分析冰湖扩张特征和扩张方式及其气候意义,有利于认识冰川—冰湖—气候三者的变化关系和冰湖溃决灾害危险性程度。基于大比例尺地形图、DEM、ASTER影像等数据,分析近30年来我国喜马拉雅山区不同海拔高度冰湖变化的特征及冰湖—母冰川的相对位置的变化关系,探讨其气候效应。结果显示:(1)存在冰湖的面积增大是冰湖面积扩张的主要贡献者,占总面积净增量的67%,新增湖的面积占总面积净增量的33%;(2)不同高度带冰湖面积多呈扩张态势,净增面积在5000~5300m出现峰值,指示气候变化的垂直差异性;(3)在2000s母冰川—冰湖距离为0的冰湖,数量占扩张冰湖总数的19%,而其冰湖面积增量却占了总面积增量的60%,为冰湖扩张的主体,反映出冰湖与母冰川关系越紧密,气候效应越强烈,冰湖面积增加越显著。
The Himalayas has drawn a wide attention in the context of the changing climate.The expansion of glacial lakes shows the variation of climate changes and is of importance to understand the risks of glacial lake outburst flood.On the basis of large scale topographical maps,DEMs,ASTER,images,glacial lake area variation against elevation and the changes of distance between glacial lake and its parent glacier were analyzed and the climatic implications were discussed in the Chinese Himalaya.The results show that,in the past 30 years,(1) the survived glacial lake expansion was a dominant contributor to the increase of glacial lake area,accounting for about 67%,and new formed lakes contributed to the rest 33% of area increment;(2) glacial lake area was averagely increasing in all 100-m-elevation bands where the largest growth occurred at elevations of 5000-5300 m,indicating a vertical variety of climate changes;(3) the more closer the glacial lake is to its parent glacier,the greater the area increasing rate of the glacial lakes,and among 15 types of glacial lake-glacier distance variation,60% of net lake area increment was due to the lakes directly connected with parent glaciers in the 2000s in Chinese Himalaya.