Time series of monthly mean atmospheric methane sulfonic acid (MSA, red line) and non-sea salt sulfate (nss-SO42-, blue line) concentrations. Aerosol formation from biogenic precursor gases such as algae-derived dimethyl sulfide (DMS) plays an important and crucial role in determining the Earths albedo by direct and indirect effects. This is especially true for the Southern Hemisphere, where the emission of man-made aerosol is still much less dominant than in the Northern Hemisphere. Considering the naturally derived aerosol load of the Southern Hemisphere, the atmospheric photooxidation of DMS leading to the final reaction products methane sulfonic acid (MSA) and sulfuric acid is believed to be the most important process. In contrast to sulfate, which comprises a composite signal of marine biogenic, sea salt, terrestrial, and volcanic sources, MSA is known to be virtually exclusively formed by photooxidation of DMS. The non-sea salt sulfate and MSA records from Neumayer reveal the strong seasonality of the signal with maximum concentrations in January. In addition the close correlation of nss-sulfate and MSA indicate that most of the sulfate amount in Neumayer aerosol is of marine biogenic origin and thus DMS dominates the overall sulfur budget at this site. The extraordinarily pronounced seasonality of atmospheric MSA and nss-sulfate concentrations is characteristic for coastal Antarctica and is linked with the seasonality of the sea ice coverage and insolation. Details regarding the sampling method can be found here...
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