Loss of terrestrial water storage in the Tianshan mountains from 2003 to 2015

The Tianshan Mountains region in Central Asia is covered with a large mass of glaciers and seasonal snow cover. This region supplies the main freshwater resources for Central Asia but has been severely affected by climate change over the past decades. In this study, we use the Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) datasets to analyze the spatiotemporal variability of the terrestrial water storage (TWS) in the Tianshan Mountains from 2003 to 2015. The analysis shows that the TWS in the Tianshan Mountains has declined during the past decade. Seasonal changes in the water storage are caused by seasonal differences in the combined precipitation and temperature conditions. The results of TWS variations (TWSVs) in the Tianshan Mountains in 2003-2015 indicated that there is a declining rate of the TWS of the TWS-Mascon, TWS-Gaussian, and TWS-Noah is -0.72, -0.48, and -0.41 cm year(-1), respectively. This suggests that the water storage loss in Tianshan Mountains has been about -4.32 x 10(9), -2.88 x 10(9), and -2.46 x 10(9) m(3) year(-1) during 2003-2015, respectively. Glaciers and seasonal snow cover shrinkage obviously are the main factors governing the spatial difference in the TWSV. Annual mean temperature stays in a high state from the mid-1990s has been a predominant factor affecting the TWSV in the mountains during the past decade. A significant temperature increase in the middle region (Chinese part) accelerated the glacier and snow-cover shrinkage, which resulted in TWS loss.