南极乔治王岛柯林斯冰帽小冰穹物质平衡特征的初步分析

A PRIMARY ANALYSIS OF MASS BALANCE CHARACTERISTICS ON SMALL DOME OF COLLINS ICE CAP,KING GEORGE ISLAND,ANTARCTICA

柯林斯冰帽小冰穹属于冷季补给型冰川。该冰穹高差不大，但末端比顶部的消融期长两个月；暖季消融随高度上升迅速递减。冷季积累随高度的变化显著。ＳＤＳ断面１９９１／１９９２年度物质平衡差额为１６３ｍｍ，零平衡线海拔高度为１４０ｍ，比动力平衡线低２０ｍ。其物质平衡特征表现为物质平衡梯度较大，而物质平衡水平较低，稳定性系数较小。

Some mass balance characteristics on small dome of Collins Ice Cap were analyzed according to a full year measurement data of mass balance on small dome of the ice cap in 1991/1992.The small dome belongs to the type of glacial mass supplied in cold season,periods of accumulation and ablation were distinguished clearly.Although the range of the height of small dome is not large,the melting period at terminal was two months longer than that at the top; Amount of ablation in warm season decreased rapidly with increase of the height.Affected mainly by the undulation of glacial surface, accumulation in cold season varied remarkably.Mass balance at SDS section in 1991/1992 was a weak positive balance year with a mass balance difference of 163 mm,altitude of equilibrium line was 140m,which was 20m lower than that of dynamic equilibrium line.Mass balance characteristics showed larger mass balance gradient,lower mass balance level and smaller stability coefficient,which reflected the distinctive property of glacial mass balance under the condition of subpolar maritime climate.