Changes in Evapotranspiration in China During 1980–2024 and the Possible Mechanisms in the Warming Climate

Terrestrial evapotranspiration (ET) plays a vital role in the water cycle, comprising components such as transpiration, interception loss, bare-soil and open-water evaporation, etc. This study has validated the GLEAM (Global Land-surface Evaporation: the Amsterdam Methodology) product with eddy covariance ET data. The spatiotemporal variations in total ET and its components in China during 1980–2024, derived from the GLEAM model, and their relations with air temperature, precipitation and solar radiation in the context of climate change have been studied. During the study period, a significant increase in total ET was found over the southeast of China, especially in spring and summer. The different ET components showed somewhat different trends. While transpiration and interception losses increased significantly in humid and transitional zones, bare-soil evaporation declined markedly in humid regions but remained stable or increased slightly in the northwest and the Tibetan Plateau. Precipitation accounts for the largest share of total ET variability in arid regions, whereas transpiration in humid regions shows the strongest association with available energy. In transitional zones and the Tibetan Plateau, total ET reflects the synergistic regulation of both water and energy availability. Recent enhancements in total ET are primarily associated with rising precipitation in the Tibetan plateau and increasing air temperature in transitional zones.