and Prata, A.J. and Clarisse, L.},
  title = {The infrared spectral signature of volcanic ash determined from high-spectral resolution satellite measurements},
  journal = {Remote Sensing of Environment},
  year = {2010},
  volume = {114},
  pages = {414-425},
  doi = {10.1016/j.rse.2009.09.007}
}
Abstract: In June 2009 the Sarychev volcano located in the Kuril Islands to the northeast of Japan erupted explosively, injecting ash and an estimated 1.2 0.2 Tg of sulfur dioxide into the upper troposphere and lower stratosphere, making it arguably one of the 10 largest stratospheric injections in the last 50 years. During the period immediately after the eruption, we show that the sulfur dioxide (SO2) cloud was clearly detected by retrievals developed for the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument and that the resultant stratospheric sulfate aerosol was detected by the Optical Spectrograph and Infrared Imaging System (OSIRIS) limb sounder and CALIPSO lidar. Additional surface-based instrumentation allows assessment of the impact of the eruption on the stratospheric aerosol optical depth. We use a nudged version of the HadGEM2 climate model to investigate how well this state-of-the-science climate model can replicate the distributions of SO 2 and sulfate aerosol. The model simulations and OSIRIS measurements suggest that in the Northern Hemisphere the stratospheric aerosol optical depth was enhanced by around a factor of 3 (0.01 at 550 nm), with resultant impacts upon the radiation budget. The simulations indicate that, in the Northern Hemisphere for July 2009, the magnitude of the mean radiative impact from the volcanic aerosols is more than 60% of the direct radiative forcing of all anthropogenic aerosols put together. While the cooling induced by the eruption will likely not be detectable in the observational record, the combination of modeling and measurements would provide an ideal framework for simulating future larger volcanic eruptions. Copyright 2010 by the American Geophysical Union.
BibTeX:
@article{Haywood2010,
  author = {Haywood, J.M. and Jones, A. and Clarisse, L. and Bourassa, A. and Barnes, J. and Telford, P. and Bellouin, N. and Boucher, O. and Agnew, P. and Clerbaux, C. and Coheur, P. and Degenstein, D. and Braesicke, P.},
  title = {Observations of the eruption of the Sarychev volcano and simulations using the HadGEM2 climate model},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2010},
  volume = {115},
  article number = {D21212},
  doi = {10.1029/2010JD014447}
}
BibTeX:
@article{Herman2010,
  author = {Herman, M. and Saykally, R.J.},
  title = {Special issue devoted to molecular complexes in our atmosphere and beyond},
  journal = {Molecular Physics},
  year = {2010},
  volume = {108},
  pages = {2153},
  doi = {10.1080/00268976.2010.506048}
}
Abstract: Hyperfine structure parameters are calculated for the 2p2( 3P)3s 4PJ, 2p2(3P)3p 4Po J and 2p2(3P)3p 4Do J levels, using the ab initio multiconfiguration Hartree-Fock method. The theoretical hyperfine coupling constants are in complete disagreement with the experimental values of Jennerich et al deduced from the analysis of the near-infrared Doppler-free saturated absorption spectra. © 2010 IOP Publishing Ltd.
BibTeX:
@article{Joensson2010,
  author = {Jönsson, P. and Carette, T. and Nemouchi, M. and Godefroid, M.},
  title = {Ab initio calculations of 14N and 15N hyperfine structures},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2010},
  volume = {43},
  article number = {115006},
  doi = {10.1088/0953-4075/43/11/115006}
}
Abstract: In this work we use infrared spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI) to characterize the emissions from the Mount Kasatochi volcanic eruption on 7 and 8 August 2008. We first derive the total atmospheric load of sulfur dioxide (SO2) and its evolution over time. For the initial plume, we found values over 1.7 Tg Of SO2, making it the largest eruption since the 1991 eruptions of Pinatubo and Hudson. Vertical profiles were retrieved using a line-by-line radiative transfer model and an inversion procedure based on the optimal estimation method (OEM). For the Kasatochi eruption, we found a plume altitude of 12.5 ± 4 km. Taking advantage of IASI's broad spectral coverage, we used the v3 band (∼ 1362 cm-1) and, for the first time, the v1 + v 3 band (∼2500 cm-1) of SO2 for the retrievals. While the v3 band saturates easily for high SO 2 concentrations, preventing accurate retrieval, the v1 + v3 band has a much higher saturation threshold. We also analyzed the broadband signature observed in the radiance spectra in the 1072-1215 cm -1 range associated with the presence of aerosols. In the initial volcanic plume the signature matches closely that of mineral ash, while by 10 August most mineral ash is undetectable, and the extinction is shown to match closely the absorption spectrum of liquid H2SO4 drops. The extinction by sulphuric acid particles was confirmed by comparing spectra before and a month after the eruption, providing the first spectral detection of such aerosols from nadir view radiance data. Copyright 2010 by the American Geophysical Union.
BibTeX:
@article{Karagulian2010,
  author = {Karagulian, F. and Clarisse, L. and Clerbaux, C. and Prata, A.J. and Hurtmans, D. and Coheur, P.F.},
  title = {Detection of volcanic SO2, ash, and H2SO4 using the infrared atmospheric sounding interferometer (IASI)},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2010},
  volume = {115},
  article number = {D00L02},
  doi = {10.1029/2009JD012786}
}
Abstract: A proof of principle experiment was performed by recording the cavity enhanced absorption spectrum of the weak b-X transition of molecular oxygen in the atmosphere using a Ti:Sa femtosecond laser as an absorption source and a high resolution continuous scan Fourier transform interferometer. The cavity was mode matched and either continuously scanned or stabilized at the so-called magic point. An optimal rms noise equivalent absorption of 3 × 10-7 cm-1 Hz-1/2 was reached in the latter case, corresponding to αmin = 3 × 10-7 cm-1. © 2009 Elsevier B.V. All rights reserved.
BibTeX:
@article{Kassi2010,
  author = {Kassi, S. and Didriche, K. and Lauzin, C. and de Ghellinck d'Elseghem Vaernewijckb, X. and Rizopoulos, A. and Herman, M.},
  title = {Demonstration of cavity enhanced FTIR spectroscopy using a femtosecond laser absorption source},
  journal = {Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy},
  year = {2010},
  volume = {75},
  pages = {142-145},
  doi = {10.1016/j.saa.2009.09.058}
}
BibTeX:
@article{Keim2010,
  author = {Keim, C. and Eremenko, M. and Orphal, J. and Dufour, G. and Flaud, J.-M. and Höpfner, M. and Boynard, A. and Clerbaux, C. and Payan, S. and Coheur, P.-F. and Hurtmans, D. and Claude, H. and De Backer, H. and Dier, H. and Johnson, B. and Kelder, H. and Kivi, R. and Koide, T. and López Bartolomé, M. and Lambkin, K. and Moore, D. and Schmidlin, F.J. and Stübi, R.},
  title = {Erratum: Tropospheric ozone from IASI: Comparison of different inversion algorithms and validation with ozone sondes in the northern middle latitudes (Atmospheric Chemistry and Physics (2009) 9 (9329-9347) DOI: 10.5194/acp-9-9329-2009)},
  journal = {Atmospheric Chemistry and Physics},
  year = {2010},
  volume = {10},
  pages = {6345},
  doi = {10.5194/acp-10-6345-2010}
}
Abstract: Using the quantum chemistry package MOLPRO and an adapted basis set, we have calculated the adiabatic potential energy curves of the first 20 1Σ+, 19 3Σ+, 12 1Π, 9 3Π, 4 1Δ and 2 3Δ electronic states of the HeH+ molecular ion in CASSCF and CI approaches. The results are compared with previous works. The radial and rotational non-adiabatic coupling matrix elements as well as the dipole moments are also calculated. The asymptotic behaviour of the potential energy curves and of the various couplings between the states is also studied. Using the radial couplings, the diabatic representation is defined and we present an example of our diabatization procedure on the 1Σ + states. © 2010 IOP Publishing Ltd.
BibTeX:
@article{Loreau2010,
  author = {Loreau, J. and Liévin, J. and Palmeri, P. and Quinet, P. and Vaeck, N.},
  title = {Ab initio calculation of the 66 low-lying electronic states of HeH +: Adiabatic and diabatic representations},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2010},
  volume = {43},
  article number = {065101},
  doi = {10.1088/0953-4075/43/6/065101}
}
Abstract: The first metastable triplet state of HeH+ was found to be present in ion beam experiments, with its lifetime estimated to be between hundreds of milliseconds and thousand of seconds. In this work, we use ab initio methods to evaluate the radiative lifetimes of the six vibrational levels of the a 3∑+ of HeH+. The transition a 3∑+ → X1∑+ is spin-forbidden, but acquires intensity through spin-orbit interaction with the singlet and triplet Π states. Large scale CASSCF/MRCI calculations using an adapted basis set were performed to determine the potential energy curves of the relevant states of HeH+ as well as the matrix elements of the dipole and spin-orbit operators. The wave functions and energies of the vibrational levels of the a3∑+ and X1∑+ states are obtained using a B-spline method and compared to previous works. We find that the radiative lifetime of the vibrational levels increases strongly with v, the lifetime of the v=0 state being 150 s. We also analyze the contributions from discrete and continuum parts of the spectrum. With such a long lifetime, the a3∑+ state could have astrophysical implications. © 2010 American Institute of Physics.
BibTeX:
@article{Loreau2010a,
  author = {Loreau, J. and Lívin, J. and Vaeck, N.},
  title = {Radiative lifetime of the a 3∑+ + state of HeH+ from ab initio calculations},
  journal = {Journal of Chemical Physics},
  year = {2010},
  volume = {133},
  article number = {114302},
  doi = {10.1063/1.3481782}
}
Abstract: The charge-transfer in low-energy (0.25 to 150eV/amu) H(nl)+He +(1s) collisions is investigated using a quasimolecular approach for the n=2,3 as well as the first two n=4 singlet states. The diabatic potential energy curves of the HeH+ molecular ion are obtained from the adiabatic potential energy curves and the nonadiabatic radial coupling matrix elements using a two-by-two diabatization method, and a time-dependent wave-packet approach is used to calculate the state-to-state cross sections. We find a strong dependence of the charge-transfer cross section on the principal and orbital quantum numbers n and l of the initial or final state. We estimate the effect of the nonadiabatic rotational couplings, which is found to be important even at energies below 1eV/amu. However, the effect is small on the total cross sections at energies below 10eV/amu. We observe that to calculate charge-transfer cross sections in an n manifold, it is only necessary to include states with n′≤n, and we discuss the limitations of our approach as the number of states increases. © 2010 The American Physical Society.
