The Snow Cover of Sea Ice during the Arctic Ice Dynamics Joint Experiment, 1975 to 1976

Abstract

Data were obtained on snow depth during the Arctic Ice Dynamics Joint Experiment. In May 1975, the mean snow depth on similar multiyear floes varied across a 150-km wide area from 0.20 m in the northeast to 0.28 m in the southwest. A weighted mean snowfall for the year 1974/75 (freezeup to freezeup) was calculated to be 1.5 m, of which about 40% fell during the summer. As the snow cover melted ice was progressively exposed: ≅ 5% by 21 June, ≅ 50% by 2 July, and ≅ 90% by 13 July 1975. Summer snowfall prolonged the melting of the initial snow cover and later intermittently covered the ice. The snow cover of the winter 1975/76 began on 30 August and reached at least 67% of its depth by the end of October. Snow depths measured on a 10-m grid spacing over an area 510 by 410 m, containing small floes, ridges, rubble, and first-year ice, showed a net movement of snow by the wind from the floes to the rough ice. Despite a shorter period of accumulation, the mean snow depth was about 50% greater in a band of rough ice which formed the borders of the small floes. Twenty to thirty meters into the rough ice surrounding the small floes, the mean depth decreased to that of the floes. A minimum mean depth of snow cover is hypothesized to occur on a small floe in the size range 1000 to 3000 m² where the surrounding ridges and piles of ice are similar to those reported, i.e., 1.5 to 3.5 m high. The mean snow depth would be greater both on larger floes and on smaller floes or cakes.