Abstract:

Based on the revised First and Second Chinese Glacier Inventory and Landsat OLI remote sensing images during 2015-2016, we analyzed the spatial-temporal variation characteristics of glaciers in the Gangdisê Mountains during 1970-2016. The results of this study provide a scientific basis for the rational use of water resources in this region. The results showed that there were 3953 glaciers with a total area of 1306.45 km ² and ice volume of ~58.16 km ³ in the Gangdisê Mountains during 2015-2016. The glaciers in sizes of 0.1-5 km ² and < 0.5 km ² had the largest area and the greatest number of glaciers in the Gangdisê Mountains, respectively. In the past five decades, the area of glaciers decreased by 854.05 km ² (-1.09%/a), accounting for 39.53% of the total area of glaciers in the region in 1970. The increase of temperature in the ablation period was the most important cause of glacier retreat. Compared to other mountains in western China, the Gangdisê Mountains was the region with the strongest glacier retreat and had an accelerating tendency in recent years. The decrease of glacier area was mainly concentrated at elevations of 5600-6100 m a.s.l. and there was no change in elevation above 6500 m a.s.l. in the Gangdisê Mountains. Except for the south and southeast orientations, the number and area of glaciers were decreasing in all the orientations. Specifically, the north orientation suffered the largest area loss of glaciers and the northwest orientation witnessed the fastest retreat of glacier area. A significant feature of spatial variation showed that the rate of glacier retreat was faster from west to east in the Gangdisê Mountains. The relative change of glacier rate in the eastern section was high at -1.72%/a, followed by the middle section (-1.67%/a), and that in the western section was only -0.83%/a.

Key words: glacier change, glacier inventory, climate change, Gangdisê Mountains;