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1. An Observation-Based, Reduced-Form Model for Oxidation in the Remote Marine Troposphere

Author

Colleen B. Baublitz, Arlene M. Fiore, Sarah M. Ludwig, Julie M. Nicely, Glenn M. Wolfe, Lee T. Murray, Róisín Commane, Michael J. Prather, Daniel C. Anderson, Gustavo Correa, Bryan N. Duncan, Melanie Follette-Cook, Daniel M. Westervelt, Ilann Bourgeois, William H. Brune, T. Paul Bui, Joshua P. DiGangi, Glenn S. Diskin, Samuel R. Hall, Kathryn McKain, David O. Miller, Jeff Peischl, Alexander B. Thames, Chelsea R. Thompson, Kirk Ullmann, and Steven C. Wofsy

Subjects
Earth Resources and Remote Sensing, Meteorology and Climatology
Abstract

The hydroxyl radical (OH) fuels atmospheric chemical cycling as the main sink for methane and a driver of the formation and loss of many air pollutants, but direct OH observations are sparse. We develop and evaluate an observation-based proxy for short term, spatial variations in OH (ProxyOH) in the remote marine troposphere using unprecedented and comprehensive measurements from the NASA Atmospheric Tomography (ATom) airborne campaign. ProxyOH is a reduced form of the OH steady-state equation representing the dominant OH production and loss pathways in the remote marine troposphere, according to box model simulations of OH constrained with ATom observations. ProxyOH comprises only eight variables that are generally observed by routine ground- or satellite-based instruments. ProxyOH scales linearly with in situ [OH] spatial variations along the ATom flight tracks (median r2 = 0.90, interquartile range = 0.80 – 0.94 across 2 km altitude by 20° latitudinal regions). We deconstruct spatial variations in ProxyOH as a first-order approximation of the sensitivity of OH variations to individual terms. Two terms modulate within-region ProxyOH variations—water vapor (H2O) and, to a lesser extent, nitric oxide (NO). This implies that a limited set of observations could offer a novel avenue for observation-based mapping of OH spatial variations over much of the remote marine troposphere. Both H2O and NO are expected to change with climate, while NO also varies strongly with human activities. We also illustrate the utility of ProxyOH as a process-based approach for evaluating inter-model differences in remote marine tropospheric OH.

Published
2023
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2. Constraining remote oxidation capacity with ATom observations

Author

Katherine R. Travis, Colette L. Heald, Hannah M. Allen, Eric C. Apel, Stephen R. Arnold, Donald R. Blake, William H. Brune, Xin Chen, Róisín Commane, John D. Crounse, Bruce C. Daube, Glenn S. Diskin, James W. Elkins, Mathew J. Evans, Samuel R. Hall, Eric J. Hintsa, Rebecca S. Hornbrook, Prasad S. Kasibhatla, Michelle J. Kim, Gan Luo, Kathryn McKain, Dylan B. Millet, Fred L. Moore, Jeffrey Peischl, Thomas B. Ryerson, Tomás Sherwen, Alexander B. Thames, Kirk Ullmann, Xuan Wang, Paul O. Wennberg, Glenn M. Wolfe, and Fangqun Yu

Published
2020
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3. Global Atmospheric Budget of Acetone: Air‐Sea Exchange and the Contribution to Hydroxyl Radicals

Author

Siyuan Wang, Eric C. Apel, Rebecca H. Schwantes, Kelvin H. Bates, Daniel J. Jacob, Emily V. Fischer, Rebecca S. Hornbrook, Alan J. Hills, Louisa K. Emmons, Laura L. Pan, Shawn Honomichl, Simone Tilmes, Jean‐François Lamarque, Mingxi Yang, Christa A. Marandino, Eric S. Saltzman, Warren de Bruyn, Sohiko Kameyama, Hiroshi Tanimoto, Yuko Omori, Samuel R. Hall, Kirk Ullmann, Thomas B. Ryerson, Chelsea R. Thompson, Jeff Peischl, Bruce C. Daube, Róisín Commane, Kathryn McKain, Colm Sweeney, Alexander B. Thames, David O. Miller, William H. Brune, Glenn S. Diskin, Joshua P. DiGangi, and Steven C. Wofsy

Published
2020
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4. Missing OH Reactivity in the Global Marine Boundary Layer

Author

Alexander B. Thames, William H. Brune, David O. Miller, Hannah M. Allen, Eric C. Apel, Donald R. Blake, T. Paul Bui, Roisin Commane, John D. Crounse, Bruce C. Daube, Glenn S. Diskin, Joshua P. DiGangi, James W. Elkins, Samuel R. Hall, Thomas F. Hanisco, Reem A Hannun, Eric Hintsa, Rebecca S. Hornbrook, Michelle J. Kim, Kathryn McKain, Fred L. Moore, Julie M. Nicely, Jeffrey Peischl, Thomas B. Ryerson, Jason M. St. Clair, Colm Sweeney, Alex Teng, Chelsea R. Thompson, Kirk Ullmann, Paul O. Wennberg, and Glenn M. Wolfe

