Methanesulphonate and non-sea salt sulphate in aerosol, snow, and ice on the East Antarctic plateau

Abstract

This investigation reports the first simultaneous measurement of methanesulphonate (MSA) and non-sea salt sulphate (NSSS) in aerosols, surface snow, and ice core samples for a continental site in Antarctica (78°S, 139°E, elevation 2849 m). Aerosol MSA concentrations ranged from 0.09–0.43 nmol m−3 STP (median 0.14 nmol m−3) and were generally lower than those observed at coastal Antarctic sites. NSSS concentrations varied from 0.66–1.32 nmol m−3 stp (median 0.88 nmol m−3), comparable to those reported for other continental Antarctic locations. Whereas the MSA:NSSS molar ratio in aerosol samples was in the range 12.7–32.5% (median 17.0%), the ratio down a snow pit and ice profile varied from 1.14–55.6% (median 3.50%), reflecting the variability to be expected over a period of a decade. The chemical composition and low MSA content suggests an origin of aerosols consistent with long range transport from mid-latitudes.