基于遥感和GIS的喜马拉雅山科西河流域冰湖变化特征分析

受全球气候变暖的影响, 冰川退缩, 冰湖数量增多和面积增大被认为指示气候变化的重要依据, 冰湖面积增大导致其潜在危险性增大. 因此, 研究冰湖的变化对于气候变化和冰湖灾害研究具有重要意义. 基于Landsat TM/ETM+遥感影像采用人工解译的方法, 获取了喜马拉雅山地区科西河流域1990年前后、2000年和2010年的冰湖数据, 并对冰湖面积>0.1 km²且一直存在的199个冰湖的面积和长度变化进行对比分析. 结果表明: 科西河流域内面积>0.1 km²的冰湖的面积呈现增加趋势, 1990年冰湖面积为73.59 km², 2010年冰湖面积增加至86.12 km². 科西河流域内喜马拉雅山南北坡冰湖变化存在差异, 喜马拉雅山北坡变化较大的冰湖主要分布在海拔4 800~5 600 m之间, 而南坡变化较大的冰湖主要分布在海拔4 300~5 200 m之间; 喜马拉雅山北坡的冰湖有65%的冰湖表现扩张, 且扩张冰湖的面积主要是由冰湖在靠近终碛垅的一端基本不发生变化, 而仅在靠近冰川一端发生变化贡献的; 喜马拉雅山南坡的冰湖有32%的冰湖变化表现扩张, 且扩张的冰湖面积主要来自于冰面湖扩张. 在科西河流域内, 位于喜马拉雅山北坡的冰湖平均变化速度略高于南坡的冰湖平均变化速度.

Analysis of the characteristics of glacial lake variation in the Koshi River basin,the Himalayas based on RS and GIS

Glacier retreating and increasing number and area of glacial lakes are considered as an important evidence which indicates climate change; the increasing area of lakes makes the lake more dangerous. Therefore, study of the change of glacial lakes is of great significance for research of climate change and glacial lake disaster. Based on Landsat TM/ETM+ remote sensing images, using the method of artificial interpretation, three sets of glacial lake data of the Koshi River basin in 1990, 2000 and 2010,were obtained, the area and length change of 199 glacial lakes, which were surviving lakes with area greater than 0.1 km², were analyzed, the followings were revealed:1)The total area of glacial lakes with area larger than 0.1 km² in the basin was increasing, from 73.59 km² in 1990 to 86.12 km² in 2010; 2) In the basin, variation of glacial lakes on the southern slopes of the Himalayas was different from that on the northern slopes of the Himalayas, for example, on the northern slopes, the more changed glacial lakes were located in between the elevations of 4 800 m and 5 600 m, while on southern slopes, they were located in between the elevations of 4 300 m and 5 200 m. On the northern slopes, 65% of glacial lakes was expanding, and the main expanded area was located in the contact of lake with glacier terminal; on the southern slopes, 32% of glacial lakes was expanding, and the main expanding was supra-glacial lake expanding; 3)On the average, the change velocity of glacial lake on northern slopes is slightly greater than that on the southern slopes in the basin.