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.