A dynamic Budyko framework incorporating water storage changes and antecedent precipitation to assess runoff response in typical karst regions

Karst regions, characterized by dual-domain aquifers and rapid water infiltration, pose challenges when applying traditional hydrological models designed for stable catchments. Understanding these dynamics is critical for advancing water resource management in ecologically fragile areas. The traditional Budyko framework fails to capture the dynamic processes at finer temporal scales that are more acute in karst systems. This study addresses this limitation by proposing a dynamic Budyko framework that explicitly incorporates changes in soil water storage, groundwater storage and antecedent precipitation as key drivers of water availability. Through a multi-temporal analysis of eight karst basins in Southwest China (1980–2020), we demonstrated that the modification effectively constrained annual and monthly data within the Budyko domain, particularly resolving the phenomenon where the monthly distributions of ET/P and ET₀/P significantly exceeded the Budyko boundaries. Attribution analysis showed that runoff was most sensitive to rainfall, followed by landscape characteristics and potential evaporation. To further dissect climatic influences, we proposed a ET₀-based dscomposition framework specially isolating meteorological drivers. This secondary analysis demonstrated that relative humidity dominated runoff variation among climatic variables controlling ET₀. Furthermore, the monthly variation of Budyko parameter ω in karst regions exhibited distinct trends compared to non-karst regions, which was likely attributed to region’s unique hydrogeological structures. This study offers an efficient tool for karst systems, enabling the precise separation of climatic and anthropogenic impacts across temporal scales. These findings demonstrate the applicability of Budyko’s theory and provide critical insights into sustainable water management under intensifying climatic extremes.