Atmospheric Rivers Sustain and Reshape Hydrological Responses Across Chinese River Basins

Abstract Atmospheric rivers (ARs) are key drivers of hydrological change, but their role in sustaining and reshaping hydrological responses in Chinese river basins remains insufficiently quantified. We detect ARs for 1950–2023 using integrated water vapor transport (IVT) dual percentile thresholds with morphological filtering for elongated, persistent features; attribute precipitation, extreme precipitation, runoff, and soil moisture via a 1.5° axis buffer; model contributions with zero‐inflated beta (ZIB) regression; and trace moisture sources during AR‐driven floods with TROVA. Results reveal a south‐to‐north contrast, with southern basins exhibiting high summer IVT (∼600–1,100 kg m −1 s −1 ) from long ARs (∼13,000 km) that sustain antecedent wetness and amplify floods, while since the 1980s ARs have shortened and weakened, and hydrologic responses have declined in central and northern basins. Basin mean ARs contributions peak in the Huai River Basin (16.5%, 70.0%, 17.9%, 3.2%) and are lowest in the Southwest Basin (0.1%, 0.8%, 0.1%, 0.04%) for precipitation, extreme precipitation, runoff, and soil moisture, respectively. ZIB indicates a declining mean AR influence on soil moisture in the east and increasing shares of extremes in the southeast; antecedent soil moisture is the strongest covariate of AR‐induced precipitation. During floods, dominant sources can reach 74.7% from the East Asia Monsoon (Yangtze River Basin, 1998), 55.6% from the West Pacific Tropics (Pearl River Basin, 2009), and 32.5% from the South Asia Monsoon (Pearl River Basin, 1985). These findings show that ARs sustain water availability and reshape hydrological responses, informing flood risk management and water security planning in a warming climate.