BibTeX:
@article{Loreau2010b,
  author = {Loreau, J. and Sodoga, K. and Lauvergnat, D. and Desouter-Lecomte, M. and Vaeck, N.},
  title = {Ab initio calculation of H+He+ charge-transfer cross sections for plasma physics},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2010},
  volume = {82},
  article number = {012708},
  doi = {10.1103/PhysRevA.82.012708}
}
Abstract: Ethylene (ethene, H2C=CH2) is a naturally occurring compound in ambient air that affects atmospheric chemistry and global climate. The C2H4 spectrum is available in databases only for the 1000 and 3000cm-1 ranges. In this work, the ethylene absorption spectrum was measured in the 6030-6250cm-1 range with the use of a high resolution Bruker IFS 125HR Fourier-spectrometer and a two-channel opto-acoustic spectrometer with a diode laser. As a secondary standard of wavelengths, the methane absorption spectrum was used in both cases.A preliminary analysis was realized thanks to the tensorial formalism developed by the Dijon group that is implemented in the XTDS software package [39]. We considered the two combination bands ν5+ν9 and ν5+ν11 as an interacting dyad. Parameters for the ν9/ν11 dyad were fitted simultaneously from a re-analysis of previously recorded supersonic expansion jet FTIR data, while parameters for the v5=1 Raman level were taken from literature. More than 600 lines could be assigned in the 6030-6250cm-1 region (and also 682 in the 2950-3150cm-1 region) and effective Hamiltonian parameters were fitted, including Coriolis interaction parameters. The dyad features are globally quite well reproduced, even if there are still problems at high J values. © 2010 Elsevier Ltd.
BibTeX:
@article{LoronoGonzalez2010,
  author = {Loroño Gonzalez, M.A. and Boudon, V. and Loëte, M. and Rotger, M. and Bourgeois, M.-T. and Didriche, K. and Herman, M. and Kapitanov, V.A. and Ponomarev, Y. and Solodov, A.A. and Solodov, A.M. and Petrova, T.M.},
  title = {High-resolution spectroscopy and preliminary global analysis of C-H stretching vibrations of C2H4 in the 3000 and 6000cm-1 regions},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2010},
  volume = {111},
  pages = {2265-2278},
  doi = {10.1016/j.jqsrt.2010.04.010}
}
Abstract: We study the interconversion of multipartite symmetric N-qubit states under stochastic local operations and classical communication (SLOCC). We demonstrate that if two symmetric states can be connected with a nonsymmetric invertible local operation (ILO), then they belong necessarily to the separable, W, or Greenberger-Horne-Zeilinger (GHZ) entanglement class, establishing a practical method of discriminating subsets of entanglement classes. Furthermore, we prove that there always exists a symmetric ILO connecting any pair of symmetric N-qubit states equivalent under SLOCC, simplifying the requirements for experimental implementations of local interconversion of those states. © 2010 The American Physical Society.
BibTeX:
@article{Mathonet2010,
  author = {Mathonet, P. and Krins, S. and Godefroid, M. and Lamata, L. and Solano, E. and Bastin, T.},
  title = {Entanglement equivalence of N-qubit symmetric states},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2010},
  volume = {81},
  article number = {052315},
  doi = {10.1103/PhysRevA.81.052315}
}
Abstract: Absorption spectra of HDO/D2O mixtures recorded in the 5600-8800cm-1 region with a total pressure of water from 13 up to 18hPa and an absorption path length of 600m have been analyzed in order to obtain new spectroscopic data for HD18O and D2 18O. In spite of the low natural 18O concentration (about 2×10-3 with respect to the 16O one), about 1100 transitions belonging to HD18O and more than 280 transitions belonging to D2 18O have been assigned. Most of the D2 18O transitions belong to the v1+v2+v3 and 2v1+v3 bands. Sets of energy levels for seven vibrational states of D2 18O and four states of HD18O are reported for the first time. The comparison of the experimental data with the calculated values based on Partridge-Schwenke global variational calculations is discussed. © 2010 Elsevier Ltd.
BibTeX:
@article{Mikhailenko2010,
  author = {Mikhailenko, S.N. and Tashkun, S.A. and Daumont, L. and Jenouvrier, A. and Carleer, M. and Fally, S. and Vandaele, A.C.},
  title = {Line positions and energy levels of the 18O substitutions from the HDO/D2O spectra between 5600 and 8800cm-1},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2010},
  volume = {111},
  pages = {2185-2196},
  doi = {10.1016/j.jqsrt.2010.01.028}
}
Abstract: The link between energy-resolved spectra and time-resolved dynamics is explored quantitatively for acetylene (12C2H2), X̃1Σ+g with up to 8600 cm -1 of vibrational energy. This comparison is based on the extensive and reliable knowledge of the vibration-rotation energy levels and on the model Hamiltonian used to fit them to high precision [B. Amyay, S. Robert, M. Herman, A. Fayt, B. Raghavendra, A. Moudens, J. Thiévin, B. Rowe, and R. Georges, J. Chem. Phys. 131, 114301 (2009)]. Simulated intensity borrowing features in high resolution absorption spectra and predicted survival probabilities in intramolecular vibrational redistribution (IVR) are first investigated for the v4 + v5 and v3 bright states, for J = 2, 30 and 100. The dependence of the results on the rotational quantum number and on the choice of vibrational bright state reflects the interplay of three kinds of off-diagonal resonances: anharmonic, rotational l-type, and Coriolis. The dynamical quantities used to characterize the calculated time-dependent dynamics are the dilution factor φd, the IVR lifetime τIVR, and the recurrence time τrec. For the two bright states v3 + 2v4 and 7v4, the collisionless dynamics for thermally averaged rotational distributions at T = 27, 270 and 500 K were calculated from the available spectroscopic data. For the 7v4 bright state, an apparent irreversible decay of is found. In all cases, the model Hamiltonian allows a detailed calculation of the energy flow among all of the coupled zeroth-order vibration-rotation states. © 2010 Taylor &amp; Francis.
BibTeX:
@article{Perry2010,
  author = {Perry, D.S. and Miller, A. and Amyay, B. and Fayt, A. and Herman, M.},
  title = {Vibration-rotation alchemy in acetylene (12C2H 2), X̃1Σ+g at low vibrational excitation: From high resolution spectroscopy to fast intramolecular dynamics},
  journal = {Molecular Physics},
  year = {2010},
  volume = {108},
  pages = {1115-1132},
  doi = {10.1080/00268971003660874}
}
Abstract: In this paper, we provide a detailed comparison between carbon monoxide (CO) data measured by the Infrared Atmospheric Sounding Interferometer (IASI)/MetOp and aircraft observations over the Arctic. The CO measurements were obtained during North American (NASA ARCTAS and NOAA ARCPAC) and European campaigns (POLARCAT-France, POLARCAT-GRACE and YAK-AEROSIB) as part of the International Polar Year (IPY) POLARCAT activity in spring and summer 2008. During the campaigns different air masses were sampled including clean air, polluted plumes originating from anthropogenic sources in Europe, Asia and North America, and forest fire plumes originating from Siberia and Canada. The paper illustrates that CO-rich plumes following different transport pathways were well captured by the IASI instrument, in particular due to the high spatial coverage of IASI. The comparison between IASI CO total columns, 0ĝ€"5 km partial columns and profiles with collocated aircraft data was achieved by taking into account the different sensitivity and geometry of the sounding instruments. A detailed analysis is provided and the agreement is discussed in terms of information content and surface properties at the location of the observations. For profiles, the data were found to be in good agreement in spring with differences lower than 17%, whereas in summer the difference can reach 20% for IASI profiles below 8 km for polluted cases. For total columns the correlation coefficients ranged from 0.15 to 0.74 (from 0.47 to 0.77 for partial columns) in spring and from 0.26 to 0.84 (from 0.66 to 0.88 for partial columns) in summer. A better agreement is seen over the sea in spring (0.73 for total column and 0.78 for partial column) and over the land in summer (0.69 for total columns and 0.81 for partial columns). The IASI vertical sensitivity was better over land than over sea, and better over land than over sea ice and snow allowing a higher potential to detect CO vertical distribution during summer. © 2010 Author(s).
BibTeX:
@article{Pommier2010,
  author = {Pommier, M. and Law, K.S. and Clerbaux, C. and Turquety, S. and Hurtmans, D. and Hadji-Lazaro, J. and Coheur, P.-F. and Schlager, H. and Ancellet, G. and Paris, J.-D. and Néd́lec, P. and Diskin, G.S. and Podolske, J.R. and Holloway, J.S. and Bernath, P.},
  title = {IASI carbon monoxide validation over the Arctic during POLARCAT spring and summer campaigns},
  journal = {Atmospheric Chemistry and Physics},
  year = {2010},
  volume = {10},
  pages = {10655-10678},
  doi = {10.5194/acp-10-10655-2010}
}
Abstract: Ash particles and sulfur dioxide gas are two significant components of volcanic clouds that are important because of their effects on the atmosphere. Several different satellite instruments are capable of delivering quantitative measurements of ash and SO2, but few can provide simultaneous assessments. High-spectral resolution (ν/Δν ∼ 1200) infrared satellite data from the Atmospheric Infrared Sounder (AIRS) are utilized to detect volcanic ash within the 8-12 μm window region, and at the same time exploit the 4.0 μm and 7.3 μm bands of SO2 to detect SO 2 at two different heights. The purpose is to study the interaction between gas and particles in dispersing volcanic clouds, and investigate the circumstances when the gas-rich and ash-rich parts of the plume are collocated and when they separate. Simultaneous retrievals of ash and SO2 in the eruption clouds from Okmok and Kasatochi suggest that the two components were transported together for at least the first 3 days after the initial injection. Later (several days) transport is difficult to infer because of the lack of sensitivity of the ash algorithm to thin, dispersing ash clouds. For Kasatochi and Okmok, AIRS measured maximum masses of approximately 1.21 ± 0.01 Tg and 0.29 ± 0.01 Tg of SO2, and 0.31 ± 0.03 Tg and 0.07 ±0.03 Tg of fine ash (1 μm < radii < 10 μm), respectively. The retrieval schemes described here are capable of detecting the distribution of SO2 simultaneously with estimates of ash concentrations from the same satellite instrument and represent an important improvement for observations of multispecies dispersing volcanic clouds. Analyses of other volcanic eruptions show that SO2 and ash do not always travel together. Consequently, it is concluded that for dispersing volcanic clouds it is vital to be able to detect both SO2-rich and ash-rich clouds simultaneously in order to diagnose their effect on the atmosphere and the aviation hazard. © 2010 by the American Geophysical Union.
