The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
J Troe - One of the best experts on this subject based on the ideXlab platform.
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Evaluated Kinetic and Photochemical Data for Atmospheric Chemistry: Supplement VIII, Halogen Species Evaluation for Atmospheric Chemistry
Journal of Physical and Chemical Reference Data, 2000Co-Authors: Roger Atkinson, D L Baulch, R F Hampson, J A Kerr, Michel J Rossi, Richard A. Cox, J TroeAbstract:This paper updates and extends part of the previous data base of critical evaluations of the kinetics and photoChemistry of gas-phase chemical reactions of neutral species involved in Atmospheric Chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992); 26, 521 (1997); 26, 1329 (1997); 28, 191 (1999)]. The present evaluation is limited to the inorganic halogen family of Atmospherically important reactions. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 102 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each thermal reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. For each photochemical reaction the data sheets list the preferred values of the photoabsorption cross sections and the quantum yields of the photochemical reactions together with comments on how they were selected. The data sheets are intended to provide the basic physical chemical data needed as input for calculations that model Atmospheric Chemistry. A table summarizing the preferred rate data is provided, together with an appendix listing the available values of enthalpies of formation of the reactant and product species.
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evaluated kinetic and photochemical data for Atmospheric Chemistry organic species supplement vii
Journal of Physical and Chemical Reference Data, 1999Co-Authors: Roger Atkinson, D L Baulch, R F Hampson, J A Kerr, Michel J Rossi, Richard A. Cox, J TroeAbstract:This paper updates and extends part of the previous data base of critical evaluations of the kinetics and photoChemistry of gas-phase chemical reactions of neutral species involved in Atmospheric Chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992); 26, 521 (1997); 26, 1329 (1997)]. The present evaluation is limited to the organic family of Atmospherically important reactions. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 171 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each thermal reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. For each photochemical reaction the data sheets list the preferred values of the photoabsorption cross sections and the quantum yields of the photochemical reactions together with comments on how they were selected. The data sheets are intended to provide the basic physical chemical data needed as input for calculations which model Atmospheric Chemistry. A table summarizing the preferred rate data is provided, together with an Appendix listing the available values of enthalpies of formation of the reactant and product species.
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evaluated kinetic photochemical and heterogeneous data for Atmospheric Chemistry supplement v iupac subcommittee on gas kinetic data evaluation for Atmospheric Chemistry
Journal of Physical and Chemical Reference Data, 1997Co-Authors: Roger Atkinson, D L Baulch, R F Hampson, J A Kerr, Michel J Rossi, J TroeAbstract:This paper updates and extends previous critical evaluations of the kinetics and photoChemistry of gas-phase chemical reactions of neutral species involved in Atmospheric Chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992)]. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 658 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. The data sheets are intended to provide the basic physical chemical data needed as input for calculations which model Atmospheric Chemistry. A table summarizing the preferred rate data is provided, together with an appendix listing the available data on enthalpies of formation of the reactant and product species. We have also included for the first time in this series of evaluations a section on heterogeneous reactions of importance in Atmospheric Chemistry. Key words: air pollution; Atmospheric Chemistry; chemical kinetics; data evaluation; gas phase; heterogeneous Atmospheric reactions; photoabsorption cross-section, photoChemistry; quantum yield; rate coefficient.
Christoph A. Keller - One of the best experts on this subject based on the ideXlab platform.
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Scalable diagnostics for global Atmospheric Chemistry using Ristretto library (version 1.0)
Geoscientific Model Development, 2019Co-Authors: Meghana Velegar, N. Benjamin Erichson, Christoph A. Keller, J. Nathan KutzAbstract:Abstract. We introduce a new set of algorithmic tools capable of producing scalable, low-rank decompositions of global spatiotemporal Atmospheric Chemistry data. By exploiting emerging randomized linear algebra algorithms, a suite of decompositions are proposed that extract the dominant features from big data sets (i.e., global Atmospheric Chemistry at longitude, latitude, and elevation) with improved interpretability. Importantly, our proposed algorithms scale with the intrinsic rank of the global Chemistry space rather than the ever increasing spatiotemporal measurement space, thus allowing for the efficient representation and compression of the data. In addition to scalability, two additional innovations are proposed for improved interpretability: (i) a nonnegative decomposition of the data for improved interpretability by constraining the chemical space to have only positive expression values (unlike PCA analysis); and (ii) sparse matrix decompositions, which threshold small weights to zero, thus highlighting the dominant, localized spatial activity (again unlike PCA analysis). Our methods are demonstrated on a full year of global Chemistry dynamics data, showing the significant improvement in computational speed and interpretability. We show that the decomposition methods presented here successfully extract known major features of Atmospheric Chemistry, such as summertime surface pollution and biomass burning activities.
