关键词: 全球变暖, 降水蒸发, 冰川, 新疆, 水循环

Abstract: Xinjiang Uigur Autonomous Region is located in the northwest of China.The special topographic conditions,which is known as "Two basins lie in between three mountains",and the droughty climate create the unique water cycle in the region.With a large number of mountain glaciers in the middle-latitude regions in the world,Xinjiang has an abundant glacial runoff,which is an important factor of the local water cycle and has significant contribution to the local climate and river runoff.As the global climate is getting warmer and warmer,the precipitation,glaciers,runoff of rivers and underground water in Xinjiang Region have undergone great change since the middle 1980s,with an increasing precipitation and a continuously increasing temperature.As a most sensitive sensor of the climatic changes,the glaciers in mountainous regions of Xinjiang Region are thinning and retreating,while the meltwater is increasing.Statistics show that negative mass balance dominates in the Glacier No.1 at river sources of Ürümqi.There is an obvious increase in the average annual runoff in most rivers of Xinjiang Region.Water level increases and surface area multiplies in many lakes and the underground water level rises in some areas. According to the observations at hydrometeorological stations in Xinjiang Region,surface evaporation,which plays a significant role in the water cycle of Xinjiang Region,is decreasing on the whole.So the import of vapor from other countries has to do with an extra precipitation.The acceleration of global water cycle,which is induced by global warming,causes an increase of vapor content in atmosphere.This accounts for the change of precipitation in the past decade in Xinjiang Region. In the model of internal water cycle of Xinjiang Region,one supreme change is the accelerating melt of glaciers,which is a significant contribution to the increase of runoff of rivers,lakes and underground water.The accelerating melt of glaciers is gradually destroying the vulnerable balance of water cycle in a basin and will cause water deficiency in Xinjiang Region consequently and thus aggravate flood disasters. Through the analysis of the change of water cycle in Xinjiang Region in the recent years,this paper concludes that the growth of precipitation in Xinjiang Region is mainly caused by the acceleration of water cycle in the worldwide range.It is revealed from the analysis that the continuously warming global climate will magnificently impact the water resources in Xinjiang Region.

Key words: global warming, precipitation and evaporation, glacier, Xinjiang Region, water cycle