Numerical reconstructions of LGM climate across the Eurasian Arctic

Abstract

Although limits of the Eurasian Ice Sheet at the Last Glacial Maximum (LGM) are known relatively well from geological evidence, the palaeoclimate coexistent with this ice sheet has yet to be identified confidently. A simple ice-sheet model has been used to determine LGM climate conditions by finding the ice-sheet mass-balance configuration that permits model results to match with geological data relating to the extent of LGM ice cover. These conditions are compared with Atmospheric General Circulation Model (AGCM) calculations of the climate at the LGM, which reveal the meteorological conditions associated with the ice-sheet mass-balance. The western margin of Scandinavia is characterised by a maritime climate, influenced by the nearby warm, seasonally sea-ice free, ocean conditions. However, further east, the warming effect of the North Atlantic diminishes and an extreme polar desert climate dominates across the Kara Sea similar to East Antarctica today. The LGM climate that we establish is in contrast to many previous reconstructions involving snow-laden warm westerly winds originating from the North Atlantic affecting the entire Eurasian Arctic. Severely cold conditions across the Eurasian Arctic are compatible with a stable circulation cell over the Kara Sea that isolates the region climatically, and/or cold dry westerly winds from the Fennoscandian Ice Sheet that flow across the rest of the Eurasian Arctic.