Chemical transport models often underestimate aerosol acidity in remote regions of the atmosphere

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Authors

• Benjamin A. Nault, Aerodyne Research, Inc.
• Pedro Campuzano-Jost, University of Colorado
• Douglas A. Day, University of Colorado
• Duseong S. Jo, University of Colorado
• Jason C. Schroder, University of Colorado
• Hannah M. Allen, California Institute of Technology
• Roya Bahreini, University of California
• Huisheng Bian, Joint Center for Environmental Technology
• Donald R. Blake, University of California
• Mian Chin, NASA Goddard Space Flight Center
• Simon L. Clegg, University of East Anglia
• Peter R. Colarco, NASA Goddard Space Flight Center
• John D. Crounse, California Institute of Technology
• Michael J. Cubison, TOFWERK USA
• Peter F. DeCarlo, Johns Hopkins University
• Jack E. Dibb, University of New HampshireFollow
• Glenn S. Diskin, NASA Langley Research Center
• Alma Hodzic, National Center for Atmospheric Research
• Weiwei Hu, Chinese Academy of Sciences
• Joseph M. Katich, University of Colorado
• Michelle J. Kim, California Institute of Technology
• John K. Kodros, Colorado State University
• Agnieszka Kupc, NOAA Chemical Sciences Laboratory
• Felipe D. Lopez-Hilfiker, TOFWERK AG
• Eloise A. Marais, University College London
• Ann M. Middlebrook, NOAA Chemical Sciences Laboratory
• J. Andrew Neuman, University of Colorado
• John B. Nowak, NASA Langley Research Center
• Brett B. Palm, University of Washington
• Fabien Paulot, NOAA Geophysical Fluid Dynamics Laboratory
• Jeffrey R. Pierce, Colorado State University
• Gregory P. Schill, University of Colorado
• Eric Scheuer, University of New Hampshire, Durham
• Joel A. Thornton, University of Washington
• Kostas Tsigaridis, Columbia University
• Paul O. Wennberg, California Institute of Technology
• Christina J. Williamson, University of Colorado
• Jose L. Jimenez, University of Colorado

Abstract

The inorganic fraction of fine particles affects numerous physicochemical processes in the atmosphere. However, there is large uncertainty in its burden and composition due to limited global measurements. Here, we present observations from eleven different aircraft campaigns from around the globe and investigate how aerosol pH and ammonium balance change from polluted to remote regions, such as over the oceans. Both parameters show increasing acidity with remoteness, at all altitudes, with pH decreasing from about 3 to about −1 and ammonium balance decreasing from almost 1 to nearly 0. We compare these observations against nine widely used chemical transport models and find that the simulations show more scatter (generally R2 < 0.50) and typically predict less acidic aerosol in the most remote regions. These differences in observations and predictions are likely to result in underestimating the model-predicted direct radiative cooling effect for sulfate, nitrate, and ammonium aerosol by 15–39%.

Department

Earth Systems Research Center

Publication Date

5-14-2021

Journal Title

Communications Earth & Environment

Publisher

Nature

Digital Object Identifier (DOI)

https://dx.doi.org/10.1038/s43247-021-00164-0

Document Type

Article

Recommended Citation

Nault, B. A., P. Campuzano-Jost, D. A. Day, D. S. Jo, J. C. Schroder, H. M. Allen, R. Bahreini, H. Bian, D. R. Blake, M. Chin, S. L. Clegg, P. R. Colarco, J. D. Crounse, M. J. Cubison, P. F. DeCarlo, J. E. Dibb, G. S. Diskin, A. Hodzic, W. Hu, J. M. Katich, M. J. Kim, J. K. Kodros, A. Kupc, F. D. Lopez-Hilfiker, E. A. Marais, A. M. Middlebrook, J. A. Neuman, J. B. Nowak, B. B. Palm, F. Paulot, J. R. Pierce, G. P. Schill, E. Scheuer, J. A. Thornton, K. Tsigaridis, P. O. Wennberg, C. J. Williamson, and J. L. Jimenz (2021), Chemical transport models often underestimate aerosol acidity in remote regions of the atmosphere, Communications Earth & Environment, 2, 93. https://doi.org/10.1038/s43247-021-00164-0.

Comments

This is an open access article published by Nature in 2021 in Communications Earth & Environment, available online: https://dx.doi.org/10.1038/s43247-021-00164-0