BibTeX:
@article{Prata2010,
  author = {Prata, A.J. and Gangale, G. and Clarisse, L. and Karagulian, F.},
  title = {Ash and sulfur dioxide in the 2008 eruptions of Okmok and Kasatochi: Insights from high spectral resolution satellite measurements},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2010},
  volume = {115},
  article number = {D00L18},
  doi = {10.1029/2009JD013556}
}
Abstract: The v4 band of 1,1,1-trifluoroethane (CH3CF3) has been studied using synchrotron radiation at the far-infrared beamline, Canadian Light Source. The spectra were recorded at a resolution of 0.00096 cm-1 in the spectral range 800 to 860 cm-1 using a Bruker IFS125 FT spectrometer. Altogether 2785 lines were assigned to qPK(J) and qRK(J) transitions with J″ up to 71 and K up to 45. The qQK(J) sub-branches are too congested and overlapped to other hot-band Q branches to be analysed. A Watson-type Hamiltonian containing the usual terms up to the 6th power in the angular momentum operators was used in the analysis. The spectroscopic parameters obtained from the fit reproduce 2636 transitions with a standard deviation of about 0.00016 cm-1. © 2010 Taylor &amp; Francis.
BibTeX:
@article{Predoi-Cross2010a,
  author = {Predoi-Cross, A. and Ibrahim, A. and Herman, M. and Fusina, L. and Nivellini, G. and Di Lonardo, G.},
  title = {The high resolution infrared spectrum of the v4 band of 1,1,1-trifluoroethane},
  journal = {Molecular Physics},
  year = {2010},
  volume = {108},
  pages = {2303-2307},
  doi = {10.1080/00268971003720322}
}
Abstract: Using a Fourier transform spectrometer setup we have measured the self-broadened half width, pressure shift, and line asymmetry coefficients for transitions in the 30012←00001 and 30013←00001 vibrational bands of carbon dioxide for four different temperatures. A total of 46 pure CO2 spectra were recorded at 0.008 and 0.009cm-1 resolution and at pressures varying from a few Torr to nearly an atmosphere. The individual spectral line profiles have been fitted by a Voigt profile and a speed-dependent Voigt profile, to which we have added dispersion profiles to account for weak line mixing. A comparison of the sets of results obtained for each band showed no vibrational dependence of the broadening coefficients. The self-broadening and self-shift coefficients are compared to semiclassical calculations based on the Robert-Bonamy formalism and were found to be in good agreement. The line asymmetry results are compared to line mixing calculations based on the Energy Corrected Sudden (ECS) and Exponential Power Gap models. © 2010 Elsevier Ltd.
BibTeX:
@article{Predoi-Cross2010,
  author = {Predoi-Cross, A. and Liu, W. and Murphy, R. and Povey, C. and Gamache, R.R. and Laraia, A.L. and McKellar, A.R.W. and Hurtmans, D.R. and Malathy Devi, V.},
  title = {Measurement and computations for temperature dependences of self-broadened carbon dioxide transitions in the 30012←00001 and 30013←00001 bands},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2010},
  volume = {111},
  pages = {1065-1079},
  doi = {10.1016/j.jqsrt.2010.01.003}
}
Abstract: An examination is made of how the nuclear motion Hamiltonian arises from a consideration of solutions to the eigenvalue problem for the full Coulomb Hamiltonian and the role played by the usual clamped-nuclei electronic Hamiltonian in the construction of such solutions. © 2009 Springer-Verlag.
BibTeX:
@article{Sutcliffe2010,
  author = {Sutcliffe, B.},
  title = {To what question is the clamped-nuclei electronic potential the answer?},
  journal = {Theoretical Chemistry Accounts},
  year = {2010},
  volume = {127},
  pages = {121-131},
  doi = {10.1007/s00214-009-0594-0}
}
Abstract: Multiconfiguration expansions frequently target valence correlation and correlation between valence electrons and the outermost core electrons. Correlation within the core is often neglected. A large orbital basis is needed to saturate both the valence and core-valence correlation effects. This in turn leads to huge numbers of configuration state functions (CSFs), many of which are unimportant. To avoid the problems inherent to the use of a single common orthonormal orbital basis for all correlation effects in the multiconfiguration Hartree-Fock (MCHF) method, we propose to optimize independent MCHF pair-correlation functions (PCFs), bringing their own orthonormal one-electron basis. Each PCF is generated by allowing single- and double-excitations from a multireference (MR) function. This computational scheme has the advantage of using targeted and optimally localized orbital sets for each PCF. These pair-correlation functions are coupled together and with each component of the MR space through a low dimension generalized eigenvalue problem. Nonorthogonal orbital sets being involved, the interaction and overlap matrices are built using biorthonormal transformation of the coupled basis sets followed by a counter-transformation of the PCF expansions. Applied to the ground state of beryllium, the new method gives total energies that are lower than the ones from traditional complete active space (CAS)-MCHF calculations using large orbital active sets. It is fair to say that we now have the possibility to account for, in a balanced way, correlation deep down in the atomic core in variational calculations. © 2010 IOP Publishing Ltd.
BibTeX:
@article{Verdebout2010,
  author = {Verdebout, S. and Jönsson, P. and Gaigalas, G. and Godefroid, M. and Fischer, C.F.},
  title = {Exploring biorthonormal transformations of pair-correlation functions in atomic structure variational calculations},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2010},
  volume = {43},
  article number = {074017},
  doi = {10.1088/0953-4075/43/7/074017}
}
Abstract: This paper reports on daytime total vertical column abundances of formic acid (HCOOH) above the Northern mid-latitude, high altitude Jungfraujoch station (Switzerland; 46.5° N, 8.0° E, 3580 m alt.). The columns were derived from the analysis of infrared solar observations regularly performed with high spectral resolution Fourier transform spectrometers during over 1500 days between September 1985 and September 2007. The investigation was based on the spectrometric fitting of five spectral intervals, one encompassing the HCOOH &amp;nu;6 band Q branch at 1105 cm-1, and four additional ones allowing to optimally account for critical temperature-sensitive or time-evolving interferences by other atmospheric gases, in particular HDO, CCl2F2 and CHClF2. The main results derived from the 22 years long database indicate that the free tropospheric burden of HCOOH above the Jungfraujoch undergoes important short-term daytime variability, diurnal and seasonal modulations, inter-annual anomalies, but no significant long-term background change. A major progress in the remote determination of the atmospheric HCOOH columns reported here has resulted from the adoption of new, improved absolute spectral line intensities for the infrared &amp;nu;6 band of trans-formic acid, resulting in retrieved free tropospheric loadings being about a factor two smaller than if derived with previous spectroscopic parameters. Implications of this significant change with regard to earlier remote measurements of atmospheric formic acid and comparison with relevant Northern mid-latitude findings, both in situ and remote, will be assessed critically. Sparse HCOOH model predictions will also be evoked and assessed with respect to findings reported here. © 2010 Author(s).
BibTeX:
@article{Zander2010,
  author = {Zander, R. and Duchatelet, P. and Mahieu, E. and Demoulin, P. and Roland, G. and Servais, C. and Auwera, J.V. and Perrin, A. and Rinsland, C.P. and Crutzen, P.J.},
  title = {Formic acid above the Jungfraujoch during 1985-2007: Observed variability, seasonality, but no long-term background evolution},
  journal = {Atmospheric Chemistry and Physics},
  year = {2010},
  volume = {10},
  pages = {10047-10065},
  doi = {10.5194/acp-10-10047-2010}
}
Abstract: A high temperature source has been developed and coupled to a high resolution Fourier transform spectrometer to record emission spectra of acetylene around 3 μm up to 1455 K under Doppler limited resolution (0.015 cm-1). The ν3-ground state (GS) and ν2+ν4+ν5(∑u + and Δu)-GS bands and 76 related hot bands, counting e and f parities separately, are assigned using semiautomatic methods based on a global model to reproduce all related vibration-rotation states. Significantly higher J -values than previously reported are observed for 40 known substates while 37 new e or f vibrational substates, up to about 6000 cm-1, are identified and characterized by vibration-rotation parameters. The 3 811 new or improved data resulting from the analysis are merged into the database presented by Robert [Mol. Phys. 106, 2581 (2008)], now including 15 562 lines accessing vibrational states up to 8600 cm-1. A global model, updated as compared to the one in the previous paper, allows all lines in the database to be simultaneously fitted, successfully. The updates are discussed taking into account, in particular, the systematic inclusion of Coriolis interaction. © 2009 American Institute of Physics.