Subjects
Geosciences (General)
Abstract

The hydroxyl radical (OH) reacts with thousands of chemical species in the atmosphere, initiating their removal and the chemical reaction sequences that produce ozone, secondary aerosols, and gas-phase acids. OH reactivity, which is the inverse of OH lifetime,influences the OH abundance and the ability of OH to cleanse the atmosphere. The NASA Atmospheric Tomography (ATom) campaign used instruments on the NASA DC-8 aircraft to measure OH reactivity and more than 100 trace chemical species. ATom presented a unique opportunity to test the completeness of the OH reactivity calculated from the chemical species measurements by comparing it to the measured OH reactivity over two oceans across four seasons. Although, throughout much of the free troposphere, the calculated OH reactivity was below the limit-of-detection for the ATom instrument used to measure OH reactivity, the instrument was able to measure the OH reactivity in and just above the marine boundary layer. The mean measured value of OH reactivity in the marine boundary layer across all latitudes and all ATom deployments was 1.9 s-1, which is 0.5 s-1larger than the mean calculated OH reactivity. The missing OH reactivity, the difference between the measured and calculated OH reactivity, varied between 0 s-1to 3.5 s-1, with the highest values over the Northern Hemisphere Pacific Ocean. Correlations of missing OH reactivity with formaldehyde, dimethyl sulfide, butanal, and sea surface temperature suggest the presence of unmeasured or unknown volatile organic compounds or oxygenated volatile organic compounds associated with ocean emissions.

Published
2020
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5. Global Airborne Sampling Reveals a Previously Unobserved Dimethyl Sulfide Oxidation Mechanism in the Marine Atmosphere

Author

Patrick R. Veres, J. Andrew Neuman, Timothy H. Bertram, Emmanuel Assaf, Glenn M. Wolfe, Christina J. Williamson, Bernadett Weinzierl, Simone Tilmes, Chelsea Thompson, Alexander B. Thames, Jason C. Schroder, Alfonso Saiz-Lopez, Andrew W. Rollins, James M. Roberts, Derek Price, Jeff Peischl, Benjamin A. Nault, Kristian H. Møller, David O. Miller, Simone Meinardi, Qinyi Li, Jean-François Lamarque, Agnieszka Kupc, Henrik G. Kjaergaard, Douglas Kinnison, Jose L. Jimenez, Christopher M. Jernigan, Rebecca S. Hornbrook, Alan Hills, Maximilian Dollner, Douglas A. Day, Carlos A. Cuevas, Pedro Campuzano-Jost, James Burkholder, T. Paul Bui, William H. Brune, Steven S. Brown, Charles A. Brock, Ilann Bourgeois, Donald R. Blake, Eric C. Apel, and Thomas B. Ryerson

Subjects
Earth Resources And Remote Sensing
Abstract

Dimethyl sulfide (DMS), emitted from the oceans, is the most abundant biological source of sulfur to the marine atmosphere. Atmospheric DMS is oxidized to condensable products that form secondary aerosols that affect Earth’s radiative balance by scattering solar radiation and serving as cloud condensation nuclei. We report the atmospheric discovery of a previously unquantified DMS oxidation product, hydroperoxymethyl thioformate (HPMTF, HOOCH2SCHO), identified through global-scale airborne observations that demonstrate it to be a major reservoir of marine sulfur. Observationally constrained model results show that more than 30% of oceanic DMS emitted to the atmosphere forms HPMTF. Coincident particle measurements suggest a strong link between HPMTF concentration and new particle formation and growth. Analyses of these observations show that HPMTF chemistry must be included in atmospheric models to improve representation of key linkages between the biogeochemistry of the ocean, marine aerosol formation and growth, and their combined effects on climate.

Published
2020
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6. The NASA Atmospheric Tomography (ATom) Mission: Imaging the Chemistry of the Global Atmosphere

