音苏盖提冰川表面流速特征分析

跃动冰川的监测相对比较困难。本文采用Sentinel-1所携带的C波段合成孔径雷达特征匹配方法(Feature-Tracking)获得了喀喇昆仑北坡克勒青河谷音苏盖提冰川物质平衡年内比较详细的冰川表面流速。分析发现:选取的音苏盖提三条分支冰川中,南斯嘎姆里冰川(Skamri Glacier)流速整体大于其余两条,三条分支均存在快速运动区,斯嘎姆里冰川和北分支积累区流速突增,可能存在雪崩现象;两条南分支冰川整体流速夏季大于其他季节,而北分支冬季流速大于其他季节。虽然三条分支均存在快速运动区域,但是即使是流速最快的南斯嘎姆里冰川在物质平衡年内的运动速度也只有119 m·a-1,说明该物质平衡年内音苏盖提冰川并不处于跃动期。

An Analysis of Surface Velocities on Yengisogat Glacier,Karakoram Mountains

There have been only limited studies on surge glaciers in the remote areas. In this study, the authors mapped surface velocities of the Yengisogat Glacier located in the Shaksgam River in Karakoram Mountains by using feature-tracking method on 12 pairs of Sentinel-1 images. These images are presently developed by the European Space Agency (ESA) for Copernicus Global Monitoring Program. The results show that the main streamline of the glacier (maximum velocity line) is close to the centerline of the glacier geometry and the main streamline slants to the outside in curved flow; the velocity decreases from the centerline to both sides. A comparative analysis of the study region was employed to discuss the flow velocity of the three tributaries of the Yengisogat Glacier. According to the results obtained, the south tributary (Skamri Glacier) mainly contributes to the main flow of the glacier; there exist fast movement blocks for three tributaries; there are areas with abrupt increasing deformation which are interpreted as avalanche probably; the velocities of two south tributaries in the summer are faster than in other seasons, but the north tributary is opposite. Even the fastest velocity of south Skamri Glacier was 119 m?a-1, indicating that the Yengisogat Glacier was not surging in this year.