Reconstructed Evapotranspiration in Northern China: Trends, Drivers, and Ecohydrological Impacts

Attributing regional evapotranspiration (ET) and assessing its impacts are critical for understanding land‐atmosphere interactions in climate‐sensitive regions such as northern China. This study fuses six gridded ET products with in situ measurements using Random Forest after excluding poorly representative flux sites. The resulting monthly 0.25° dataset (1980 to 2021) outperforms all original products, reducing the cross‐validation RMSE from 15.15–22.03 mm month −1 to 11.54 mm month −1 . Based on reconstructed ET, significant increasing ET trends ( p < 0.05) are observed on the Loess Plateau and North China Plain, with a mean trend of 13.3 mm (10a) −1 in humid regions. Using XGBoost with SHAP analysis reveals that precipitation dominates ET interannual variability in grasslands and bare lands, accounting for 35.4% to 40.6%. Yet, as a driver of the long‐term ET trend, precipitation is dominant only in about 5% of the region, specifically over bare land in western Inner Mongolia. Instead, NDVI drives ET trends over 52% of northern China, making vegetation greening a primary force enhancing ET under warming. Enhanced ET offsets precipitation‐driven water yield gains most markedly in semi‐arid regions. There, the ET‐induced reduction reaches −11.4 ± 7.7 mm (10a) −1 , exceeding the positive contribution from precipitation (2.3 ± 9.2 mm (10a) −1 ). Meanwhile, ET positively contributes to the Evaporative Stress Index (ET/PET) over semi‐arid regions, generating a coexistence of ecological wetting but hydrological drying. This study provides ecological insights into ET changes and their contrasting hydrological impacts in climate‐sensitive regions.