DISTRIBUTION OF METHANESULFONATE, NSS SULFATE AND DIMETHYLSULFIDE OVER THE ATLANTIC AND THE NORTH-SEA

The concentrations of aerosol methanesulfonate (MSA) and non-sea-salt (nss) sulfate and of gaseous dimethylsulfide (DMS) were measured simultaneously in the marine atmosphere. Over the Atlantic measurements were performed during two cruises with the research vessel Polarstern between Germany (54-degrees-N) and South America (32-degrees-S, 42-degrees-S). Further sampling sites were located on a research platform and on the island Sylt in the North Sea. MSA concentrations of 1-20 ng S (MSA) m-3 and 5-100 ng S (MSA) m-3 were determined over the Atlantic and North Sea, respectively. On average, the concentration of MSA and its precursor DMS showed a good correlation, with high values being observed especially in spring. Seasonal and diurnal variations of the MSA concentration are discussed. The nss sulfate concentration was quite often influenced by advection of sulfate from continental sources. Under remote marine conditions the concentration ratio of nss sulfate and MSA ranged from 3 to 22.