Recent variability of atmospheric circulation patterns inferred from East Antarctica glaciochemical records

Abstract

In this study, by using ion chromatography, we analyzed the chemical composition of snow deposited in 1976–2012 at three sites within the Indian Ocean sector of East Antarctica (VK-55, SW-42, and PV-10) to establish the relationships between the formation of the chemical composition of snow and varying mechanisms of atmospheric circulation. Dating of samples was carried out on the basis of sulphate peaks related to the material derived from the Pinatubo volcanic eruption (1991). Chemical compositions of snow showed spatial inhomogeneity even over relatively short distances (of about 40 km) in central East Antarctica. The reasons for the inhomogeneity may have been related to local topography and snow redistribution by wind in areas with extremely low accumulation, as well as to peculiarities of atmospheric circulation processes. According to the principal component analysis (PCA) and 5-day backward trajectories, it was determined that for site PV-10 (400 km from the Indian Ocean coast), zonal circulation in the lower troposphere associated with the cyclonic centers of the Southern Ocean was a leading process while the inland sites (VK-55 and SW-42) were influenced by a combination of processes involving meridional circulation, air mass transport, and transformation in the troposphere over the Antarctic continent.