Abstract: Change of the volume of water reserves in the Tianshan Mountains was analyzed using the monthly gravity field data derived from GRACE satellite with Gaussian filter during the period from 2003 to 2010, and the spatial resolution was 1°×1°. Trend analysis was used to analyze the spatiotemporal variation trend of water reserves in the Tianshan Mountains in recent 8 years based on the monthly precipitation data observed by 31 state meteorological stations. Results showed that there was a significant spatial variation of water reserves in the Tianshan Mountains, the volume of water reserves in the eastern and western parts of the mountains was higher than that in the central part. Temporally, there was an obvious seasonal variation of water reserves and precipitation, and their change trends were similar. The growth of water reserves in the mountains was negative during the period from January to March, its minimum value, -21.7 mm•a^-1, occurred in February. The growth of water reserves was positive during the period from April to December, and its maximum value, 29.9 mm•a-¹, occurred in November. However, the volume of water reserves in the Tianshan Mountains was holistically in a decrease trend during the period from 2003 to 2010, it was decreased by 13×108 m³ in recent 8 years, and its average monthly decrease was 4.8 mm. Reduction of water reserves in the Tianshan Mountains was mainly caused by climate warming, aggravation of glacier melt and increase of the volume of irrigation water and domestic water in the piedmont oases.

Key words: GRACE satellite, water reserves, precipitation, spatiotemporal distribution, Tianshan Mountains, Xinjiang