BibTeX:
@article{Amyay2009,
  author = {Amyay, B. and Robert, S. and Herman, M. and Fayt, A. and Raghavendra, B. and Moudens, A. and Thívin, J. and Rowe, B. and Georges, R.},
  title = {Vibration-rotation pattern in acetylene. II. Introduction of Coriolis coupling in the global model and analysis of emission spectra of hot acetylene around 3 μm},
  journal = {Journal of Chemical Physics},
  year = {2009},
  volume = {131},
  article number = {114301},
  doi = {10.1063/1.3200928}
}
Abstract: The variability and origin of the Coloured Dissolved Organic Matter (CDOM) were studied in the Belgian coastal and adjacent areas including offshore waters and the Scheldt estuary, through the parameters: absorption at 375 nm, aCDOM(375), and the slope of the absorption curve, S. aCDOM(375) varied between 0.20 and 1.31 m-1 and between 0.97 and 4.30 m-1 in the marine area and Scheldt estuary, respectively. S fluctuated between 0.0101 and 0.0203 nm-1 in the marine area and between 0.0167 and 0.0191 nm-1 in the Scheldt estuary. The comparative analysis of aCDOM(375) and S variations evidenced different origins of CDOM in the BCZ. The Scheldt estuarine waters showed decreasing aCDOM(375) values with increasing salinity but constant S value of ∼0.018 nm-1 suggesting a dominant terrestrial origin of CDOM. On the contrary, samples collected in the marine domain showed a narrow range of aCDOM(375) but highly variable S suggesting the additional presence of autochthonous sources of CDOM. This source was evidenced based on the sorting of the marine offshore data according to the stage of the phytoplankton bloom when they were collected. A clear distinction was made between CDOM released during the growth stage characterized by high S (∼0.017 nm-1) and low aCDOM(375) and the decay phase characterized by low S (∼0.013 nm-1) and high aCDOM(375). This observation was supported by CDOM measurements performed on pure phytoplankton cultures which showed increased CDOM release along the wax and wane of the bloom but decreasing S. We concluded that the high variability of the CDOM signature in offshore waters is explained by the local biological production and processing of CDOM. © 2009 Elsevier Ltd. All rights reserved.
BibTeX:
@article{Astoreca2009a,
  author = {Astoreca, R. and Rousseau, V. and Lancelot, C.},
  title = {Coloured dissolved organic matter (CDOM) in Southern North Sea waters: Optical characterization and possible origin},
  journal = {Estuarine, Coastal and Shelf Science},
  year = {2009},
  volume = {85},
  pages = {633-640},
  doi = {10.1016/j.ecss.2009.10.010}
}
Abstract: While mapping algal blooms from space is now well-established, mapping undesirable algal blooms in eutrophicated coastal waters raises further challenge in detecting individual phytoplankton species. In this paper, an algorithm is developed and tested for detecting Phaeocystis globosa blooms in the Southern North Sea. For this purpose, we first measured the light absorption properties of two phytoplankton groups, P. globosa and diatoms, in laboratory-controlled experiments. The main spectral difference between both groups was observed at 467 nm due to the absorption of the pigment chlorophyll c3 only present in P. globosa, suggesting that the absorption at 467 nm can be used to detect this alga in the field. A Phaeocystis-detection algorithm is proposed to retrieve chlorophyll c3 using either total absorption or water-leaving reflectance field data. Application of this algorithm to absorption and reflectance data from Phaeocystis-dominated natural communities shows positive results. Comparison with pigment concentrations and cell counts suggests that the algorithm can flag the presence of P. globosa and provide quantitative information above a chlorophyll c3 threshold of 0.3 mg m -3 equivalent to a P. globosa cell density of 3 × 10 6 cells L-1. Finally, the possibility of extrapolating this information to remote sensing reflectance data in these turbid waters is evaluated. © 2008 The Author(s).
BibTeX:
@article{Astoreca2009,
  author = {Astoreca, R. and Rousseau, V. and Ruddick, K. and Knechciak, C. and Van Mol, B. and Parent, J.-Y. and Lancelot, C.},
  title = {Development and application of an algorithm for detecting Phaeocystis globosa blooms in the Case 2 Southern North Sea waters},
  journal = {Journal of Plankton Research},
  year = {2009},
  volume = {31},
  pages = {287-300},
  doi = {10.1093/plankt/fbn116}
}
Abstract: We solve the entanglement classification under stochastic local operations and classical communication (SLOCC) for all multipartite symmetric states in the general N-qubit case. For this purpose, we introduce 2 parameters playing a crucial role, namely, the diversity degree and the degeneracy configuration of a symmetric state. Those parameters give rise to a simple method of identifying operational families of SLOCC entanglement classes of all symmetric N-qubit states, where the number of families grows as the partition function of the number of qubits. © 2009 The American Physical Society.
BibTeX:
@article{Bastin2009,
  author = {Bastin, T. and Krins, S. and Mathonet, P. and Godefroid, M. and Lamata, L. and Solano, E.},
  title = {Operational families of entanglement classes for symmetric N-qubit states},
  journal = {Physical Review Letters},
  year = {2009},
  volume = {103},
  article number = {070503},
  doi = {10.1103/PhysRevLett.103.070503}
}
Abstract: An improved set of molecular constants and term values are given for the X2Π (v = 0-13) and B2Σ+ (v = 0 and 1) states of the OH radical. They are derived from a fit of previously published laboratory data and additional lines taken from infrared solar spectra recorded on orbit. © 2009 Elsevier Inc. All rights reserved.
BibTeX:
@article{Bernath2009,
  author = {Bernath, P.F. and Colin, R.},
  title = {Revised molecular constants and term values for the X2Π and B2Σ+ states of OH},
  journal = {Journal of Molecular Spectroscopy},
  year = {2009},
  volume = {257},
  pages = {20-23},
  doi = {10.1016/j.jms.2009.06.003}
}
Abstract: The N2-broadening coefficients of ethane for 15 lines in the ν9 band at five pressures of nitrogen were measured. The measurements were carried out with a 1-m base White-type cell adjusted for four transits, yielding an optical path of 4.17 m. The average values of the N2-broadening coefficients obtained at 296 K from the Voigt and Rautian line shapes are respectively equal to 0.0822 and 0.0864 cm-1 atm-1. The results derived from the Voigt profile are 2 10% lower than those derived from the Rautian model. No rotational dependence is observed over the limited range of rotational quantum numbers investigated. The results also show that the adjustment of the Rautian profile provides an additional parameter, the collisional narrowing coefficient β0.
BibTeX:
@article{Blanquet2009,
  author = {Blanquet, G. and Auwera, J.V. and Lepère, M.},
  title = {N2-broadening coefficients of ethane},
  journal = {Journal of Molecular Spectroscopy},
  year = {2009},
  volume = {255},
  pages = {72-74},
  doi = {10.1016/j.jms.2009.02.020}
}
Abstract: In this paper, we present measurements of total and tropospheric ozone, retrieved from infrared radiance spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI), which was launched on board the MetOp-A European satellite in October 2006. We compare IASI total ozone columns to Global Ozone Monitoring Experiment-2 (GOME-2) observations and groundbased measurements from the Dobson and Brewer network for one full year of observations (2008). The IASI total ozone columns are shown to be in good agreement with both GOME-2 and ground-based data, with correlation coefficients of about 0.9 and 0.85, respectively. On average, IASI ozone retrievals exhibit a positive bias of about 9DU (3.3%) compared to both GOME-2 and ground-based measurements. In addition to total ozone columns, the good spectral resolution of IASI enables the retrieval of tropospheric ozone concentrations. Comparisons of IASI tropospheric columns to 490 collocated ozone soundings available from several stations around the globe have been performed for the period of June 2007-August 2008. IASI tropospheric ozone columns compare well with sonde observations, with correlation coefficients of 0.95 and 0.77 for the [surface-6 km] and [surface-12 km] partial columns, respectively. IASI retrievals tend to overestimate the tropospheric ozone columns in comparison with ozonesonde measurements. Positive average biases of 0.15DU (1.2%) and 3DU (11%) are found for the [surface-6 km] and for the [surface-12 km] partial columns respectively. © 2009 Author(s).
BibTeX:
@article{Boynard2009,
  author = {Boynard, A. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Turquety, S. and George, M. and Hadji-Lazaro, J. and Keim, C. and Meyer-Arnek, J.},
  title = {Measurements of total and tropospheric ozone from IASI: Comparison with correlative satellite, ground-based and ozonesonde observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {6255-6271}
}
Abstract: The charge transfer process in an ionized stacking of two consecutive guanines (G5'G3')+ has been studied by means of state-averaged CASSCF/MRCI and RASSCF/RASPT2 calculations. The ground and two first excited states of the radical cation have been characterized, and the topology of the corresponding potential energy surfaces (PESs) has been studied as a function of all intermolecular geometrical parameters. The results demonstrate that the charge transfer process in (G5'G 3')- is governed by the avoiding crossing between the ground and first excited states of the complex. Relative translation motions of both guanines in their molecular planes are shown to lead to the charge migration between G5' and G3'. Five stationary points (three minima and two saddle points) have been characterized along the reaction path describing the passage of the positive charge from G5' to G 3'. The global minimum on the PES is found to correspond to the charge configuration G5'+G3'. The existence of an intermediate minimum along the reaction path has been established, characterizing a structure where the positive charge is equally distributed between the two guanines. The calculated energy profile allowed us to determine the height of the potential energy barrier (7.33 kcal/mol) and to evaluate the electronic coupling at a geometry close to the avoiding crossing (3.6 kcal/mol). Test calculations showed that the topology of the ground state PES of the complex GG+ is qualitatively conserved upon optimization of the intramolecular geometrical parameters of the stationary points. © 2009 American Chemical Society.
BibTeX:
@article{Caueet2009,
  author = {Cauëet, E. and Liévin, J.},
  title = {Ab initio study of the electron transfer in an ionized stacked complex of guanines},
  journal = {Journal of Physical Chemistry A},
  year = {2009},
  volume = {113},
  pages = {9881-9890},
  doi = {10.1021/jp902426p}
}
Abstract: Global ammonia emissions have more than doubled since pre-industrial times, largely owing to agricultural intensification and widespread fertilizer use1. In the atmosphere, ammonia accelerates particulate matter formation, thereby reducing air quality. When deposited in nitrogen-limited ecosystems, ammonia can act as a fertilizer. This can lead to biodiversity reductions in terrestrial ecosystems, and algal blooms in aqueous environments2-8. Despite its ecological significance, there are large uncertainties in the magnitude of ammonia emissions, mainly owing to a paucity of ground-based observations and a virtual absence of atmospheric measurements3,8-11. Here we use infrared spectra, obtained by the IASI/MetOp satellite, to map global ammonia concentrations from space over the course of 2008. We identify several ammonia hotspots in middle-low latitudes across the globe. In general, we find a good qualitative agreement between our satellite measurements and simulations made using a global atmospheric chemistry transport model. However, the satellite data reveal substantially higher concentrations of ammonia north of 30° N, compared with model projections. We conclude that ammonia emissions could have been significantly underestimated in the Northern Hemisphere, and suggest that satellite monitoring of ammonia from space will improve our understanding of the global nitrogen cycle. © 2009 Macmillan Publishers Limited. All rights reserved.
