珠穆朗玛峰东绒布冰川厚度测量与地形特征分析

Ice Thickness Observation and Landform Study of East Rongbuk Glacier,Mt. Qomolangma

冰川地形特征的研究是构建冰川流动模型的基础.根据探地雷达获取的冰川厚度数据(2009年)和1∶5万地形图(1974年),得到沿珠穆朗玛峰东绒布冰川主流线的冰厚度分布以及5条冰川槽谷的形态特征.结果表明:沿东绒布冰川主流线的平均表面坡度约为0.08,平均厚度约为190m,最大厚度约为320m(海拔6 300m);在1974—2009年间沿冰川主流线冰厚度平均减薄约30m;东绒布冰川表碛覆盖区与白冰区尚未分离,目前很可能是一条停滞冰川,冰川末端位于海拔5 540m附近(下游方向);东绒布冰川槽谷形态接近于V型,而不是U型(b指数变化范围约为0.7～1.3).

Study of the glacial landform features is the basis for developing ice flow models.The ice thickness distribution along the main flow-line together with the glacial valley shape of the East Rongbuk Glacier is revealed by using the ice thickness data obtained by ground penetrating radar sounding in 2009 and a 1∶50 000 landform map（1974）.We found that the average ice surface slope and ice thickness along the main flowline are around 0.08 and 190 m,respectively,and the maximum ice thickness is around 320 m（at 6 300 m a.s.l.）.During the period of 1974-2009,average decrease of the ice thickness along the main flow-line was around 30 m.The debris-covered and clean ice areas are now still connected,indicating that the glacier is probably stagnant at present.The terminus is at 5 540 m a.s.l.or so.The glacial troughs of the East Rongbuk Glacier are closer to ＂V＂-type rather than ＂U＂-type,with an index b ranging from 0.7 to 1.3.