1971 - 2015年羌塘高原藏色岗日冰川变化

通过对地形图和Landsat系列影像的目视解译获取冰川边界， 分析得到1971 - 2015年羌塘高原藏色岗日冰川变化。结果表明： 2015年研究区有冰川84条， 总面积（297.65±4.29） km2； 1971 - 2015年冰川持续退缩， 面积减少（19.32±24.31） km2， 年均退缩率为（0.14±0.17）%， 退缩较慢； 五个时段年均退缩速率分别为（0.12±1.46）%、 （0.20±0.32）%、 （0.12±0.50）%、 （0.01±0.57）%和（0.16±0.31）%。消融期（5 - 9月）温度的上升是研究区冰川退缩的主要驱动力。小规模冰川（<0.5 km2）的退缩率14.00%大于大规模冰川（>2 km2）的5.58%； 北朝向冰川的退缩率8.06%大于南朝向冰川的4.16%； 冰川数量由78条增加到84条反映出大冰川在退缩的过程中分裂成小冰川； 2条冰川末端发生前进。

Variation of glaciers at Zangser Kangri on the Qiangtang Plateau during 1971 - 2015

The inaccessibility of many glaciers makes remote sensing data crucial at glacier change monitoring. Glacier outlines were digitized on-screen manually from topographic maps and Landsat images. Glacier change characteristics were analyzed at Zangser Kangri on the Qiangtang Plateau from 1971 to 2015. The results reveal there are 84 glaciers in 2015， covering an area of （297.65±4.29） km2， while 56 of them are smaller than 1 km2 and there are 44 and 16 glaciers facing north and south respectively. Glacier area decreased by （19.32±24.31） km2 from 1971 to 2015， at the annual shrinkage rate of （0.14±0.17）%， which is relatively slow. The annual shrinkage rates are （0.12±1.46）% for 1971 - 1977， （0.20±0.32）% for 1977 - 1993， （0.12±0.50）% for 1993 - 2000， （0.01±0.57）% for 2000 - 2006 and （0.16±0.31）% for 2006 - 2015， respectively. Based on the meteorological data， ERA-Interim reanalysis and ice cores records， the increased ablation season （May to September） temperature is the main driving force accounting for the shrinkage. Small glaciers （<0.5 km2） retreated faster at the rate of 14.00% than big glaciers （>2 km2） at the rate of 5.58%. Northward glaciers shrank faster at the rate of 8.06% than southward glaciers at the rate of 4.16%. The increased number （from 78 to 84） of glaciers indicates big glaciers subdivided to small glaciers while retreating quickly. Two glaciers advanced during our study period.