Characteristics of sea ice thickness and snow depth distributions of the land-fast ice during summer in Lutzow-Holmbukta, Antarctica,revealed from ship-based observations

Abstract

Sea ice observations have been conducted onboard the Antarctic Research Vessel Shirase" since . The authors summarize these data to investigate spatial and inter-annual variability of sea ice thickness and snow depth of the summer land-fast ice in Lutzow-Holmbukta. Probability density functions of annual total thickness (ice thickness+snow depth) derived from video observations are categorized into two types, i.e. a thin-ice and a thick-ice type. The total thickness distributions observed by the electro-magnetic inductive method have a clear discontinuity, which reects the past break-up of the land-fast ice. Thin rst-year ice develops oshore of this location, while multi-year ice mostly develops onshore. Ice thickness and snow depth gradually decrease toward the coast within about km oshore, probably due to snow drift driven by the strong northeasterly wind. It is concluded that the past breakup of the land-fast ice as well as snow depth have dominant inuence on the spatial distribution of ice thickness in Lutzow-Holmbukta. The extent of break-up varies signicantly year by year. The smaller extent enhances the development of thick multi-year ice, while the larger extent, coupled with the inuence of snow drift, enhances reduction or extinction of thick multi-year ice.