Short-term variability of atmospheric DMS and its oxidation products at Amsterdam Island during summer time

A one-month experiment was performed at Amsterdam Island in January 1998, t o investigate the factors controlling the short-term variations of atmosphe ric dimethylsulfide (DMS) and its oxidation products in the mid-latitudes r emote marine atmosphere. High mixing ratios of DMS, sulfur dioxide (SO2) an d dimethylsulfoxide (DMSO) have been observed during this experiment, with mean concentrations of 395 parts per trillion by volume (pptv) (standard de viation, sigma = 285, n = 500), 114 pptv (sigma = 125, n = 12) and 3 pptv ( sigma = 1.2, n = 167), respectively. Wind speed and direction were identifi ed as the major factors controlling atmospheric DMS levels. Changes in air temperature/air masses origin were found to strongly influence the dimethyl sulfoxide (DMSO)/DMS and SO2/DMS molar ratios, in line with recent laborato ry data. Methanesulfonic acid (MSA) and non-sea-salt sulfate (nss-SO42-) me an concentrations in aerosols during this experiment were 12.2 +/- 6.5 pptv (1 sigma, n = 47) and 59 +/- 33 pptv (1 sigma, n = 47), respectively. Evid ence of vertical entrainment was reported following frontal passages, with injection of moisture-poor, ozone-rich air. High MSA/ nss-SO42- molar ratio s (mean 0.44) were calculated during these events. Finally following fronta l passages, few spots in condensation nuclei (CN) concentration were also o bserved.