Response of alpine runoff to the ‘Warming and Wetting’ climate change trend: a Budyko-based attribution analysis in the Daheba Basin

ABSTRACT Understanding runoff responses in al pine basins is essential for water-resource management under climate change. This study assessed runoff changes and their drivers in the Daheba Basin, northeastern Tibetan Plateau, using hydrometeorological and land-surface data for 1980–2023. Methods included Sen’s slope estimation, the Mann–Kendall test, cumulative anomaly analysis, and Budyko-based attribution. Runoff increased insignificantly by 0.54 mm/year, while precipitation, annual mean air temperature, and potential evapotranspiration increased significantly by 1.57 mm/year, 0.015 °C/year, and 0.46 mm/year, respectively, indicating warming and wetting. Abrupt-change analysis identified 2004 as the key shift year, separating the baseline (1980–2004) and change (2005–2023) periods. Runoff depth, precipitation, temperature, and potential evapotranspiration were higher in the change period, whereas the dryness index (ET0/P) declined from 1.64 to 1.49, indicating wetter conditions. Budyko-based attribution showed that climate forcing dominated estimated runoff variation, with precipitation as the primary driver. Contributions from potential evapotranspiration and the residual effect associated with changes in integrated catchment characteristics were comparatively small. These findings clarify hydrological responses in climate-sensitive alpine basins and inform water-resource management and ecological protection on the Tibetan Plateau.