The role of the ocean in the global atmospheric budget of acetone

• Published in: Geophysical research letters Vol. 39; no. 1
• Main Authors: Fischer, E. V., Jacob, D. J., Millet, D. B., Yantosca, R. M., Mao, J.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 01.01.2012; American Geophysical Union; John Wiley & Sons, Inc
• Subjects: Acetone; air-sea exchange; Atmosphere; Atmospheric chemistry; Atmospheric sciences; Biosphere; Boundary conditions; Carbonyl compounds; Chemical transport; chemical transport model; Earth sciences; Earth, ocean, space; Exact sciences and technology; Oceans; Photolysis; Seawater; Troposphere; atmosphere; sea water; Carbonyl compounds; models; air-sea interface; simulation; tropical zone; concentration; global; air; transport; Atmospheric chemistry; Flux density; Northern Hemisphere; Photolysis; Planetary scale; equilibrium; boundary conditions; inclusions; Acetone
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2011GL050086

Acetone is one of the most abundant carbonyl compounds in the atmosphere and it plays an important role in atmospheric chemistry. The role of the ocean in the global atmospheric acetone budget is highly uncertain, with past studies reaching opposite conclusions as to whether the ocean is a source or sink. Here we use a global 3‐D chemical transport model (GEOS‐Chem) simulation of atmospheric acetone to evaluate the role of air‐sea exchange in the global budget. Inclusion of updated (slower) photolysis loss in the model means that a large net ocean source is not needed to explain observed acetone in marine air. We find that a simulation with a fixed seawater acetone concentration of 15 nM based on observations can reproduce the observed global patterns of atmospheric concentrations and air‐sea fluxes. The Northern Hemisphere oceans are a net sink for acetone while the tropical oceans are a net source. On a global scale the ocean is in near‐equilibrium with the atmosphere. Prescribing an ocean concentration of acetone as a boundary condition in the model assumes that ocean concentrations are controlled by internal production and loss, rather than by air‐sea exchange. An implication is that the ocean plays a major role in controlling atmospheric acetone. This hypothesis needs to be tested by better quantification of oceanic acetone sources and sinks. Key Points We updated the global atmospheric acetone budget using a global model We can reproduce observed marine atmospheric concentrations and air‐sea fluxes The ocean plays a major role in controlling atmospheric acetone