Satellite-based alpine water dynamics response to climate change across the Tibetan Plateau

• From 1990 to the 2020 s, LA and lake quantity both increased rapidly across the TP, while MA showed a trend of decline. TWS showed a trend of reduction across the TP. • However, TWS presented statistically significant increase in the Inner Plateau, where lakes are most concentrated and MA presented significant decrease. • As a result of climate change, more land surface water resources have been concentrated in water bodies, and marshlands have shrunk. The spatiotemporal water dynamics across the Tibetan Plateau (TP) are important for sustainable utilization and management of water resources in Asia, particularly in the background of climate change. However, comprehensive analysis of the long-term variations in lakes, marshlands, and terrestrial water storage (TWS) on the TP is lacking. This study utilized a long-term series of Landsat images of the TP to create annual lake maps with 30-m spatial resolution for the period 1990–2022, using a surface water frequency algorithm and Google Earth Engine (GEE). Based on the derived maps, the spatiotemporal trends of marshland area (MA) were analyzed. Using GRACE data products, we investigated and analyzed TWS across the TP from 2002 to 2022. Finally, we analyzed the causes of the changes in lake area (LA) and TWS quantitatively. From 1990 to the 2020s, LA and lake quantity both increased rapidly, with the increase occurring predominantly in the Inner Plateau, whereas MA showed a decreasing trend during 1990–2020, also primarily in the Inner Plateau. Although TWS showed a trend of reduction across the TP, it presented statistically significant increase in the Inner Plateau, which is the region with the highest concentration of lakes. Increase in precipitation and decline in surface water evapotranspiration were the primary reasons for the increase in LA and TWS in the Inner Plateau. The dataset and findings of this study could assist both the government and the general public in confronting the escalating challenges regarding water resources and water security in China.