近20年中国阿尔泰山区冰川湖泊对区域气候变化响应的时空特征

The response of glacial lakes in the Altay Mountains of China to climate change during 1992-2013

以1992年、2002年、2013年的Landsat TM/ETM+/OLI遥感影像为基础,人工解译阿尔泰山区三期冰湖边界与类型,叠置获取由SRTM DEM派生的流域、海拔、坡向属性,分析冰湖的时空分布与变化特征,探讨影响该区冰湖演化的因素。研究表明:1目前该区共有冰湖1147片,总面积101.63 km2。近20年冰湖总体数量增多、面积增大。2冰川侵蚀湖与冰碛阻塞湖对气候变化的响应不同。3随着气温升高,冰川侵蚀湖水量盈亏峰值上升至更高海拔,冰碛阻塞湖变化愈不稳定。4西风环流对该区冰湖影响深远,偏西向坡面降水量充足,故偏西向冰川侵蚀湖总体变化量小,而偏西向冰碛阻塞湖则在收入持续大于支出的情况下不断扩张。5相对于中国西部其他高山高原区,该区海拔低,冰湖对气候变化响应十分敏感,各空间单元中冰湖收入与支出水量多少受气温升高与降水减少幅度的影响大。

Glacial lakes of the Altay Mountains in China during the past 20 years were interpreted and classified based on the remote sensing images of Landsat TM(1992)/ETM+(2002)/OLI(2013) respectively, with properties including basin, altitude and slope gained from SRTM DEM by spatial overlay analysis in GIS. The features of temporal-spatial distribution and variation of glacial lakes during 1992-2013 and factors which impacted the evolution of glacial lakes in this area were discussed. The results indicate that:(1) there were 1147 glacial lakes in the Altay Mountains of China in 2013, with a total area of 101.628 km2, and both the number and area of glacial lakes increased during the past two decades.(2) The responses of ice-scour lakes and moraine-dammed lakes to climate change were totally different.(3) With temperature rising, the peak of profit and loss of ice-scour lakes reached a higher altitude, and the variation of moraine-dammed lakes became more unstable.(4) Westerly circulation had a significant influence on the glacial lakes, the precipitation on the west-facing slope was sufficient, therefore the west-facing ice-scour lakes varied little, while the west-facing moraine-dammed lakes kept expanding as the profit constantly overmatched the loss.(5) Owing to the lower elevation, glacial lakes in this region were sensitive to climate change than other alpine-plateau areas in western China over the past two decades, both surplus and deficit of water were of high quantity, resulting in few net increment after lake water balance.(6) The magnitude of temperature rise and precipitation reduction during 1992-2002 were larger compared with the period 2002-2013,and the quantity of water surplus and deficit of glacial lakes in spatial units of each size was greater compared with the 2002-2013 period. There is a positive correlation between water surplus and deficit of glacial lakes and the range of temperature rise and precipitation reduction.