Glaciers and lake changes (1968-2013) and their causes in the Songmuxi Co Basin, Northwest Tibetan Plateau
The Tibetan Plateau and its surroundings contain the largest number of glaciers outside the Polar Regions and are known as the world's "third pole".Glacial and lake changes in the third pole not only lead to changes in atmospheric circulation patterns in the region and the northern hemisphere but also affect agriculture, power generation and the water supplies of 1.5 billion people in the surrounding areas across ten countries.Hence, the situation of the glaciers and lakes of the third pole has attracted attention worldwide.While the Himalaya glaciers are largely retreating, the recent evolution of the Karakoram glaciers, widely acknowledged as peculiar, remains poorly understood.Glacial lakes showed a trend of expansion and the great lakes were shrinking in the Himalayas;but lakes in the Karakoram were considered stable.The causes and mechanisms of the complex and regionally heterogeneous behavior of glacier and lake change between the Karakorum and Himalayas are poorly understood.The Songmuxi Co Basin lies in the transitional zone between the Karakorum and Himalayas, and the glaciers and lakes have a significant impact on the local water supply and ecosystem.In this work, glacial and lake changes in the Songrnuxi Co Basin, southern Karakoram Mountains were detected based on 1:50000 topographic maps, Landsat MSS/TM/ETM +/OLI remote sensing data and GIS techniques.The annual temperature, precipitation, potential annual evaporation at Shiquanhe, Hetian and Yutian stations from 1968 to 2013 were used to analyze climate change and its impact on glaciers and lakes area change.The results can be drawn as follows.(1) From 1968 to 2013, the total glacier area decreased from 139.25 km2 to 137.27 km2, a total loss of 1.98 km2, or 1.42％ of the entire glacial area in 1968.In addition, there has been an accelerating trend of glacier retreat since 2001.(2) The area of Songmuxi Co expanded from 25.05 km2 in 1968 to 32.62 km2 in 2013.The overall increase was 7.57 km2, which was 30.22％ of the lake area in 1968.The lake area expansion and glaciers retreat have a good coupling on a decadal scale.(3) From 1968 to 2013, the decreased potential evapotranspiration in the lake and increased precipitation are of the first and second factors which lead to lake area expansion.The increase in melt water from glaciers and frozen soil due to climate warming had no great impact on lake area expansion on the interannual scale while it may had some impact on the decadal one.
NETL
NSTL
万方数据
维普