BibTeX:
@article{Clarisse2009,
  author = {Clarisse, L. and Clerbaux, C. and Dentener, F. and Hurtmans, D. and Coheur, P.-F.},
  title = {Global ammonia distribution derived from infrared satellite observations},
  journal = {Nature Geoscience},
  year = {2009},
  volume = {2},
  pages = {479-483},
  doi = {10.1038/ngeo551}
}
Abstract: Atmospheric remote sounding from satellites is an essential component of the observational strategy deployed to monitor atmospheric pollution and changing composition. The IASI nadir looking thermal infrared sounder onboard MetOp will provide 15 years of global scale observations for a series of key atmospheric species, with unprecedented spatial sampling and coverage. This paper gives an overview of the instrument's capability for measuring atmospheric composition in the perspective of chemistry and air quality. The assessment is made in terms of species, accuracy and vertical information. Global distributions are presented for CO, CH4, O3 (total and tropospheric), HNO3, NH3, and volcanic SO2. Local distributions of organic species measured during fire events, such as C2H4, CH3OH, HCOOH, and PAN are also shown. For each species or process, the link is made to specialized papers in this issue. © 2009 Author(s).
BibTeX:
@article{Clerbaux2009,
  author = {Clerbaux, C. and Boynard, A. and Clarisse, L. and George, M. and Hadji-Lazaro, J. and Herbin, H. and Hurtmans, D. and Pommier, M. and Razavi, A. and Turquety, S. and Wespes, C. and Coheur, P.-F.},
  title = {Monitoring of atmospheric composition using the thermal infrared IASI/MetOp sounder},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {6041-6054}
}
Abstract: This work presents observations of a series of short-lived species in biomass burning plumes from the Infrared Atmospheric Sounding Interferometer (IASI), launched onboard the MetOp-A platform in October 2006. The strong fires that have occurred in the Mediterranean Basin - and particularly Greece - in August 2007, and those in Southern Siberia and Eastern Mongolia in the early spring of 2008 are selected to support the analyses. We show that the IASI infrared spectra in these fire plumes contain distinctive signatures of ammonia (NH3), ethene (C2H4), methanol (CH 3OH) and formic acid (HCOOH) in the atmospheric window between 800 and 1200 cm-1, with some noticeable differences between the plumes. Peroxyacetyl nitrate (CH3COOONO2, abbreviated as PAN) was also observed with good confidence in some plumes and a tentative assignment of a broadband absorption spectral feature to acetic acid (CH3COOH) is made. For several of these species these are the first reported measurements made from space in nadir geometry. The IASI measurements are analyzed for plume height and concentration distributions of NH3, C2H 4 and CH3OH. The Greek fires are studied in greater detail for the days associated with the largest emissions. In addition to providing information on the spatial extent of the plume, the IASI retrievals allow an estimate of the total mass emissions for NH3, C2H 4 and CH3OH. Enhancement ratios are calculated for the latter relative to carbon monoxide (CO), giving insight in the chemical processes occurring during the transport, the first day after the emission.
BibTeX:
@article{Coheur2009,
  author = {Coheur, P.-F. and Clarisse, L. and Turquety, S. and Hurtmans, D. and Clerbaux, C.},
  title = {IASI measurements of reactive trace species in biomass burning plumes},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {5655-5667}
}
Abstract: A slit nozzle supersonic expansion containing C2H2 (246 sccm) and N2O (355 sccm) seeded into Ar (1260 sccm) is investigated using CW cavity ring-down spectroscopy, in the 1.5 μm range. The C2H2-N2O van der Waals complex is observed around the 2CH acetylenic band. Despite strong perturbations, 117 b-type lines are assigned. Their combined fit with published microwave data leads to new upper state and improved lower state rotational constants. The Lorentzian width of the assigned line profiles sets the mean lifetime to 1.6 ns. The rotational temperature is estimated to be 15 K from the comparison between observed and simulated spectra. © 2008 Elsevier B.V. All rights reserved.
BibTeX:
@article{Didriche2009,
  author = {Didriche, K. and Lauzin, C. and Macko, P. and Herman, M. and Lafferty, W.J.},
  title = {Observation of the C2H2-N2O van der Waals complex in the overtone range using CW-CRDS},
  journal = {Chemical Physics Letters},
  year = {2009},
  volume = {469},
  pages = {35-37},
  doi = {10.1016/j.cplett.2008.12.037}
}
Abstract: New measurements of the absorption cross sections of gaseous benzene, toluene, meta-, ortho-, and para-xylene have been performed with a Fourier transform spectrometer Bruker IFS120 M at the resolution of 1 cm-1 over the 30 000-42 000 cm-1 spectral range. The recordings were carried out under different pressure and temperature conditions with pure samples. The effect of the temperature on the absorption cross sections is investigated. Comparison with the literature shows large differences, largely attributed to the experimental difficulties encountered during these previous measurements and to a resolution effect. To our knowledge, it is the first time that such a dataset of UV absorption cross sections with temperature dependence is reported in the literature. Such data should be useful for upcoming remote sensing applications, such as atmospheric studies both on Earth and on other planets. © 2008 Elsevier Ltd. All rights reserved.
BibTeX:
@article{Fally2009,
  author = {Fally, S. and Carleer, M. and Vandaele, A.C.},
  title = {UV Fourier transform absorption cross sections of benzene, toluene, meta-, ortho-, and para-xylene},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2009},
  volume = {110},
  pages = {766-782},
  doi = {10.1016/j.jqsrt.2008.11.014}
}
Abstract: The absorption spectrum of the (1-0) band of the b1 Σg + ← a1 Δg Noxon system near 1505 nm has been recorded by cw-CRDS in afterglow of a microwave discharge. The details of this method are presented along with spectroscopic data of 29 recorded lines of which 21 have been observed for the first time. The measured line positions are compared with positions calculated from rotational constants available in the literature. The density and the temperature of the generated singlet molecular oxygen O2 (a1 Δg) are presented. © 2008 Elsevier B.V. All rights reserved.
BibTeX:
@article{Foeldes2009,
  author = {Földes, T. and Čermák, P. and Macko, M. and Veis, P. and Macko, P.},
  title = {Cavity ring-down spectroscopy of singlet oxygen generated in microwave plasma},
  journal = {Chemical Physics Letters},
  year = {2009},
  volume = {467},
  pages = {233-236},
  doi = {10.1016/j.cplett.2008.11.040}
}
Abstract: Between July and November 2008, simultaneous observations were conducted by several orbiting instruments that monitor carbon monoxide in the atmosphere, among them the Infrared Atmospheric Sounding Instrument (IASI) and Measurements Of Pollution In The Troposphere (MOPITT). In this paper, the concentration retrievals at about 700 hPa from these two instruments are successively used in a variational Bayesian system to infer the global distribution of CO emissions. Starting from a global emission budget of 479 Tg for the considered period, the posterior estimate of CO emissions using IASI retrievals gives a total of 643 Tg, which is in close agreement with the budget calculated with version 3 of the MOPITT data (649 Tg). The regional totals are also broadly consistent between the two inversions. Even though our theoretical error budget indicates that IASI constrains the emissions slightly less than MOPITT, because of lesser sensitivity in the lower troposphere, these first results indicate that IASI may play a major role in the quantification of the emissions of CO.
BibTeX:
@article{Fortems-Cheiney2009,
  author = {Fortems-Cheiney, A. and Chevallier, F. and Pison, I. and Bousquet, P. and Carouge, C. and Clerbaux, C. and Coheur, P.-F. and George, M. and Hurtmans, D. and Szopa, S.},
  title = {On the capability of IASI measurements to inform about CO surface emissions},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {8735-8743}
}
Abstract: The Infrared Atmospheric Sounding Interferometer (IASI) onboard the MetOp satellite measures carbon monoxide (CO) on a global scale, twice a day. CO total columns and vertical profiles are retrieved in near real time from the nadir radiance spectra measured by the instrument in the thermal infrared (TIR) spectral range. This paper describes the measurement vertical sensitivity and provides a first assessment of the capabilities of IASI to measure CO distributions. On the global scale, 0.8 to 2.4 independent pieces of information are available for the retrieval. At mid latitudes, the information ranges between 1.5 and 2, which enables the lower and upper troposphere to be distinguished, especially when thermal contrast is significant. Global distributions of column CO are evaluated with correlative observations available from other nadir looking TIR missions currently in operation: the Measurements of Pollution in the Troposphere (MOPITT) onboard TERRA, the Atmospheric Infrared Sounder (AIRS) onboard AQUA and the Tropospheric Emission Spectrometer (TES) onboard AURA. The IASI CO columns are compared with MOPITT, AIRS and TES CO columns, adjusted with the a priori, for three different months: August 2008, November 2008 and February 2009. On average, total column discrepancies of about 7% are found between IASI and the three other sounders in the Northern Hemisphere and in the equatorial region. However when strong CO concentrations are present, such as during fire events, these discrepancies can climb as high as 17%. Instrument specifications of IASI versus other missions are also discussed.
BibTeX:
@article{George2009,
  author = {George, M. and Clerbaux, C. and Hurtmans, D. and Turquety, S. and Coheur, P.-F. and Pommier, M. and Hadji-Lazaro, J. and Edwards, D.P. and Worden, H. and Luo, M. and Rinsland, C. and McMillan, W.},
  title = {Carbon monoxide distributions from the IASI/METOP mission: Evaluation with other space-borne remote sensors},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {8317-8330}
}
Abstract: This work reports the first measurements of ethene (C2H 4) distributions in the upper troposphere. These are obtained by retrieving vertical profiles from 5 to 20 km infrared solar occultation spectra recorded in 2005 and 2006 by the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS). Background volume mixing ratios (vmrs) ranging from a few to about 50 pptv (10-12) are measured at the different altitudes, while for certain occultations, vmrs as high as 200 pptv are observed. Zonal distributions and vertically resolved latitudinal distributions are derived for the two year period analyzed, highlighting spatial -including a North-South gradient- as well as seasonal variations. We show the latter to be more pronounced at the highest latitudes, presumably as a result less active photochemistry during winter. The observation of C2H4 enhancements in remote Arctic regions at high latitudes is consistent with the occurrence fast transport processes of gaseous pollution from the continents leading to Arctic haze. © 2009.