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scalable diagnostics and data compression for global Atmospheric Chemistry using ristretto library version 1 0
Geoscientific Model Development Discussions, 2018Co-Authors: Meghana Velagar, Christoph A. Keller, Benjamin N Erichson, Nathan J KutzAbstract:Abstract. We introduce a new set of algorithmic tools capable of producing scalable, low-rank decompositions of global spatio-temporal Atmospheric Chemistry data. By exploiting emerging randomized linear algebra algorithms, a suite of decompositions are proposed that extract the dominant features from big data sets (i.e. global Atmospheric Chemistry at longitude, latitude and elevation) with improved interpretability. Importantly, our proposed algorithms scale with the intrinsic rank of the global Chemistry space rather than the ever increasing spatio-temporal measurement space, thus allowing for efficient representation and compression of the data. In addition to scalability, two additional innovations are proposed for improved interpretability: (i) a non-negative decomposition of the data for improved interpretability by constraining the chemical space to have only positive expression values (unlike PCA analysis), and (ii) sparse matrix decompositions, which thresholds low-correlations to zero, thus highlighting the dominant, localized spatial activity (again unlike PCA analysis). Our methods are demonstrated on a full year of global Chemistry dynamics data, showing its significant improvement in computational speed and interpretability. We show that the here presented decomposition methods successfully extract known major features of Atmospheric Chemistry, such as summertime surface pollution and biomass burning activities. Indeed, we find that the full annual model output can be reconstructed using only 50–100 principal modes, suggesting that the presented methods offer the potential to archive model data of Atmospheric Chemistry with compression factors in the range of 200–4000 or greater. In the emerging area of big data , specifically global Chemistry monitoring, such technologies are critically enabling for real-time and computationally tractable diagnostics of both large scale simulation and measurement data.
Peter F. Bernath - One of the best experts on this subject based on the ideXlab platform.
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the Atmospheric Chemistry experiment ace
Journal of Quantitative Spectroscopy & Radiative Transfer, 2017Co-Authors: Peter F. BernathAbstract:Abstract The Atmospheric Chemistry Experiment (ACE), also called SCISAT, is a Canadian-led small satellite mission for remote sensing of the Earth’s atmosphere. ACE was launched into a low Earth circular orbit by NASA on August 12, 2003 and it continues to function nominally. The ACE instruments are a high spectral resolution (0.02 cm −1 ) Fourier Transform Spectrometer (FTS) operating from 2.2 to 13.3 μm (750–4400 cm −1 ), a spectrophotometer known as Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (MAESTRO) with wavelength coverage of 285–1020 nm and two filtered detector arrays to image the Sun at 0.525 and 1.02 μm. ACE operates in solar occultation mode to provide altitude profiles of temperature, pressure, Atmospheric extinction and the volume mixing ratios (VMRs) for several dozen molecules and related isotopologues. This paper presents a mission overview and a summary of selected scientific results.
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Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) Version 3.5 Validation
Fourier Transform Spectroscopy and Hyperspectral Imaging and Sounding of the Environment, 2015Co-Authors: Kaley A. Walker, Patrick E. Sheese, Chris D. Boone, Peter F. BernathAbstract:This paper will describe current validation results for the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) focusing on version 3.5 of the data set.
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Upper Tropospheric and Stratospheric Measurements of Atmospheric Chemistry and Trends by the Atmospheric Chemistry Experiment (ACE) Fourier Transform Spectrometer
Advances in Imaging, 2009Co-Authors: Curtis P. Rinsland, Peter F. Bernath, Linda Chiou, Chris BooneAbstract:The Atmospheric Chemistry Experiment (ACE) solar occultation FTS was launched into a 74° inclined orbit on 12 August 2003 and has been recording 0.02 cm−1 resolution infrared measurements of the free troposphere and the upper atmosphere since its science operations phase began on 21 February 2004. We highlight Atmospheric composition and trend studies that have including detections of new species and the measurement of trends for the key climate change-related species CO2 and CH4.
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Validation of water vapour profiles from the Atmospheric Chemistry Experiment (ACE)
2008Co-Authors: Michel Carleer, Kaley A. Walker, Peter F. Bernath, C. D. Boone, Kim Strong, Robert J. Sica, Cora E. Randall, Holger Vömel, J. Kar, Michael HöpfnerAbstract:The Atmospheric Chemistry Experiment (ACE) mission was launched in August 2003 to sound the atmosphere by solar occultation. Water vapour (H2O), one of the most important molecules for climate and ...
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Pressure, temperature, and volume mixing ratio retrievals for the Atmospheric Chemistry experiment
Fourier Transform Spectroscopy, 2003Co-Authors: Chris D. Boone, Peter F. BernathAbstract:Procedures are described for pressure, temperature, and volume mixing ratio retrievals for the Atmospheric Chemistry Experiment, a satellite mission for remote sensing of the Earth’s atmosphere developed under the auspices of the Canadian Space Agency.
Roger Atkinson - One of the best experts on this subject based on the ideXlab platform.
