@article{3978992d7a0444cf850f8554e64f0255,
title = "Mapping hydroxyl variability throughout the global remote troposphere via synthesis of airborne and satellite formaldehyde observations",
abstract = "The hydroxyl radical (OH) fuels tropospheric ozone production and governs the lifetime of methane and many other gases. Existing methods to quantify global OH are limited to annual and global-to-hemispheric averages. Finer resolution is essential for isolating model deficiencies and building process-level understanding. In situ observations from the Atmospheric Tomography (ATom) mission demonstrate that remote tropospheric OH is tightly coupled to the production and loss of formaldehyde (HCHO), a major hydrocarbon oxidation product. Synthesis of this relationship with satellite-based HCHO retrievals and model-derived HCHO loss frequencies yields a map of total-column OH abundance throughout the remote troposphere (up to 70% of tropospheric mass) over the first two ATom missions (August 2016 and February 2017). This dataset offers unique insights on near-global oxidizing capacity. OH exhibits significant seasonality within individual hemispheres, but the domain mean concentration is nearly identical for both seasons (1.03 ± 0.25 × 106 cm−3), and the biseasonal average North/South Hemisphere ratio is 0.89 ± 0.06, consistent with a balance of OH sources and sinks across the remote troposphere. Regional phenomena are also highlighted, such as a 10-fold OH depression in the Tropical West Pacific and enhancements in the East Pacific and South Atlantic. This method is complementary to budget-based global OH constraints and can help elucidate the spatial and temporal variability of OH production and methane loss.",
author = "Wolfe, {Glenn M.} and Nicely, {Julie M.} and Clair, {Jason M.St} and Hanisco, {Thomas F.} and Jin Liao and Oman, {Luke D.} and Brune, {William B.} and David Miller and Alexander Thames and Abad, {Gonzalo Gonz{\'a}lez} and Ryerson, {Thomas B.} and Thompson, {Chelsea R.} and Jeff Peischl and Kathryn McCain and Colm Sweeney and Wennberg, {Paul O.} and Michelle Kim and Crounse, {John D.} and Hall, {Samuel R.} and Kirk Ullmann and Glenn Diskin and Paul Bui and Cecilia Chang and Jonathan Dean-Day",
note = "Funding Information: ACKNOWLEDGMENTS. We thank all of the NASA pilots, crew, logistical personnel, and science leadership who facilitated the ATom mission. We thank Clare Flynn for assembling the merged dataset used to constrain 0-D box model simulations, and we also thank the many scientists contributing observations to this dataset. We thank Can Li, Joanna Joiner, Arlene Fiore, and Colleen Baublitz for helpful discussions and feedback. This work was supported by the NASA ATom Earth Venture Suborbital-2 Program. The NASA Goddard Space Flight Center (GSFC) team acknowledges support from Atmospheric Composition Campaign Data Analysis and Modeling Grant NNX14AP48G, the NASA Upper Atmospheric Research Program, and the NASA Tropospheric Composition Program. J.M.N. was also supported by an appointment to the NASA Postdoctoral Program at the NASA GSFC, administered by the Universities Space Research Association under contract. OMI HCHO columns were developed with NASA support from Atmospheric Composition Modeling and Analysis Grant NNX17AH47G and the Aura Science Team. The Modern-Era Retrospective Analysis for Research and Applications 2 GMI simulation was supported by the NASA Modeling, Analysis, and Prediction Program and computational resources from the NASA Center for Climate Simulation. M.K. was funded by NSF Atmospheric and Geospace Sciences Postdoctoral Research Fellowship 1524860. Finally, we thank three anonymous reviewers for their expert critique of the manuscript. Funding Information: We thank all of the NASA pilots, crew, logistical personnel, and science leadership who facilitated the ATom mission. We thank Clare Flynn for assembling the merged dataset used to constrain 0-D box model simulations, and we also thank the many scientists contributing observations to this dataset. We thank Can Li, Joanna Joiner, Arlene Fiore, and Colleen Baublitz for helpful discussions and feedback. This work was supported by the NASA ATom Earth Venture Suborbital-2 Program. The NASA Goddard Space Flight Center (GSFC) team acknowledges support from Atmospheric Composition Campaign Data Analysis and Modeling Grant NNX14AP48G, the NASA Upper Atmospheric Research Program, and the NASA Tropospheric Composition Program. J.M.N. was also supported by an appointment to the NASA Postdoctoral Program at the NASA GSFC, administered by the Universities Space Research Association under contract. OMI HCHO columns were developed with NASA support from Atmospheric Composition Modeling and Analysis Grant NNX17AH47G and the Aura Science Team. The Modern-Era Retrospective Analysis for Research and Applications 2 GMI simulation was supported by the NASA Modeling, Analysis, and Prediction Program and computational resources from the NASA Center for Climate Simulation. M.K. was funded by NSF Atmospheric and Geospace Sciences Postdoctoral Research Fellowship 1524860. Finally, we thank three anonymous reviewers for their expert critique of the manuscript. Publisher Copyright: {\textcopyright} 2019 National Academy of Sciences. All rights reserved.",
year = "2019",
month = jun,
day = "4",
doi = "10.1073/pnas.1821661116",
language = "English (US)",
volume = "166",
pages = "11171--11180",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
publisher = "National Academy of Sciences",
number = "23",
}