1972-2009年念青唐古拉山西段冰湖分布及其变化特征

冰湖是研究气候变化的重要指标之一,了解冰湖分布和变化的特征,对认识冰川与气候之间关系和冰湖溃决灾害评估有着重要意义。运用遥感资料监测念青唐古拉山西段近40a来的冰湖分布及其变化,并结合DEM研究冰湖垂直分布的变化,探讨影响冰湖分布和变化的可能因素。研究结果表明:(1)研究区冰湖数量和面积近年来都呈迅速增加趋势,冰湖增加150个,冰湖面积增加4.384km2。气温升高、冰川融水增加是冰湖增多和面积增大的主要原因;(2)冰湖垂直分布变化明显,新增冰湖个数峰值位于海拔5 500～5 700m,占新增冰湖总数的61%;新增冰湖面积峰值在海拔5 400～5 700m,占新增湖总面积的44%;冰湖面积在大部分海拔高度上均呈扩张态势;(3)海拔高于5 400m的区域,1991-2009年新增的冰湖数量远多于1972-1991年。冰湖在高海拔区分布的变化对念青唐古拉山区冰川消融以及气候垂直变化具有一定的指示作用。

Distribution and Changes Characteristics of Glacial Lakes in Western Nyainqentanglha Range During 1972-2009

Glacial lake is one of the indictors to show the variation of climatic change.It is significant to understand the distribution and change characteristics and the relationship of glaciers-glacial lakes-climate.Three atmospheric/topographic corrected Landsat images(acquired in 1972,1991,2009) have been used to Abstract the glacial lake boundaries respectively.Spatial-temporal distribution and changes of glacial lakes are analyzed based on GIS and RS.Results show that,(1) The number of glacial lakes is 312 and the surface area of glacial lakes is 7.177 km2 in 2009.The number of glacial lakes increased 150 and the area of lakes increased 4.384 km2 during 1972-2009;(2) The glacial changes exhibit a vertical variety that the largest new-formed glacial lakes located at 5 500-5 700 m zone,while most of glacial lake surface area expanded in all 100 m elevation zone where the largest increase occurred at elevation zone of 5 400-5 700 m;(3) Compared to the period 1972-1991,the number of new-formed glacial lakes is much more than the period 1991-2001 at the elevation above 5 400 m.The number of glacial lakes and the area of glacial lakes increased in recent four decades due to the climatic warming and glacier retreat.