Sensitivity of modelled sulfate aerosol and its radiative effect on climate to ocean DMS concentration and air–sea flux
Dimethylsulfide (DMS) is a well-known marine trace gas that is emitted from the ocean and subsequently oxidizes to sulfate in the atmosphere. Sulfate aerosols in the atmosphere have direct and indirect effects on the amount of solar radiation reaching the Earth's surface. Thus, as a potentia...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/10847/2016/acp-16-10847-2016.pdf |
| Summary: | Dimethylsulfide (DMS) is a well-known marine trace gas that is emitted from
the ocean and subsequently oxidizes to sulfate in the atmosphere. Sulfate
aerosols in the atmosphere have direct and indirect effects on the amount of
solar radiation reaching the Earth's surface. Thus, as a potential source of
sulfate, ocean efflux of DMS needs to be accounted for in climate studies.
Seawater concentration of DMS is highly variable in space and time, which in
turn leads to high spatial and temporal variability in ocean DMS emissions.
Because of sparse sampling (in both space and time), large uncertainties
remain regarding ocean DMS concentration. In this study, we use an
atmospheric general circulation model with explicit aerosol chemistry
(CanAM4.1) and several climatologies of surface ocean DMS concentration to
assess uncertainties about the climate impact of ocean DMS efflux. Despite
substantial variation in the spatial pattern and seasonal evolution of
simulated DMS fluxes, the global-mean radiative effect of sulfate is
approximately linearly proportional to the global-mean surface flux of DMS;
the spatial and temporal distribution of ocean DMS efflux has only a minor
effect on the global radiation budget. The effect of the spatial structure,
however, generates statistically significant changes in the global-mean
concentrations of some aerosol species. The effect of seasonality on the net
radiative effect is larger than that of spatial distribution and is
significant at global scale. |
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| ISSN: | 1680-7316 1680-7324 |