Variation of the Ningchan River Glacier No.3 in the Lenglongling Range,East Qilian Mountains

The Ningchan River Glacier No.3 was investigated in July,2009.During the investigation,a control network was established around the glacier and the glacierized area,glacier terminal location and surface altitude were surveyed by using GPS-RTK.In addition,glacier depth was sounded by using EKKO GPR.Then it is possible to analyze the variation of the glacier since 1972,through comparing the topographic map,which was based on aerial photo,1972,and published in 1973,two TM images in 1995,2009,and GPS-RTK data in 2009.It is found that the glacier has been shrinking seriously in the past 37 years,the glacier terminal has retreated about 6%,the glacierized area has reduced about 13.1%,and the glacier volume has reduced about 35.3%.Thinning is the main of the glacier shrinkage.The glacier average depth reduced from 36.8 m in 1972 to 27.4 m in 2009.Meteorological data around the study area shows that climate warming in different degree has taken place in recent decades,which is the main reason of rapid glacier shrinkage.