Atmospheric Acetaldehyde: Importance of Air-Sea Exchange and a Missing Source in the Remote Troposphere
Publication information:
Siyuan Wang, Rebecca S. Hornbrook, Alan Hills, Louisa K. Emmons, Simone Tilmes, Jean-François Lamarque, Jose L. Jimenez, Pedro Campuzano-Jost, Benjamin A. Nault, John D. Crounse, Paul O. Wennberg, Michelle Kim, Hannah Allen, Thomas B. Ryerson, Chelsea R. Thompson, Jeff Peischl, Fred Moore, David Nance, Brad Hall, James Elkins, David Tanner, L. Gregory Huey, Samuel R. Hall, Kirk Ullmann, John J. Orlando, Geoff S. Tyndall, Frank M. Flocke, Eric Ray, Thomas F. Hanisco, Glenn M. Wolfe, Jason St. Clair, Róisín Commane, Bruce Daube, Barbara Barletta, Donald R. Blake, Bernadett Weinzierl, Maximilian Dollner, Andrew Conley, Francis Vitt, Steven C. Wofsy, Daniel D. Riemer, and Eric C. Apel. 2019. “Atmospheric Acetaldehyde: Importance of Air-Sea Exchange and a Missing Source in the Remote Troposphere”. Geophysical Research Letters, 46, 10, Pp. 5601-13
Abstract
We report airborne measurements of acetaldehyde (CH3CHO) during the first and second deployments of the National Aeronautics and Space Administration Atmospheric Tomography Mission (ATom). The budget of CH3CHO is examined using the Community Atmospheric Model with chemistry (CAM-chem), with a newly developed online air-sea exchange module. The upper limit of the global ocean net emission of CH3CHO is estimated to be 34 Tg/a (42 Tg/a if considering bubble-mediated transfer), and the ocean impacts on tropospheric CH3CHO are mostly confined to the marine boundary layer. Our analysis suggests that there is an unaccounted CH3CHO source in the remote troposphere and that organic aerosols can only provide a fraction of this missing source. We propose that peroxyacetic acid is an ideal indicator of the rapid CH3CHO production in the remote troposphere. The higher-than-expected CH3CHO measurements represent a missing sink of hydroxyl radicals (and halogen radical) in current chemistry-climate models.