Glacier Variation in the Lenglongling Range of Eastern Qilian Mountains from 1972 to 2007
CAO Bo1,PAN Bao-tian1,GAO Hong-shan1,JIANG Shao-fei1,WEN Yu-hua1 SHANGGUAN Dong-hui2(1. Key Laboratory of Western China's Environmental Systems (MOE),Lanzhou Gansu 730000,China; 2. Cold and Arid RegionsEnvironmental and Engineering Research Institute,Chinese Academy of sciences,Lanzhou Gansu 730000,China)
The Lenglongling Range of Eastern Qilian Mountains was selected as a sample region to search a method for delineating glacier extent by using Topographic maps of 1972,Landsat TM image of 1994,CBERS-2 image of 2000 and ASTER image of 2007. Only the remote sensing images of warm season and free of clouds were selected. The glacier variation of Lenglong Range was investigated by comparing digitized glacier outlines from the Chinese Glacier Inventory (CGI) surveyed in 1972 and the remote sensing images. For delineating the extent of exposed glacier ice conveniently and efficiently from images,the Interactive Data Language (IDL) program by ITT Visual Information Solutions (ITT VIS) was used. The results show that the area of 244 glaciers in the Lenglong Range decreased by 12.796 km2 or 0. 65%·a-1 from CGI to 1994,by 5.693 km2 or 1.05%·a-1 from 1994 to 2000,and by 5.797 km2 or 0.98%·a-1 from 2000 to 2007. From CGI to 2007,the total area lost was about 24.286·km2,accounting for 23.57% (0.67%·a-1) of the glacierized area. Consequently,all of the 244 glaciers in the Lenglong Range were shrinking,and 27 glaciers disappeared by 2007. The rate of glacier retreat on south slopes was faster then that on the north slopes.