BibTeX:
@article{Herbin2009,
  author = {Herbin, H. and Hurtmans, D. and Clarisse, L. and Turquety, S. and Clerbaux, C. and Rinsland, C.P. and Boone, C. and Bernath, P.F. and Coheur, P.-F.},
  title = {Distributions and seasonal variations of tropospheric ethene (C 2H4) from Atmospheric Chemistry Experiment (ACE-FTS) solar occupation spectra},
  journal = {Geophysical Research Letters},
  year = {2009},
  volume = {36},
  article number = {L04801},
  doi = {10.1029/2008GL036338}
}
Abstract: In this paper we analyze distributions of water vapour isotopologues in the troposphere using infrared spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI), which operates onboard the Metop satellite in nadir geometry. The simultaneous uncorrelated retrievals of H2 16O and HDO are performed on radiance measurements using a line-by-line radiative transfer model and an inversion procedure based on the Optimal Estimation Method (OEM). The characterizations of the retrieved products in terms of vertical sensitivity and error budgets show that IASI measurements contain up to 6 independent pieces of information on the vertical distribution of H216O and up to 3.5 for HDO from the surface up to the upper troposphere (0-20 km). Although the purpose of the paper is not validation, a restricted comparison with sonde measurements shows that the retrieved H216O profiles capture the seasonal/latitudinal variations of the water content, with good accuracy in the lowest layer but with larger uncertainties higher in the free and upper troposphere. Our results then demonstrate the ability of the IASI instrument to monitor atmospheric isotopologic water vapour distributions and to provide information on the partitioning of HDO as compared to H216O. The derivation of the δD is challenging and associated with large errors in the uncorrelated retrieval approach chosen here. As a result averaging on the vertical to produce a column-averaged δD is required to produce meaningful results for geophysical interpretation. As a case study, we analyse concentration distributions and spatio-temporal variations of H2 16O and δD during the October 2007 Krosa super-typhoon over South-East Asia. We show that individual δD have uncertainties of 37&amp;permil; for the vertically averaged values. Using the latter, we suggest that the typhoon produces a so-called amount-effect, where the δD is negatively correlated to the water amounts as a result of intense depletion of the deuterated species.
BibTeX:
@article{Herbin2009a,
  author = {Herbin, H. and Hurtmans, D. and Clerbaux, C. and Clarisse, L. and Coheur, P.-F.},
  title = {H216O and HDO measurements with IASI/MetOp},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {9433-9447}
}
Abstract: High resolution measurements of room temperature absorption with a controlled tunable diode laser (TDL) spectrometer have been made for R(2) and P(14) lines in the HCl fundamental band perturbed by N2, Xe, Ar and He at pressures lower than one atmosphere. Pressure broadening, shift and collisional narrowing parameters have been extracted by least-squares fitting of several collisional profiles to the spectra. Asymmetries are observed for P(14) broadened by Xe at the lowest pressures and attributed to correlations between velocity- and phase-changing collisions. © 2009 Elsevier Inc. All rights reserved.
BibTeX:
@article{Hurtmans2009,
  author = {Hurtmans, D. and Henry, A. and Valentin, A. and Boulet, C.},
  title = {Narrowing broadening and shifting parameters for R(2) and P(14) lines in the HCl fundamental band perturbed by N2 and rare gases from tunable diode laser spectroscopy},
  journal = {Journal of Molecular Spectroscopy},
  year = {2009},
  volume = {254},
  pages = {126-136},
  doi = {10.1016/j.jms.2009.01.015}
}
Abstract: In the northern Gulf of Eilat (Aqaba), sharp increases in the biomass of diatoms and rates of primary production occurred in April 2008. Within 24 h, diatom abundance rose from 8 Ã- 103 to 228 Ã- 10 3 cells l-1, and photosynthetic rates concomitantly doubled from 15 to 35 μg C l-1 d-1. Water transparency declined, as indicated by the vertical diffusion attenuation coefficient K d for photosynthetically active radiation (PAR), which increased from 0.076 to 0.090 m-1 and decreased the euphotic depth from 60 to 45 m. During this time, a significant increase in silica deposition by the diatoms was also detected. We attribute the mentioned changes in environmental characteristics to wind-generated surface currents. Strong winds (up to 10 m s-1) during the measurements enriched the surface layers with unusually high nutrient concentrations within.
BibTeX:
@article{Iluz2009,
  author = {Iluz, D. and Dishon, G. and Capuzzo, E. and Meeder, E. and Astoreca, R. and Montecino, V. and Znachor, P. and Ediger, D. and Marra, J.},
  title = {Short-term variability in primary productivity during a wind-driven diatom bloom in the Gulf of Eilat (Aqaba)},
  journal = {Aquatic Microbial Ecology},
  year = {2009},
  volume = {56},
  pages = {205-215},
  doi = {10.3354/ame01321}
}
Abstract: This paper presents a first statistical validation of tropospheric ozone products derived from measurements of the IASI satellite instrument. Since the end of 2006, IASI (Infrared Atmospheric Sounding Interferometer) aboard the polar orbiter Metop-A measures infrared spectra of the Earth's atmosphere in nadir geometry. This validation covers the northern mid-latitudes and the period from July 2007 to August 2008. Retrieval results from four different sources are presented: three are from scientific products (LATMOS, LISA, LPMAA) and the fourth one is the pre-operational product distributed by EUMETSAT (version 4.2). The different products are derived from different algorithms with different approaches. The difference and their implications for the retrieved products are discussed. In order to evaluate the quality and the performance of each product, comparisons with the vertical ozone concentration profiles measured by balloon sondes are performed and lead to estimates of the systematic and random errors in the IASI ozone products (profiles and partial columns). A first comparison is performed on the given profiles; a second comparison takes into account the altitude dependent sensitivity of the retrievals. Tropospheric columnar amounts are compared to the sonde for a lower tropospheric column (surface to about 6 km) and a total tropospheric column (surface to about 11 km). On average both tropospheric columns have small biases for the scientific products, less than 2 Dobson Units (DU) for the lower troposphere and less than 1 DU for the total troposphere. The comparison of the still pre-operational EUMETSAT columns shows higher mean differences of about 5 DU.
BibTeX:
@article{Keim2009,
  author = {Keim, C. and Eremenko, M. and Orphal, J. and Dufour, G. and Flaud, J.-M. and Höpfner, M. and Boynard, A. and Clerbaux, C. and Payan, S. and Coheur, P.-F. and Hurtmans, D. and Claude, H. and Dier, H. and Johnson, B. and Kelder, H. and Kivi, R. and Koide, T. and Bartolomé, M.L. and Lambkin, K. and Moore, D. and Schmidlin, F.J. and Stübi, R.},
  title = {Tropospheric ozone from IASI: Comparison of different inversion algorithms and validation with ozone sondes in the northern middle latitudes},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {9329-9347}
}
Abstract: Scientific findings from the last decades have clearly highlighted the need for a more comprehensive approach to atmospheric change processes. In fact, observation of atmospheric composition variables has been an important activity of atmospheric research that has developed instrumental tools (advanced analytical techniques) and platforms (instrumented passenger aircrafts, ground-based in situ and remote sensing stations, earth observation satellite instruments) providing essential information on the composition of the atmosphere. The variability of the atmospheric system and the extreme complexity of the atmospheric cycles for short-lived gaseous and aerosol species have led to the development of complex models to interpret observations, test our theoretical understanding of atmospheric chemistry and predict future atmospheric composition. The validation of numerical models requires accurate information concerning the variability of atmospheric composition for targeted species via comparison with observations and measurements. In this paper, we provide an overview of recent advances in instrumentation and methodologies for measuring atmospheric composition changes from space, aircraft and the surface as well as recent improvements in laboratory techniques that permitted scientific advance in the field of atmospheric chemistry. Emphasis is given to the most promising and innovative technologies that will become operational in the near future to improve knowledge of atmospheric composition. Our current observation capacity, however, is not satisfactory to understand and predict future atmospheric composition changes, in relation to predicted climate warming. Based on the limitation of the current European observing system, we address the major gaps in a second part of the paper to explain why further developments in current observation strategies are still needed to strengthen and optimise an observing system not only capable of responding to the requirements of atmospheric services but also to newly open scientific questions. © 2009 Elsevier Ltd. All rights reserved.
BibTeX:
@article{Laj2009,
  author = {Laj, P. and Klausen, J. and Bilde, M. and Plaß-Duelmer, C. and Pappalardo, G. and Clerbaux, C. and Baltensperger, U. and Hjorth, J. and Simpson, D. and Reimann, S. and Coheur, P.-F. and Richter, A. and De Mazière, M. and Rudich, Y. and McFiggans, G. and Torseth, K. and Wiedensohler, A. and Morin, S. and Schulz, M. and Allan, J.D. and Attié, J.-L. and Barnes, I. and Birmili, W. and Cammas, J.P. and Dommen, J. and Dorn, H.-P. and Fowler, D. and Fuzzi, S. and Glasius, M. and Granier, C. and Hermann, M. and Isaksen, I.S.A. and Kinne, S. and Koren, I. and Madonna, F. and Maione, M. and Massling, A. and Moehler, O. and Mona, L. and Monks, P.S. and Müller, D. and Müller, T. and Orphal, J. and Peuch, V.-H. and Stratmann, F. and Tanré, D. and Tyndall, G. and Abo Riziq, A. and Van Roozendael, M. and Villani, P. and Wehner, B. and Wex, H. and Zardini, A.A.},
  title = {Measuring atmospheric composition change},
  journal = {Atmospheric Environment},
  year = {2009},
  volume = {43},
  pages = {5351-5414},
  doi = {10.1016/j.atmosenv.2009.08.020}
}
Abstract: A quantitative characterization of the Rydberg and valence singlet electronic states of acetylene lying in the 5-10.7 eV region is performed by using large-scale ab initio calculations. A special attention is paid on the comparison between the present calculations and Mulliken's concepts for Rydberg states, based on singleelectron and single-configuration description. Most of the properties of the Rydberg states have been qualitatively understood via this comparison, mainly shown by the shape and size of the outer Rydberg molecular orbital. More quantitatively, Rydberg-valence mixing has been evaluated in several excited energy regions, as for instance, the interaction between the C̃ ' (1πg)2 1Ag doubly excited valence state and the manifold of electronic components of the np series, or the interaction between the Ẽ 1πg 1Bu valence state and the F̃ 3dπg 1σu+ Rydberg state. The rapid predissociation of the lowest C̃ 3só 1.u Rydberg state has been interpreted as a case of Rydbergization, earlier predicted by Mulliken. © 2009 American Chemical Society.
