Abstract
Results are presented on seasonal values of atmospheric dimethylsulfide (DMS), SO2, aerosol methanesulfonate (MSA), non-sea-salt sulfate (nss-SO4/2-/), NH4(+), NO3(-), and other major ions, measured between September 1985 and September 1986 in the western North Atlantic Ocean (WNAO). The results also include measurements of rainwater samples for various trace compounds. It is shown that the boundary layer atmosphere over the WNAO is impacted by continental air during all seasons. It was estimated that the biogenic DMS/sulfur flux to the WNAO atmosphere is from 0.1 to 0.3 Tg S/yr. The SO2 and nss-SO4(2-) concentrations varied strongly with wind direction, from 10 pptv in marine air to several ppbv in continentally derived air. The NH4(+) concentrations and NH4(+)/nss-SO4(-2) ratios showed a clear seasonal variation with a maximum in late summer/early fall and a minimum in late winter. (I.S.)