Changes in Terrestrial Water Storage During 2003–2014 and Possible Causes in Tibetan Plateau

The spatial‐temporal changes in terrestrial water storage (TWS) over the Tibetan Plateau (TP) and six selected basins during 2003–2014 were analyzed by applying the Gravity Recovery and Climate Experiment data and the extended Variable Infiltration Capacity‐glacier model, including the upstream of Yangtze (UYA), Yellow (UYE), Brahmaputra (UB), and Indus river basins and the Inner TP and the Qaidam Basin. The possible causes of TWS changes were investigated from the perspective of surface water balance and TWS components through multisource data and the Variable Infiltration Capacity‐glacier model. There was a strong spatial heterogeneity in changes of Gravity Recovery and Climate Experiment TWS in the TP—with apparent mass accumulation in central and northern TP and a sharp decreasing trend in southern and northwestern TP. The TWS changes in the TP were mostly attributed to variations in precipitation and evapotranspiration from the perspective of land‐surface water balance. Precipitation played a dominant role on the TWS accumulation in the UYA and UYE, while evapotranspiration had a more important role than precipitation in TWS depletion in the UB. From the perspective of TWS components, the TWS increase in the UYA and UYE was mainly caused by an increase in soil moisture, whereas the decrease in TWS in the UB was mostly due to glacier mass loss. TWS was accumulating from March through August in southeastern TP while from November to April/May in northwestern TP. The seasonal variations of TWS are highly modulated by the large‐scale climate system, atmospheric moisture flux, and precipitation regime over the TP. Key Points Precipitation played a dominant role in TWS increases in the UYA and UYE, whereas ET had a more important role in TWS depletion in the UB The increase in TWS in the UYA and UYE was dominated by soil moisture increase; the decrease in TWS in the UB was due to glacier mass loss Seasonal variations of TWS were highly modulated by large‐scale climate system, atmospheric moisture flux, and precipitation regime over TP