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Evaluated Kinetic and Photochemical Data for Atmospheric Chemistry: Supplement VIII, Halogen Species Evaluation for Atmospheric Chemistry
Journal of Physical and Chemical Reference Data, 2000Co-Authors: Roger Atkinson, D L Baulch, R F Hampson, J A Kerr, Michel J Rossi, Richard A. Cox, J TroeAbstract:This paper updates and extends part of the previous data base of critical evaluations of the kinetics and photoChemistry of gas-phase chemical reactions of neutral species involved in Atmospheric Chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992); 26, 521 (1997); 26, 1329 (1997); 28, 191 (1999)]. The present evaluation is limited to the inorganic halogen family of Atmospherically important reactions. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 102 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each thermal reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. For each photochemical reaction the data sheets list the preferred values of the photoabsorption cross sections and the quantum yields of the photochemical reactions together with comments on how they were selected. The data sheets are intended to provide the basic physical chemical data needed as input for calculations that model Atmospheric Chemistry. A table summarizing the preferred rate data is provided, together with an appendix listing the available values of enthalpies of formation of the reactant and product species.
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evaluated kinetic and photochemical data for Atmospheric Chemistry organic species supplement vii
Journal of Physical and Chemical Reference Data, 1999Co-Authors: Roger Atkinson, D L Baulch, R F Hampson, J A Kerr, Michel J Rossi, Richard A. Cox, J TroeAbstract:This paper updates and extends part of the previous data base of critical evaluations of the kinetics and photoChemistry of gas-phase chemical reactions of neutral species involved in Atmospheric Chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992); 26, 521 (1997); 26, 1329 (1997)]. The present evaluation is limited to the organic family of Atmospherically important reactions. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 171 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each thermal reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. For each photochemical reaction the data sheets list the preferred values of the photoabsorption cross sections and the quantum yields of the photochemical reactions together with comments on how they were selected. The data sheets are intended to provide the basic physical chemical data needed as input for calculations which model Atmospheric Chemistry. A table summarizing the preferred rate data is provided, together with an Appendix listing the available values of enthalpies of formation of the reactant and product species.
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evaluated kinetic photochemical and heterogeneous data for Atmospheric Chemistry supplement v iupac subcommittee on gas kinetic data evaluation for Atmospheric Chemistry
Journal of Physical and Chemical Reference Data, 1997Co-Authors: Roger Atkinson, D L Baulch, R F Hampson, J A Kerr, Michel J Rossi, J TroeAbstract:This paper updates and extends previous critical evaluations of the kinetics and photoChemistry of gas-phase chemical reactions of neutral species involved in Atmospheric Chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992)]. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 658 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. The data sheets are intended to provide the basic physical chemical data needed as input for calculations which model Atmospheric Chemistry. A table summarizing the preferred rate data is provided, together with an appendix listing the available data on enthalpies of formation of the reactant and product species. We have also included for the first time in this series of evaluations a section on heterogeneous reactions of importance in Atmospheric Chemistry. Key words: air pollution; Atmospheric Chemistry; chemical kinetics; data evaluation; gas phase; heterogeneous Atmospheric reactions; photoabsorption cross-section, photoChemistry; quantum yield; rate coefficient.
Michael T. Roman - One of the best experts on this subject based on the ideXlab platform.
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Atmospheric Chemistry on Uranus and Neptune.
Philosophical transactions. Series A Mathematical physical and engineering sciences, 2020Co-Authors: Julianne I. Moses, Thibault Cavalié, Leigh N. Fletcher, Michael T. RomanAbstract:Comparatively little is known about Atmospheric Chemistry on Uranus and Neptune, because remote spectral observations of these cold, distant Ice Giants are challenging, and each planet has only bee...
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Atmospheric Chemistry on Uranus and Neptune
arXiv: Earth and Planetary Astrophysics, 2020Co-Authors: Julianne I. Moses, Thibault Cavalié, Leigh N. Fletcher, Michael T. RomanAbstract:Comparatively little is known about Atmospheric Chemistry on Uranus and Neptune, because remote spectral observations of these cold, distant ``Ice Giants'' are challenging, and each planet has only been visited by a single spacecraft during brief flybys in the 1980s. Thermochemical equilibrium is expected to control the composition in the deeper, hotter regions of the atmosphere on both planets, but disequilibrium chemical processes such as transport-induced quenching and photoChemistry alter the composition in the upper Atmospheric regions that can be probed remotely. Surprising disparities in the abundance of disequilibrium chemical products between the two planets point to significant differences in Atmospheric transport. The Atmospheric composition of Uranus and Neptune can provide critical clues for unravelling details of planet formation and evolution, but only if it is fully understood how and why Atmospheric constituents vary in a three-dimensional sense and how material coming in from outside the planet affects observed abundances. Future mission planning should take into account the key outstanding questions that remain unanswered about Atmospheric Chemistry on Uranus and Neptune, particularly those questions that pertain to planet formation and evolution, and those that address the complex, coupled Atmospheric processes that operate on Ice Giants within our solar system and beyond.