Author

Elizabeth Asher, Gregory P. Schill, James W. Elkins, L. Greg Huey, Michael J. Prather, Kirk Ullmann, Susan E. Strahan, J. Andrew Neuman, Bernadett Weinzierl, Thomas F. Hanisco, Nicholas L. Wagner, Michelle J. Kim, David W. Fahey, Junhua Liu, Karl D. Froyd, Benjamin A. Nault, Maximilian Dollner, Joshua P. DiGangi, Charles A. Brock, Joshua P. Schwarz, Amy H. Butler, Leslie R. Lait, Karen H. Rosenlof, Jean-Francois Lamarque, Chelsea R. Thompson, Eric A. Ray, Huisheng Bian, Donald R. Blake, Glenn M. Wolfe, Stephen D. Steenrod, Julie M. Nicely, Thomas B. Ryerson, Paul A. Newman, Forrest Lacey, Cecilia Chang, Arlene M. Fiore, Steven C. Wofsy, Joseph M. Katich, Pedro Campuzano-Jost, John D. Crounse, C. M. Flynn, Ralph F. Keeling, Linghan Zeng, M. R. Sargent, G. J. P. Correa, Eric C. Apel, Colm Sweeney, Christina Williamson, Eric J. Morgan, Britton B. Stephens, Rodney J. Weber, Alma Hodzic, Stephen A. Montzka, Jack E. Dibb, Roisin Commane, Louis Nguyen, Yenny Gonzalez, Hannah M. Allen, Fred L. Moore, Bruce C. Daube, William H. Brune, Alexander B. Thames, Daniel M. Murphy, Jose L. Jimenez, Simone Meinardi, Sarah A. Strode, T. Paul Bui, Jason M. St. Clair, Paul O. Wennberg, Kathryn McKain, Glenn S. Diskin, Reem A. Hannun, Ilann Bourgeois, Rebecca S. Hornbrook, Samuel R. Hall, Hao Guo, Mian Chin, Andrew W. Rollins, Eric J. Hintsa, Alan J. Hills, J.W. Budney, Agnieszka Kupc, David O. Miller, Lee T. Murray, Patrick R. Veres, Siyuan Wang, and Jeff Peischl

Subjects
Atmosphere, Atmospheric Science, Atom (order theory), Tomography, Atomic physics
Abstract

This article provides an overview of the NASA Atmospheric Tomography (ATom) mission and a summary of selected scientific findings to date. ATom was an airborne measurements and modeling campaign aimed at characterizing the composition and chemistry of the troposphere over the most remote regions of the Pacific, Southern, Atlantic, and Arctic Oceans, and examining the impact of anthropogenic and natural emissions on a global scale. These remote regions dominate global chemical reactivity and are exceptionally important for global air quality and climate. ATom data provide the in situ measurements needed to understand the range of chemical species and their reactions, and to test satellite remote sensing observations and global models over large regions of the remote atmosphere. Lack of data in these regions, particularly over the oceans, has limited our understanding of how atmospheric composition is changing in response to shifting anthropogenic emissions and physical climate change. ATom was designed as a global-scale tomographic sampling mission with extensive geographic and seasonal coverage, tropospheric vertical profiling, and detailed speciation of reactive compounds and pollution tracers. ATom flew the NASA DC-8 research aircraft over four seasons to collect a comprehensive suite of measurements of gases, aerosols, and radical species from the remote troposphere and lower stratosphere on four global circuits from 2016 to 2018. Flights maintained near-continuous vertical profiling of 0.15–13-km altitudes on long meridional transects of the Pacific and Atlantic Ocean basins. Analysis and modeling of ATom data have led to the significant early findings highlighted here.

Published
2022
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7. Supplementary material to 'Constraining remote oxidation capacity with ATom observations'

Author

Katherine R. Travis, Colette L. Heald, Hannah M. Allen, Eric C. Apel, Stephen R. Arnold, Donald R. Blake, William H. Brune, Xin Chen, Roisin Commane, John D. Crounse, Bruce C. Daube, Glenn S. Diskin, James W. Elkins, Mathew J. Evans, Samuel R. Hall, Eric J. Hintsa, Rebecca S. Hornbrook, Prasad S. Kasibhatla, Michelle J. Kim, Gan Luo, Kathryn McKain, Dylan B. Millet, Fred L. Moore, Jeffrey Peischl, Thomas B. Ryerson, Tomas Sherwen, Alexander B. Thames, Kirk Ullmann, Xuan Wang, Paul O. Wennberg, Glenn M. Wolfe, and Fangqun Yu

Published
2020
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8. Supplementary material to 'Comparison of OH reactivity measurements in the atmospheric simulation chamber SAPHIR'

Author

Hendrik Fuchs, Anna Novelli, Michael Rolletter, Andreas Hofzumahaus, Eva Y. Pfannerstill, Stephan Kessel, Achim Edtbauer, Jonathan Williams, Vincent Michoud, Sebastien Dusanter, Nadine Locoge, Nora Zannoni, Valerie Gros, Francois Truong, Roland Sarda-Esteve, Danny R. Cryer, Charlotte A. Brumby, Lisa K. Whalley, Daniel Stone, Paul W. Seakins, Dwayne E. Heard, Coralie Schoemaecker, Marion Blocquet, Sebastien Coudert, Sebastien Batut, Christa Fittschen, Alexander B. Thames, William H. Brune, Cheryl Ernest, Hartwig Harder, Jennifer B. A. Muller, Thomas Elste, Dagmar Kubistin, Stefanie Andres, Birger Bohn, Thorsten Hohaus, Frank Holland, Xin Li, Franz Rohrer, Astrid Kiendler-Scharr, Ralf Tillmann, Robert Wegener, Zhujun Yu, Qi Zou, and Andreas Wahner