BibTeX:
@article{Laruelle2009,
  author = {Laruelle, F. and Boyé-Péronne, S. and Gauyacq, D. and Liévin, J.},
  title = {Revisiting mulliken's concepts about rydberg states and rydberg-valence interactions from large-scale ab initio calculations on the acetylene molecule},
  journal = {Journal of Physical Chemistry A},
  year = {2009},
  volume = {113},
  pages = {13210-13220},
  doi = {10.1021/jp903948k}
}
Abstract: A slit nozzle supersonic expansion containing acetylene [492 SCCM (SCCM denotes cubic centimeter per minute at STP)] and carbon dioxide (740 SCCM) seeded into Ar (837 SCCM) is investigated using cw-cavity ring-down spectroscopy, in the 1.5 μm range. The C2 H2 - CO 2 van der Waals complex is observed around the v1 + v 3 acetylenic band. The rotational temperature is estimated to be close to 60 K from the comparison between observed and simulated spectra. The analysis of the main, perturbed B -type band centered near 6 549.280 cm -1, is performed. It is attributed to a dimer with the known planar, C2v geometry. The present overtone data, involving ground state levels with higher J/K states (J≤35 and Ka≤ 20) than previously reported, are combined to 3 μm data [D. G. Prichard, R. N. Nandi, J. S. Muenter, and B. J. Howard, J. Chem. Phys. 89, 1245 (1988); Z. S. Huang and R. E. Miller, Chem. Phys. 132, 185 (1989)] to determine improved ground state parameters. The major perturbations affecting the upper state are accounted for through C -type Coriolis resonances involving one dark state, whose symmetry must therefore be A1. Upper state constants are obtained for the bright and dark states. The dependence upon vibrational excitation is demonstrated to arise from excitation in the acetylene unit, only, for the former, but cannot be unravelled for the latter. © 2009 American Institute of Physics.
BibTeX:
@article{Lauzin2009,
  author = {Lauzin, C. and Didriche, K. and Lívin, J. and Herman, M. and Perrin, A.},
  title = {Investigation of the C2 H2 - CO2 van der Waals complex in the overtone range using cw cavity ring-down spectroscopy},
  journal = {Journal of Chemical Physics},
  year = {2009},
  volume = {130},
  article number = {204306},
  doi = {10.1063/1.3137069}
}
Abstract: New theoretical and experimental results on the acetylene-Ar van der Waals complex are presented and the literature is reviewed. New ab initio calculations at the MP2 level were performed using large basis sets with diffuse functions and taking into account the basis set superposition error. It was found that the structure of acetylene is not significantly altered by the complexation and that its vibrational frequencies are only slightly lowered. Finally, it was observed that the calculated properties of the complex (structure, vibrational spectrum, bond dissociation energy) are not sensitive to the structure imposed on acetylene. Experimentally, acetylene-Ar was produced in a supersonic expansion under experimental conditions corresponding to 9 K rotational temperature. Thanks to the performances of CW-CRDS detection, the Ka = 0 ← 1, 1 ← 0, and 2 ← 1 sub- bands of the v1 + v3 band could be recorded and resolved and most of their lines assigned. Upper-state rotational constants were fitted, however not including the upper Ka = 2 state, which shows K-doubling the opposite of the expected. The Lorentzian width of most line profiles sets the mean lifetime to some 7.5 ns. Local perturbations affecting line positions and/or line widths are demonstrated. Additional series of lines tentatively attributed to acetylene-Ar are discussed.© 2009 American Chemical Society.
BibTeX:
@article{Lauzin2009a,
  author = {Lauzin, C. and Didriche, K. and Macko, P. and Demaison, J. and Lievin, J. and Herman, M.},
  title = {12C2H2-Ar van der Waals complex},
  journal = {Journal of Physical Chemistry A},
  year = {2009},
  volume = {113},
  pages = {2359-2365},
  doi = {10.1021/jp8077908}
}
Abstract: With the use of data assimilation, we study the quality of the Infrared Atmospheric Sounding Interferometer (IASI) total ozone column measurements. The IASI data are provided by the inversion of IASI radiances performed at the Laboratoire ATmosphères, Milieux, Observations Spatiales (LATMOS). This data set is initially compared on a five-month period to a three-dimensional time varying ozone field that we take as a reference. This reference field results from the combined assimilation of ozone profiles from the Microwave Limb Sounder (MLS) instrument and of total ozone columns from the SCanning Imaging Absorption spectrometer for Atmospheric CHartographY (SCIAMACHY) instrument. It has low systematic and random errors when compared to ozonesondes and Ozone Monitoring Instrument (OMI) data. The comparison shows that on average, the LATMOS-IASI data tends to overestimate the total ozone columns by 2% to 8%. The random observation error of the LATMOS-IASI data is estimated to about 7%, except over polar regions and deserts where it is higher. The daytime data have generally lower biases but higher random error than the nighttime data. Using this information, the LATMOS-IASI data are then assimilated, combined with the MLS data. This first LATMOS-IASI data assimilation experiment shows that the resulting analysis is quite similar to the one obtained from the combined MLS and SCIAMACHY data assimilation. The differences are mainly due to the lack of SCIAMACHY measurements during polar night, and to the higher LATMOS-IASI random errors especially over the southern polar region. © 2009 Author(s).
BibTeX:
@article{Massart2009,
  author = {Massart, S. and Clerbaux, C. and Cariolle, D. and Piacentini, A. and Turquety, S. and Hadji-Lazaro, J.},
  title = {First steps towards the assimilation of IASI ozone data into the MOCAGE-PALM system},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {5073-5091}
}
Abstract: All available transitions from microwave to visible region (0.2-12 105 cm-1) of the HD18O molecule were collected and tested using the RITZ computer code. Literature data were completed by transitions assigned to HD18O in long path Fourier transform absorption spectra of the H2O, HDO and D2O gas mixtures with natural abundance of oxygen-18. In addition about 40 unassigned lines between 4200 and 6600 cm-1 of our previous water study associated with the HD18O molecule have been found and assigned. The new long path absorption spectra of the HDO and D2O mixtures allow us to observe about 1000 transitions of HD18O in the 6125-10 720 cm-1 spectral region. These data have been critically analyzed and used to obtain the most complete and precise set of the experimental energy levels of this molecule. © 2009 Elsevier Ltd. All rights reserved.
BibTeX:
@article{Mikhailenko2009,
  author = {Mikhailenko, S.N. and Tashkun, S.A. and Putilova, T.A. and Starikova, E.N. and Daumont, L. and Jenouvrier, A. and Fally, S. and Carleer, M. and Hermans, C. and Vandaele, A.C.},
  title = {Critical evaluation of measured rotation-vibration transitions and an experimental dataset of energy levels of HD18O},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2009},
  volume = {110},
  pages = {597-608},
  doi = {10.1016/j.jqsrt.2009.01.012}
}
Abstract: The relativistic corrections to the magnetic dipole moment operator in the Pauli approximation were derived originally by Drake (1971 Phys. Rev. A 3 908). In the present paper, we derive their irreducible tensor-operator form to be used in atomic structure codes adopting the Fano-Racah-Wigner algebra for calculating its matrix elements. © 2009 IOP Publishing Ltd.
BibTeX:
@article{Nemouchi2009,
  author = {Nemouchi, M. and Godefroid, M.R.},
  title = {Irreducible tensor form of the relativistic corrections to the M1 transition operator},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2009},
  volume = {42},
  article number = {175002},
  doi = {10.1088/0953-4075/42/17/175002}
}
Abstract: Using high-resolution Fourier transform spectra of trans-HCOOH recorded at 5.6 μm, we carried out an extensive analysis of the strong ν3 fundamental band (carbonyl stretching mode) at 1776.83 cm-1, starting from results of a previous analysis [Weber WH, Maker PD, Johns JWC, Weinberger E. J Mol Spectrosc 1987; 121: 243-60]. As pointed out in the literature, the ν3 band is significantly perturbed by resonances due to numerous dark bands. We were able to assign series belonging to the ν5+ν7, ν5+ν9, ν6+ν7 and ν6+ν9 dark bands, located at 1843.48, 1792.63, 1737.96 and 1726.40 cm-1, respectively. The model used to calculate energy levels accounts partly for the observed resonances, and enabled us to reproduce most of the observed line positions, within their experimental uncertainties. We also determined absolute line intensities with an accuracy estimated to 15%. Finally, we generated, for the first time, a list of line parameters for the 5.6 μm region of trans-formic acid. © 2008 Elsevier Ltd. All rights reserved.
BibTeX:
@article{Perrin2009,
  author = {Perrin, A. and Vander Auwera, J. and Zelinger, Z.},
  title = {High-resolution Fourier transform study of the ν3 fundamental band of trans-formic acid},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2009},
  volume = {110},
  pages = {743-755},
  doi = {10.1016/j.jqsrt.2008.09.006}
}
Abstract: We present a line shape analysis of the P(2) and P(7) transitions of CO broadened by Xe in the fundamental band. The spectra were recorded at 349 K using a difference frequency laser spectrometer. To obtain information on the influence of Dicke narrowing, relaxation speed dependence, and line mixing effects, several models for implementation of Dicke narrowing and (or) speed-dependent effects are discussed. From experimental data analysis, we conclude that line shape models taking into account the Dicke effect only fail in the high pressure regime and lead to optical diffusion parameters that are much larger than the kinetic diffusion ones. On the contrary, a fair interpretation of data is obtained from speed-dependent models, so that it is possible to derive a quantitative estimate of optical diffusion effects that appear much smaller than the kinetic diffusion ones. Xe-broadening coefficients of CO lines in the fundamental band at 297 and 349 K are calculated from a semiclassical formalism involving successively two intermolecular potentials, the atom-atom Lennard-Jones model, and a three-term expansion of Legendre polynomials with four adjustable parameters.
