Glacier Temporal-Spatial Change Characteristics in Western Nyainqentanglha Range,Tibetan Plateau 1977-2010
WANG Xu1,2,ZHOU Ai-guo1,3*,SIEGERT Florian2,4,ZHANG Zhi5,CHEN Kun-lun6 1.School of Environmental Studies,China University of Geosciences,Wuhan 430074,China 2.GeoBio Center,Ludwig-Maximilians-University,Munich 82152,Germany 3.State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences,Wuhan 430074,China 4.Remote Sensing Solutions GmbH,Isarstr.3,Munich 82065,Germany 5.Faculty of Earth Sciences,China University of Geosciences,Wuhan 430074,China 6.School of Resource and Environment,Hubei University,Wuhan 430062,China
Three atmospheric/topographic corrected Landsat images(acquired form 17/03/1977,05/02/2001,06/02/2010) have been used to map the glacier extents using threshold ratio images(BAND4/BAND5) and ISODATA unsupervised classification,respectively.A few of manual editing was made to correct the outline at ice-lake contacts and at debris covered glaciers.Spatial-temporal distribution and changes of glaciers are analyzed based on GIS and RS.Results show that(1) The glacier in WNR covered 571.81±16.01 km2 in 2010,located mainly at the elevation zone of 5 500-6 200 m;(2) The glacier retreat is obvious in recent three decades,especially in the last decade.The glacier area had decreased by 22.42%±2.90% between 1977 and 2010.(3) Compared to the period 1977-2001,the glacier retreat rate in the last decade is higher.(4) The annual mean reduction of glacier area slows down in the elevation zone of lower 5 700 m,while it speeds up between 5 800-7 000 m.(5) In Lhasa River basin the elevation zone that the glacier reduction fastest is 100 m higher than that in the Namco basin.The Lhasa river basin glacier reduction was affected by the climate change and anthropogenic activities,while the glacier retreat in Namco basin was mainly caused by climate change.(6) The rate of glacier retreat is higher in Namco basin on the northern slope(23.6%±2.88%) of research area than those on the southern slope(21.97%±2.90%).And the elevation zone where the highest rate of glacier retreat during 2001-2010 is 200 m higher than those between 1977 and 2001.It indicates that the glaciers tend to shrink in higher elevation.