Research on future climate change and hydrological response in the Luanhe River Basin

Study region: Luanhe River Basin, CHINA Study focus: This study constructed a SWAT model for the Luanhe River Basin and quantitatively assessed the simulation capability of precipitation and temperature in the basin using eight Global Climate Models (GCMs) from the CMIP6 dataset. Climate variable values are derived using a weighted multi-model ensemble approach. Meteorological data are downscaled and bias-corrected using the Delta-DCSI method and an improved Quantile Mapping (QM) method that retains trend signals. Subsequently, the calibrated SWAT model is used to predict changes in runoff, soil water, and evapotranspiration under three Shared Socioeconomic Pathways (SSPs) scenarios for the future. New hydrological insight for the region: As the outlet control station of the Luanhe River Basin, the Panjiakou hydrological station yielded R2 and NSE values exceeding 0.81 during the calibration period (1962–1995) and 0.70 during the validation period (1996–2017), demonstrating the model's proficiency in capturing basin-scale hydrological processes. Consequently, the SWAT model, driven by bias-corrected meteorological data, was employed to simulate hydrological responses under future climate scenarios. The results indicate that projections across the three future scenarios indicate that precipitation and temperature follow an increasing trajectory, despite the presence of sharp interannual fluctuations in precipitation. Runoff, soil water, and evapotranspiration demonstrate fluctuating upward trends with substantial spatial differentiation. The most pronounced changes in hydro-meteorological elements occur under the SSP585 scenario, reaching their maximum increments in the long-term period. Furthermore, runoff, soil water, and evapotranspiration display similar spatial distribution patterns, being higher in the east and south and lower in the west and north.