Study on Water Storage Change and Its Consideration in Water Balance in the Mountain Regions over Arid Northwest China

摘要

Changes in permafrost and glaciers influence water balance in mountain regions of arid northwest China. Terrestrial water storage change (TWSC) is an important factor in thewater cycle. In this study,we usedGravity Recovery andClimate Experiment (GRACE) satellites data to retrieve the TWSC in Tien Shan and Qi Lian Mountains. Variation of seasonal TWSC was obvious. However, the seasonal and annual differences reflected the imbalance of water resource distribution in two mountains. The TWSC decreased in the Tien ShanMountains but increased in the Qi LianMountains during 2003 to 2010. Permafrost and glaciers play an important role in the water cycle in aridmountain regions.Demands for water for agriculture need more groundwater extraction for irrigation and glacial melt feeding the rivers which leads to the state of loss of TWSC in Tien ShanMountains. Increase and thickening of the active layer of permafrost could lead to more infiltration of surface water into the groundwater, which result in increasing water storage and changes in the regional water balance. According to water balance, precipitation and evaporation changed little in short time, and TWSC changed obviously, whereas runoff showed an increasing trend in the Tien ShanMountains and a decreasing trend in the Qi Lian Mountains.