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Structure and life cycle of supraglacial lakes in Dronning Maud Land

Abstract Supraglacial lakes form in Antarctic blue ice regions from penetration of solar radiation into the ice in summer. Three lakes were mapped for their structure in summers 2004–05 and 2010–11 in western Dronning Maud Land, and one was also examined for the radiation budget. The lake body consisted of two layers, each ∼1 m thick: an upper layer with a thin ice layer on top and main body of liquid water, and a lower layer containing slush and hard ice sub-layers. A sediment-rich slush pocket was found at the bottom. Hydraulic conductivity of the lake body was 0.25–30 cm s-1 depending on the stage of evolution, with 6.3 cm s-1 for closely packed slush. Albedo of the lake was 0.4–0.6 and light attenuation coefficient was 0.5–0.7 m-1. The formation and the depth scale of the lakes are determined by the light attenuation distance and thermal diffusion coefficient, limiting the growth to less than about 1.5 m in one summer. The potential winter growth is more and thus the lakes freeze up in winter in the present climatic conditions.