Global warming potentially increases precipitation and intensifies water exchange, thereby accelerating the hydrological cycle. The Tibetan Plateau (TP) is an Asian water tower in which the water budget varies and its anomaly exerts stress on resource availability. Few studies have quantified long-term water budgets across TP owing to scarcity of ground-based observations and uncertainties in remote sensing data. In this study, water budget components (i.e., precipitation, glacial melting [GM], evapotranspiration [ET], runoff, and soil moisture [SM] state) in TP are synthetically estimated for the past three decades. The water budget estimation benefits from a GM-coupled hydrological ensemble modeling, which is forced by nine precipitation products with seven from satellite methods. The results show that the ensemble modeling effectively captures the dynamics of runoff, ET, and terrestrial water storage. The long-term average annual water input (sum of precipitation and GM) was approximately 438 mm, with similar to 4 % contribution from GM, for which the annual ET and runoff take away was approximately 263 and 173 mm, respectively. From 1984 to 2015, the four water fluxes significantly increased with varying rates (2.3 mm/yr, precipitation; 0.9 mm/yr, GM; 1.5 mm/yr, ET; 1.1 mm/yr, runoff), which suggested an accelerating hydrological cycle. Particularly, increasing GM (similar to 5.8 mm/yr) in the Nyainqentanglha Mountains in southern TP induced high-yield runoff (>800 mm). These estimations aid in yielding robust solutions for water management in TP and neighboring regions. The accelerated hydrological cycle implies potential flooding risk and vulnerability of the hydrological system under climate change.

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.