Long‐term trends of biogenic sulfur aerosol and its relationship with sea surface temperature in Arctic Finland

Abstract

Abstract Forty‐seven years of week‐long total suspended particle samples from Kevo Finland were analyzed for methane sulfonic acid (MSA) and sulfate. Kevo is located 350 km north of the Arctic Circle. MSA and non‐sea‐salt sulfate (NSS‐SO 4 ) showed clear seasonal trends. MSA peaks from May to July, coinciding with warmer waters and increased biogenic activity in the surrounding seas. NSS‐SO 4 peaks in March with a minimum during the summer, the typical pattern for Arctic haze. MSA concentrations were found to be positively correlated ( p < 0.001) with sea surface temperature anomalies in the surrounding seas. MSA showed a trend of 0.405 ng/m 3 /yr (0.680%/yr) for June and July. NSS‐SO 4 concentrations at Kevo declined dramatically in the early 1990s, probably as a result of the collapse of the Soviet Union. The decline has continued since the mid‐1990s.