Climatology and implications for perennial lake ice occurrence at Bunger Hills Oasis, East Antarctica

Abstract

The Bunger Hills Oasis (66°15'S; 100°45'E), a large ice-free expanse on the coast of East Antarctica, contains many lakes, only a few of which maintain an ice cover all year. To understand the environmental conditions that allow for persistent ice cover we established an automatic meteorological station on White Smoke Lake, a perennially ice-covered lake in contact with the Apfel Glacier. The data were collected from January 1992–July 1993. The mean annual solar flux during this period was 115 W m⁻², the mean wind speed 4.6 m S⁻¹, and the mean air temperature −11.2°C. Summer degree-days above freezing (71 °C-days) are similar to regions of the Antarctic (the McMurdo Dry Valleys - 78°45'S; 163°00'E) with thick perennial lake ice but the winter freezing degree days (3987 °C-Days) are much smaller and are closer to regions with seasonal ice covers (e.g. the high Arctic). The Bunger Hills Oasis seems to be in a marginal climatic region for the persistence of thick lake ice. Therefore, the extent of glacier ice contact becomes the controlling factor in maintaining an ice cover all year. We propose that this is either through the heat sink the glacier offers, and/or the positive feedback for ice growth provided by the high albedo of the adjacent glacier.