Water Balance Shifts Induced by Multiyear Drought Within the Budyko Framework

Abstract

AbstractClimate change intensification can induce unprecedented alterations to global hydrological cycling. This study employed the Budyko framework to assess water balance shifts induced by resultant multiyear drought events, selecting 1,258 among 3,347 globally distributed catchments. Here, the precipitation (P) deficit was used to identify long‐term drought, while the Budyko framework was used to explore the impact of long‐term drought on changes in streamflow (Q). Additionally, this study developed a novel method (the trigonometric function decomposition method (TFD method)) to analyze Q change induced by climate and catchment properties changes. Results showed that: (a) long‐term drought has caused catchment property parameter (n) increase (i.e., n is 2.14 and 2.33 during non‐drought period and drought period in 1,258 catchments, respectively), which will alter P partitioning into E and Q; (b) sensitivity analysis presented n is most sensitive to changes in aridity index, while effective rooting depth (Ze) contributed larger magnitude in variability of n; (c) a reduction in the magnitude of Q decreased under a reduction in climatic aridity, which were primarily controlled by climate changes (average value, 80.83%), while asymmetrical effects of Q reduction were induced by catchment property changes and suggested Q reduction were weakened in arid and humid regions, while strengthened in semi‐arid and sub‐humid regions. Together, these factors all indicated that multiyear drought events can significantly alter Q, while the hydrological response to drought events was characterized by complex mechanisms. Clarifying the hydrological response to multiyear drought events will help us better understand how climate change affects water resources.