TY - JOUR
T1 - Global Atmospheric Budget of Acetone
T2 - Air-Sea Exchange and the Contribution to Hydroxyl Radicals
AU - Wang, Siyuan
AU - Apel, Eric C.
AU - Schwantes, Rebecca H.
AU - Bates, Kelvin H.
AU - Jacob, Daniel J.
AU - Fischer, Emily V.
AU - Hornbrook, Rebecca S.
AU - Hills, Alan J.
AU - Emmons, Louisa K.
AU - Pan, Laura L.
AU - Honomichl, Shawn
AU - Tilmes, Simone
AU - Lamarque, Jean François
AU - Yang, Mingxi
AU - Marandino, Christa A.
AU - Saltzman, Eric S.
AU - de Bruyn, Warren
AU - Kameyama, Sohiko
AU - Tanimoto, Hiroshi
AU - Omori, Yuko
AU - Hall, Samuel R.
AU - Ullmann, Kirk
AU - Ryerson, Thomas B.
AU - Thompson, Chelsea R.
AU - Peischl, Jeff
AU - Daube, Bruce C.
AU - Commane, Róisín
AU - McKain, Kathryn
AU - Sweeney, Colm
AU - Thames, Alexander B.
AU - Miller, David O.
AU - Brune, William H.
AU - Diskin, Glenn S.
AU - DiGangi, Joshua P.
AU - Wofsy, Steven C.
N1 - Funding Information:
S.-Y.?W. is partially supported by the NCAR Advanced Study Program (ASP) Postdoctoral Fellowship. K.?H.?B. acknowledges support from the National Oceanic and Atmospheric Administration (NOAA)'s Climate and Global Change Fellowship program. Support for E.?V.?F. was provided by NASA Grant NNX16AI17G. Work at Harvard (K.?H.?B. and D.?J.?J.) was supported by the Atmospheric Chemistry Program of the US National Science Foundation (NSF). We thank NASA ESPO, the NASA DC-8 crew, and the ATom Science Team for their exceptional professionalism in support of this mission. We thank Dr. Vaishali Naik and Dr. Jian He (NOAA/GFDL) for sharing the GFDM AM4.1 modeling outputs, and three reviewers for the constructive comments.
PY - 2020/8/16
Y1 - 2020/8/16
N2 - Acetone is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere. The oceans impose a strong control on atmospheric acetone, yet the oceanic fluxes of acetone remain poorly constrained. In this work, the global budget of acetone is evaluated using two global models: CAM-chem and GEOS-Chem. CAM-chem uses an online air-sea exchange framework to calculate the bidirectional oceanic acetone fluxes, which is coupled to a data-oriented machine-learning approach. The machine-learning algorithm is trained using a global suite of seawater acetone measurements. GEOS-Chem uses a fixed surface seawater concentration of acetone to calculate the oceanic fluxes. Both model simulations are compared to airborne observations from a recent global-scale, multiseasonal campaign, the NASA Atmospheric Tomography Mission (ATom). We find that both CAM-chem and GEOS-Chem capture the measured acetone vertical distributions in the remote atmosphere reasonably well. The combined observational and modeling analysis suggests that (i) the ocean strongly regulates the atmospheric budget of acetone. The tropical and subtropical oceans are mostly a net source of acetone, while the high-latitude oceans are a net sink. (ii) CMIP6 anthropogenic emission inventory may underestimate acetone and/or its precursors in the Northern Hemisphere. (iii) The MEGAN biogenic emissions model may overestimate acetone and/or its precursors, and/or the biogenic oxidation mechanisms may overestimate the acetone yields. (iv) The models consistently overestimate acetone in the upper troposphere-lower stratosphere over the Southern Ocean in austral winter. (v) Acetone contributes up to 30–40% of hydroxyl radical production in the tropical upper troposphere/lower stratosphere.
AB - Acetone is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere. The oceans impose a strong control on atmospheric acetone, yet the oceanic fluxes of acetone remain poorly constrained. In this work, the global budget of acetone is evaluated using two global models: CAM-chem and GEOS-Chem. CAM-chem uses an online air-sea exchange framework to calculate the bidirectional oceanic acetone fluxes, which is coupled to a data-oriented machine-learning approach. The machine-learning algorithm is trained using a global suite of seawater acetone measurements. GEOS-Chem uses a fixed surface seawater concentration of acetone to calculate the oceanic fluxes. Both model simulations are compared to airborne observations from a recent global-scale, multiseasonal campaign, the NASA Atmospheric Tomography Mission (ATom). We find that both CAM-chem and GEOS-Chem capture the measured acetone vertical distributions in the remote atmosphere reasonably well. The combined observational and modeling analysis suggests that (i) the ocean strongly regulates the atmospheric budget of acetone. The tropical and subtropical oceans are mostly a net source of acetone, while the high-latitude oceans are a net sink. (ii) CMIP6 anthropogenic emission inventory may underestimate acetone and/or its precursors in the Northern Hemisphere. (iii) The MEGAN biogenic emissions model may overestimate acetone and/or its precursors, and/or the biogenic oxidation mechanisms may overestimate the acetone yields. (iv) The models consistently overestimate acetone in the upper troposphere-lower stratosphere over the Southern Ocean in austral winter. (v) Acetone contributes up to 30–40% of hydroxyl radical production in the tropical upper troposphere/lower stratosphere.
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U2 - 10.1029/2020JD032553
DO - 10.1029/2020JD032553
M3 - Article
AN - SCOPUS:85089365669
VL - 125
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
SN - 2169-897X
IS - 15
M1 - e2020JD032553
ER -