BibTeX:
@article{Predoi-Cross2009,
  author = {Predoi-Cross, A. and Rohart, F. and Bouanich, J.-P. and Hurtmans, D.R.},
  title = {Xenon-broadened CO line shapes in the fundamental band at 349 K},
  journal = {Canadian Journal of Physics},
  year = {2009},
  volume = {87},
  pages = {485-498},
  doi = {10.1139/P08-123}
}
Abstract: Emission spectra of WO have been observed in the 4000-35 000 cm-1 region using a Fourier transform spectrometer. Molecules were produced by exciting a mixture of WCl6 vapor and He in a microwave discharge lamp. A 3Σ- state has been assigned as the ground state of WO based on a rotational analysis of the observed bands and ab initio calculations. After rotational analysis, a majority of strong bands have been classified into three groups. Most of the transitions belonging to the first group have an Ω = 0+ state as the lower state while the bands in the second group have an Ω′′ = 1 state as the lower state. These two lower states have been assigned as X0+ and X1 spin components of the X3Σ- ground state of WO. The third group consists of additional bands interconnected by common vibrational levels involving some very low-lying states. The spectroscopic properties of the low-lying electronic states have been predicted from ab initio calculations. The details of the rotational analysis are presented and an attempt has been made to explain the experimental observations in the light of the ab initio results. © 2009 Elsevier Inc. All rights reserved.
BibTeX:
@article{Ram2009,
  author = {Ram, R.S. and Liévin, J. and Bernath, P.F.},
  title = {Fourier transform emission spectroscopy and ab initio calculations on WO},
  journal = {Journal of Molecular Spectroscopy},
  year = {2009},
  volume = {256},
  pages = {216-227},
  doi = {10.1016/j.jms.2009.04.010}
}
Abstract: Although the global methane (CH4) concentration has more than doubled since pre-industrial times, local emission sources are still poorly identified and quantified. Instruments onboard satellites can improve our knowledge about the methane global distribution owing to their very good spatial coverage. The IASI (Infrared Atmospheric Sounding Interferometer) instrument launched on the European MetOp-A platform is a Fourier transform spectrometer which measures the thermal infrared radiation emitted by the Earth and its atmosphere. In this paper, we present the first global distribution of methane total columns (mostly sensitive to the middle troposphere) from the IASI spectra using the methane &amp;nu;4 absorption band. The retrieval spectral range was set in order to minimize possible spectroscopic issues. Results are discussed in terms of error budget and vertical sensitivity. In addition, we study the gain of information on surface methane concentrations provided by using the &amp;nu;3 band, which is partly covered by IASI on the short-wave end of the spectra (extending to 2760 cm&amp;minus;1), where solar reflection contributes significantly.
BibTeX:
@article{Razavi2009,
  author = {Razavi, A. and Clerbaux, C. and Wespes, C. and Clarisse, L. and Hurtmans, D. and Payan, S. and Camy-Peyret, C. and Coheur, P.F.},
  title = {Characterization of methane retrievals from the IASI space-borne sounder},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {7889-7899}
}
Abstract: Satellite-based remote sensing measurements of volcanic sulfur dioxide (SO2) provide critical information for reducing volcanic hazards. This paper describes the use of SO2 measurements from the thermal infrared sounder IASI and the UV-VIS instrument GOME-2 in services related to aviation hazard and early warning of volcanic unrest. The high sensitivity of both instruments to SO2 allows the detection and global tracking of volcanic eruption plumes and makes them a valuable tool for volcanic aviation hazard mitigation. The GOME-2 and IASI SO2 data are produced in near-real time and distributed to the Volcanic Ash Advisory Centers (VAACS) to assist them in issuing alerts to airlines and air traffic control organizations. Examples of recent eruptions affecting air traffic are presented including Jebel al Tair (Yemen, September 2007), Mount Okmok (Alaska, July 2008), and Mount Kasatochi (Alaska, August 2008). In addition, GOME-2 can detect changes in the SO2 emissions from passively degassing volcanoes and, therefore, provide critical information for hazard assessment. The monitoring of pre-emptive degassing by GOME-2 is used in early warning of volcanic activity by a mobile volcano fast response system in combination with numerous other parameters, such as seismicity, deformation, and thermal anomalies. © 2009, The Institute of Electrical and Electronics Engineers, Inc.
BibTeX:
@article{Rix2009,
  author = {Rix, M. and Valks, P. and Hao, N. and Loyola, D.G.R. and Zimmer, W. and Emmadi, S. and Rix, M. and van Geffen, J. and Clerbaux, C. and Clerbaux, C. and Clarisse, L. and Coheur, P.-F. and Erbertseder, T.},
  title = {Satellite Monitoring of Volcanic Sulfur Dioxide Emissions for Early Warning of Volcanic Hazards},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  year = {2009},
  volume = {2},
  pages = {196-206},
  doi = {10.1109/JSTARS.2009.2031120}
}
Abstract: All 18 219 vibration-rotation absorption lines of 13CH 12CH published in the literature, accessing substates up to 9400 cm-1 and including some newly assigned, were simultaneously fitted to J-dependent Hamiltonian matrices exploiting the well-known vibrational polyad or cluster block-diagonalization, in terms of the pseudo quantum numbers Ns = V1 + V2 + V3 and Nr = 5V1 + 3V2 + 5V3 + V4 + V5, also accounting for k = l4 + l5 parity and e/f symmetry properties. Some 1761 of these lines were excluded from the fit, corresponding either to blended lines, for about 30% of them, or probably to lines perturbed by Coriolis for the remaining ones. The dimensionless standard deviation of the fit is 1.10, and 317 vibration-rotation parameters are determined. These results significantly extend those of a previous report considering levels below only 6750 cm-1 [Fayt, A.; et al. J. Chem. Phys. 2007, 126, 114303]. Unexpected problems are reported when inserting in the global fit the information available on higher-energy polyads, extending from 9300 to 10 120 cm-1. They are tentatively interpreted as resulting from a combination of the relative evolution of the two effective bending frequencies and long-range interpolyad low-order anharmonic resonances. The complete database, made of 18 865 vibration-rotation lines accessing levels up to 10 120 cm-1, is made available as Supporting Information. © 2009 American Chemical Society.
BibTeX:
@article{Robert2009,
  author = {Robert, S. and Amyay, B. and Fayt, A. and Di Lonardo, G. and Fusina, L. and Tamassia, F. and Herman, M.},
  title = {Vibration-rotation energy pattern in acetylene: 13CH 12CH up to 10 120 cm-1},
  journal = {Journal of Physical Chemistry A},
  year = {2009},
  volume = {113},
  pages = {13251-13259},
  doi = {10.1021/jp904000q}
}
BibTeX:
@article{Rothman2009,
  author = {Rothman, L.S. and Brown, L.R. and Vander Auwera, J.},
  title = {Preface},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2009},
  volume = {110},
  pages = {531-532},
  doi = {10.1016/j.jqsrt.2009.02.025}
}
Abstract: This paper describes the status of the 2008 edition of the HITRAN molecular spectroscopic database. The new edition is the first official public release since the 2004 edition, although a number of crucial updates had been made available online since 2004. The HITRAN compilation consists of several components that serve as input for radiative-transfer calculation codes: individual line parameters for the microwave through visible spectra of molecules in the gas phase; absorption cross-sections for molecules having dense spectral features, i.e. spectra in which the individual lines are not resolved; individual line parameters and absorption cross-sections for bands in the ultraviolet; refractive indices of aerosols, tables and files of general properties associated with the database; and database management software. The line-by-line portion of the database contains spectroscopic parameters for 42 molecules including many of their isotopologues. © 2009 Elsevier Ltd.
BibTeX:
@article{Rothman2009a,
  author = {Rothman, L.S. and Gordon, I.E. and Barbe, A. and Benner, D.C. and Bernath, P.F. and Birk, M. and Boudon, V. and Brown, L.R. and Campargue, A. and Champion, J.-P. and Chance, K. and Coudert, L.H. and Dana, V. and Devi, V.M. and Fally, S. and Flaud, J.-M. and Gamache, R.R. and Goldman, A. and Jacquemart, D. and Kleiner, I. and Lacome, N. and Lafferty, W.J. and Mandin, J.-Y. and Massie, S.T. and Mikhailenko, S.N. and Miller, C.E. and Moazzen-Ahmadi, N. and Naumenko, O.V. and Nikitin, A.V. and Orphal, J. and Perevalov, V.I. and Perrin, A. and Predoi-Cross, A. and Rinsland, C.P. and Rotger, M. and Šimečková, M. and Smith, M.A.H. and Sung, K. and Tashkun, S.A. and Tennyson, J. and Toth, R.A. and Vandaele, A.C. and Vander Auwera, J.},
  title = {The HITRAN 2008 molecular spectroscopic database},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2009},
  volume = {110},
  pages = {533-572},
  doi = {10.1016/j.jqsrt.2009.02.013}
}
Abstract: The total and partial photodissociation cross sections of the molecular ion HeH+ are computed by time-dependent methods for fragmentation into the excited shells n=1,2,3 up to a photon energy of 40 eV. Σ1 + and Π1 states are considered for parallel and perpendicular transitions for different initial rotational or vibrational excitations. Nonadiabatic radial and rotational couplings are taken into account. The results from coupled-channel equations are compared with the Born-Oppenheimer approximation. A time-dependent calculation with a femtosecond laser pulse is carried out to simulate a recent crossed beam photodissociation imaging experiment with vacuum ultraviolet free-electron laser. The dominance of photodissociation perpendicular to the photon polarization is confirmed. © 2009 The American Physical Society.
BibTeX:
@article{Sodoga2009