Snowfall phases in analysis of a snow cover in Hornsund, Spitsbergen

Abstract

Conditions influencing formation of a snow cover in southern Spitsbergen in Homsund during the winters 1988/1989 and 1989/1990 are presented. Winter snow cover consists of several overlaid layers which correspond to particular snowfall phases, distinguished on the basis of analysis of occurrence of winter precipitation and development of a snow cover in numerous snow pits. Five snowfall phases during the winter 1988/1989 and three during the winter 1989/1990 were determined. A genetic classification, including specific features of a snow cover in Spitsbergen, was applied to describe snow layers in pits. The classification covers metamorphic changes of snow: dry metamorphosis, wet metamorphosis without freezing, wet metamorphosis with freezing, and aeolian metamorphosis. Precipitation, strong winds, and winter thaws are the factors which mostly influence formation of a snow cover in the Hornsund region. Most winter precipitation is connected with inflow of relatively warm air masses from the Norwegian Sea. Short term winter thaws which occur afterwards, result in formation of a characteristic ice-crust on a snow cover. The ice-crust layer protects a snow cover against deflation. It is also a marker band which enables dating of snow. Ice crust layers are almost always the borders between particular snowfall phases. Strong winds (V > 8 m/s) significantly transform a surface layer of snow. Snow deflation, which is locally quite intensive, occurs mainly at seashore plains, mountain ridges and convex slopes.