Spatiotemporal patterns and driving mechanisms of evapotranspiration in China simulated by the Priestley–Taylor Jet Propulsion Laboratory model

Evapotranspiration (ET) serves as a critical nexus in Earth’s energy and water cycles and significantly influences climate change, water resource management, and ecosystem health. The spatiotemporal patterns of terrestrial ET across China reveal the complex interactions between climate change and land surface processes. In this study, terrestrial ET across China was simulated from 1982 to 2022 using the Priestley–Taylor Jet Propulsion Laboratory (PT-JPL) model. The model outputs were validated at multiple scales using flux tower observations and four widely recognized remote sensing datasets. The spatiotemporal variations and driving mechanisms of ET across different climatic regions in mainland China were analyzed through structural equation modeling and integrated analysis of climatic and vegetation data. The results show the strong applicability of the PT-JPL model in China, with R2 > 0.9 at flux tower sites and consistent spatial patterns and significant increasing trends (p < 0.01) compared with those of multiple ET products. Over the past four decades, ET has gradually increased from northwestern to southeastern China, and ET was most sensitive to temperature and solar radiation. Relative humidity(RH) and the leaf area index(LAI) were identified as the dominant factors influencing ET variations. The drivers of ET varied markedly among the climatic zones, reflecting complex interactions between regional climatic conditions and vegetation characteristics. These findings provide scientific insights for hydrological resource allocation and climate change adaptation strategies in China while offering valuable guidance for improving the performance of ET models and expanding their applications in diverse climatic regions.