Variation characteristics of water reserves in high mountains and surrounding areas in Arid Central Asia

Arid Central Asia. We investigated 2003–2021 trends in air temperature, precipitation, and evapotranspiration (ET) across Arid Central Asia and its high-mountain regions. Using terrestrial water storage derived from GRACE, we applied robust trend analysis and significance testing to quantify spatiotemporal variability at monthly, seasonal, and interannual scales. We further revealed contrasting terrestrial water storage responses in high-mountain areas and adjacent representative subregions under both co-directional and counter-directional changes in the climate driving and ecological vegetation regulation. This work provides new insights into the variability of terrestrial water storage anomalies across multiple time scales in arid Central Asia and in high elevation regions that function as inland water towers. We use terrestrial water storage derived from GRACE together with reanalysis products. Under regional warming, explanations of mountain terrestrial water storage that rely only on precipitation and evapotranspiration are insufficient, because abundant runoff from snow and glacier melt prevents a clean closure of surface and subsurface water budgets. GRACE offers an integrated, observation based measure of all water compartments and therefore adds a valuable large scale perspective. We find a marked decline of terrestrial water storage in the Tianshan Mountains of −11.13 cm/a, whereas the Kunlun and Qilian Mountains ranges show increases of 7.81 cm/a and 5.18 cm/a, respectively. A comparison of the Oases located in the Hexi Corridor and the Tarim Basin as defined in this study indicates that human activities do not always deplete water resources. With sound planning and effective institutions, well designed interventions can enhance watershed water retention and storage capacity. • Arid Central Asia and its high mountains warm > twice the global average, with the Qilian Mountains warming fastest. • Satellite gravity data reveal monthly/seasonal/annual water storage variations in the region; Kunlun and Qilian Mountains show increasing storage. • Mountain water storage is a key part of arid Central Asia’s water resources and exerts far-reaching impacts region-wide.