Changes and variations of the terrestrial water storage anomaly over the core area of the Silk Road

Terrestrial water storage (TWS) plays important role in the food supplies, human and ecosystem health in the world, especially in the arid regions. Therefore, in this study, the changes and variabilities of the TWS anomaly (TWSA) derived from the Gravity Recovery and Climate Experiment (GRACE) satellite dataset are explored over the arid regions of Central Asia during 2003 2014. The total monthly TWSA is decomposed into long-term, seasonal and residual components by the Seasonal Trend decomposition using Loess (STL) method. The linear trends of the long-term components are analyzed in time and space to reveal the spatiotemporal features of the monthly TWSA. To address the dominant spatial mode of the TWSA, the empirical orthogonal function (EOF) method is employed for the monthly TWSA. The major results show that the arid regions of Central Asia have experienced a significant terrestrial water depletion with the rate of - 0.44 mm/month based on the long-term component of the monthly TWSA in 2003 2014. Among the four seasons, spring has the largest TWS caused by the increased snowmelt water with the more precipitation and warm climate. The smallest TWS is detected in autumn. For the spatial features of TWSA, the water depletion centers appear in the small part areas of southwestern Kazakhstan (KAZ), part areas of northwestern Uzbekistan (UZB) and Turkmenistan (TKM). While the increasing linear trends mainly appear in southern Tarrim basin and Kunlun Mountain, and part areas of northeastern KAZ. These spatial variations are consistent with the EOF result. This preliminary investigation in the TWS variations is valuable for scientists and decision-makers in formulating scientifically based approaches and policies for water resource management over the arid regions of Central Asia.