Groundwater drought propagation and the drought resistance capacity in different climatic regions of China

Comprehensively understanding the interactions between different drought types is important for implementing effective drought warnings. However, recent research has focused mainly on propagation among meteorological drought (MD), hydrological drought (HD) and agricultural drought (AD), with a lack of groundwater drought (GD) propagation research. Therefore, this study focused on GD, and the characteristics of MD, AD, and AD in different climatic regions of China were evaluated. The conditional probability was employed to determine the drought propagation threshold under the MDADGD propagation path, and the dynamic changes in drought propagation thresholds were analyzed to reveal the spatial difference in drought resistance capacity. Finally, the main factors influencing GD were analyzed. The results indicated that (1) the soil water system in Northeast China, the QinghaiTibet Plateau and northern Northwest China exhibits high drought resistance for MD. Moreover, the groundwater system in Northeast China, North China and the QinghaiTibet Plateau exhibits notable drought resistance for AD. (2) The propagation threshold for GD in most areas is decreasing, indicating a decreasing trend of GD resistance capacity in most areas, posing greater challenges to GD mitigation. (3) Deep soil moisture provides an important buffer zone, and its variation affects GD. However, in areas rich in hydrothermal resources, the water deficit represented by precipitation and evaporation may play a more important role. The results of this study are helpful for understanding the drought propagation process and formulating drought prevention and mitigation policies.