Mechanisms behind evapotranspiration dynamics in the Middle Yellow River Basin: Role of climate and vegetation

Evapotranspiration is a vital parameter in terrestrial water-energy cycles. Investigating the synergistic effects of climate change and vegetation greening on evapotranspiration is crucial for developing sustainable water resource management and vegetation restoration strategies in the region. The present study focused on the Middle Yellow River Basin (MYB) as its research area. Using the PT-JPL model, we simulated and analyzed the spatiotemporal evolution characteristics of regional evapotranspiration (ET) and its components-vegetation transpiration (ETc), canopy interception (ETi), and soil evaporation (ETs) from 1982 to 2018. Through scenario simulation, multiple regression, and PCMCI (Partial Correlation Minimization Conditional Independence) causal analysis, we elucidated the effects of various environmental factors, particularly vegetation greening, on changes in ET and its components. Our research revealed that ET and its components in the MYB from 1982 to 2018 exhibited a distribution pattern characterized by higher values in the south and lower values in the north. Notably, ET and ETc showed decreasing trends, while ETi and ETs displayed increasing trends. Temperature and vegetation greening emerged as the primary driving factors for changes in ET and its components. Specifically, temperature promoted increases in ETs but inhibited increases in ETc and ETi. Vegetation restoration led to a decrease in ETc while simultaneously increasing ETi and ETs. The findings of our study provide a scientific basis and support for decision-making in water resource management and ecological restoration in the MYB.