论文部分内容阅读
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.
Affected by global warming, retreat of glaciers, the increase in the number and area of glacial lakes are considered as an important basis for indicating climate change, and as the area of glacial lakes increases, the potential risks are increased. Therefore, Changes and glacier disaster research is of great significance.Using artificial interpretation method of Landsat TM / ETM + remote sensing images, the data of glacial lake before and after 1990, 2000 and 2010 in the Koshi River Basin in the Himalayas were obtained, The area and length of 199 glacial lakes with an area of> 0.1 km2 and persisting are comparatively analyzed.The results show that the area of glacial lakes with an area of> 0.1 km2 in the Kexi River basin shows an increasing trend, and in 1990 the glacial lakes area was 73.59 km2, The area of glacial lake increased to 86.12 km2 in 2010. There were differences in glacial lakes in the northern and southern slopes of the Himalayas in the Keshe River basin, and the glacial lakes with large changes in the northern slope of the Himalayas mainly distributed between 4 800 and 5 600 m above sea level, Most of the glacial lakes are located at altitudes of 4 300-5 200 m; 65% of the glaciers in the northern slopes of the Himalayas are expanded, and the area of the expansive glacial lakes is mainly dominated by glaciers near the final moraine垅Of the glaciers in the Himalayas; 32% of glaciers in the southern slope of the Himalayas showed an expansion, and the expansion of glacial lakes mainly came from the expansion of the ice-covered lake. Within the Xihe River Basin, the average speed of ice-lake changes on the northern slope of the Himalayas is slightly higher than that of the average on the south slope.