Published
2017
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9. Comparison of OH reactivity measurements in the atmospheric simulation chamber SAPHIR

Author

Hendrik Fuchs, Anna Novelli, Michael Rolletter, Andreas Hofzumahaus, Eva Y. Pfannerstill, Stephan Kessel, Achim Edtbauer, Jonathan Williams, Vincent Michoud, Sebastien Dusanter, Nadine Locoge, Nora Zannoni, Valerie Gros, Francois Truong, Roland Sarda-Esteve, Danny R. Cryer, Charlotte A. Brumby, Lisa K. Whalley, Daniel Stone, Paul W. Seakins, Dwayne E. Heard, Coralie Schoemaecker, Marion Blocquet, Sebastien Coudert, Sebastien Batut, Christa Fittschen, Alexander B. Thames, William H. Brune, Cheryl Ernest, Hartwig Harder, Jennifer B. A. Muller, Thomas Elste, Dagmar Kubistin, Stefanie Andres, Birger Bohn, Thorsten Hohaus, Frank Holland, Xin Li, Franz Rohrer, Astrid Kiendler-Scharr, Ralf Tillmann, Robert Wegener, Zhujun Yu, Qi Zou, Andreas Wahner, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Centre for Energy and Environment (CERI EE - IMT Nord Europe), Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Nord Europe), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Chimie Atmosphérique Expérimentale (CAE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522 (PC2A), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Deutscher Wetterdienst [Offenbach] (DWD), Centre for Energy and Environment (CERI EE), Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Lille Douai), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut für Ionenphysik und Angewandte Physik, Leopold Franzens Universität, Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Département S.A.G.E (SAGE), École des Mines de Douai (Mines Douai EMD), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Mécanique de Lille - FRE 3723 (LML), Centre National de la Recherche Scientifique (CNRS)-Université de Lille, Sciences et Technologies-Ecole Centrale de Lille-Université de Lille, and Université de Lorraine (UL)

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], 010504 meteorology & atmospheric sciences, 13. Climate action, ddc:550, [CHIM]Chemical Sciences, 010501 environmental sciences, 01 natural sciences, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

International audience; Hydroxyl (OH) radical reactivity (k OH) has been measured for 18 years with different measurement techniques. In order to compare the performances of instruments deployed in the field, two campaigns were conducted performing experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich in October 2015 and April 2016. Chemical conditions were chosen either to be representative of the atmosphere or to test potential limitations of instruments. All types of instruments that are currently used for atmospheric measurements were used in one of the two campaigns. The results of these campaigns demonstrate that OH reactivity can be accurately measured for a wide range of atmospherically relevant chemical conditions (e.g. water vapour, nitrogen oxides, various organic compounds) by all instruments. The precision of the measurements (limit of detection < 1 s −1 at a time resolution of 30 s to a few minutes) is higher for instruments directly detecting hydroxyl radicals, whereas the indirect comparative reactiv-Published by Copernicus Publications on behalf of the European Geosciences Union. 4024 H. Fuchs et al.: OH reactivity comparison in SAPHIR ity method (CRM) has a higher limit of detection of 2 s −1 at a time resolution of 10 to 15 min. The performances of the instruments were systematically tested by stepwise increasing, for example, the concentrations of carbon monoxide (CO), water vapour or nitric oxide (NO). In further experiments, mixtures of organic reactants were injected into the chamber to simulate urban and forested environments. Overall, the results show that the instruments are capable of measuring OH reactivity in the presence of CO, alkanes, alkenes and aromatic compounds. The transmission efficiency in Teflon inlet lines could have introduced systematic errors in measurements for low-volatile organic compounds in some instruments. CRM instruments exhibited a larger scatter in the data compared to the other instruments. The largest differences to reference measurements or to calculated reactivity were observed by CRM instruments in the presence of ter-penes and oxygenated organic compounds (mixing ratio of OH reactants were up to 10 ppbv). In some of these experiments , only a small fraction of the reactivity is detected. The accuracy of CRM measurements is most likely limited by the corrections that need to be applied to account for known effects of, for example, deviations from pseudo first-order conditions , nitrogen oxides or water vapour on the measurement. Methods used to derive these corrections vary among the different CRM instruments. Measurements taken with a flow-tube instrument combined with the direct detection of OH by chemical ionisation mass spectrometry (CIMS) show limitations in cases of high reactivity and high NO concentrations but were accurate for low reactivity (< 15 s −1) and low NO (< 5 ppbv) conditions.

Published
2017
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