念青唐古拉山扎当冰川冰储量估算及冰下地形特征分析

Ice volume and characteristics of sub-glacial topography of the Zhadang Glacier,Nyainqêntanglha Range

冰川体积估算对水资源以及冰川变化研究具有重要的意义.但是实测的冰川厚度数据十分稀少,限制了冰川体积的估算.2011年5月对念青唐古拉山北坡扎当冰川进行了雷达测厚工作,获取了该冰川的厚度分布状况.基于该冰川的厚度数据,测量点的GPS数据,1970年的地形图和2010年Landsat TM影像,在ArcGIS技术的支持下,采用简单Kriging插值方法对冰川非测厚区域的厚度进行了插值计算,绘制出了冰川厚度等值线图并估算了冰川的冰储量.结果表明:冰川最大厚度出现于海拔约5 748 m靠近主流线的位置,最大冰厚度为108 m,冰川平均厚度为38.1 m,2010年冰川面积为1.73 km2,扎当冰川的冰储量为0.066 km3.将扎当冰川表面DEM与冰川厚度分布图相结合,绘制出了该冰川的冰床地形图.结果显示,在冰川厚度大的区域,冰床地形呈现近V字形分布,这与其相对平缓的冰面地形形成明显对比;同时,在冰表地形较陡区域,冰川厚度不大,冰床地形呈现U形分布.

Ice volume is an important parameter for studying water resources in arid regions and glacier variation. However, there is few measured glacial ice thickness data, restricting correct estimation of glacial ice volume. In May of 2011, ice thickness of the Zhadang Glacier on the north slopes of NyainqSntanglha Range was sounded with ground penetrating radar （with a 100 MHz antenna）. Based on the sounding data, positioning data of GPS, topographic map in 1970 and Landsat TM image in 2010, an ice thickness contour map was drawn by single Kriging interpolation method and ice volume was calculated under support of ArcGIS software. The result shows that the maximum ice thickness was 108 m at 5 748 m a. s. 1. near to the main flow line. The glacierized area was 1.73 km2 in 2010. The average ice thickness was 38.1 m and total ice volume was 0. 066 km3. Based on contour map of the glacier surface and the isoline map of ice thickness, the topography of the glacier bed was obtained. It is revealed that there is a V-shape transverse bed profile in the thicker area, which is different with the surface topography. Meanwhile, when glacier surface is steeper, ice thickness is thinner and transverse bed profile is U-shape.