1990-2011年西昆仑峰区冰川变化的遥感监测

本文应用Landsat 5、7 TM、ETM+影像分析1990-2011年昆仑山西段昆仑峰区冰川变化特征,结果表明:1990-2011年冰川面积减少16.83 km²,退缩率仅为0.65%,冰川退缩趋势不明显。单条冰川变化有进有退,中峰冰川末端在2002-2004年以661 m/a的速率前进,初步判定为跃动冰川。1991-1998年,崇测冰川面积增加9.47 km²,冰川末端以200 m/a的速率前进,不排除有跃动冰川的可能性。尽管近年来全球气温普遍上升,大量冰川处于退缩状态,但统计已有研究结果发现近50年来青藏高原存在冰川长度、面积增加,冰川物质平衡为正的现象,表现出冰川对气候变化复杂的反馈机制。通过分析气象站点和冰芯资料,研究区周边地区气温上升、降水量缓慢增加可能是冰川微弱退缩的原因之一;增强的西风环流带来更多的降水、研究区以极大陆型大规模冰川为主,也可能是冰川退缩幅度较小的原因。

Variation of West Kunlun Mountains glacier during 1990-2011

Mountain glaciers are a potential climate indicator because they are sensitive to climate changes. The water released from Kunlun Mountains glaciers is the major source of stream flow to the Tarim Basin and nearly 6.3milion people who live in the oasis of Tarim Basin rely on the glacier runoff. Remote sensing has proved to be the best method of investigating the extent of glacial variations in remote mountainous areas. Using remote sensing (RS) and geographical information system (GIS) technologies, we analyzed glacier changes in the Western Kunlun Mountains on the Northwestern Tibetan Plateau. The satellite images (Landsat TM, ETM+) from 1990 to 2011 were used to extract the extent of the glaciers. The results indicated that there was no significant change in glacier area in the study area as a whole, and the glacier area decreased about 16.83 km² (0.65%) over the 22 years. But the glacier changes were not homogeneous. The changes in single glacier area have differed among the study regions, and some glaciers advanced while other glaciers retreated. ZhongFeng glacier advanced at 661 m/a from 2002 to 2004 and we infer that the ZhongFeng glacier is a surge glacier. Chongce glacier advanced at 200 m/a from 1991 to 1998 and the glacier area increased 9.47 km². This glacier is characteristic of surge glacier. The temperature showed an increasing trend from 1960 to 2010, while precipitation increased slightly. The Guliya ice core indicates that the temperature and precipitation increased after twenty century. The increase in air temperature resulted in the slight glacier recession. The low retreat rate of the glaciers may be due to two factors: the large scale of the glaciers and the increasing precipitation accompanied by strengthening westerlies.