Geographical heterogeneity in the evolution of meteorological drought under climate change: Differential responses of karst and non-karst geomorphologies in southwest China

Meteorological drought significantly affects water resources, agriculture and ecosystems in Southwest China, and in-depth research is crucial to achieving sustainable development in the region. The aim of this study is to investigate the spatial and temporal distribution characteristics of meteorological drought and its evolutionary trend in karst and non-karst areas, and to reveal the pattern of drought occurrence and development under different geological and geomorphological conditions by comparatively analyzing the differences between the two regions. The temporal-spatial evolution characteristics of karst and non-karst areas were explored by using aridity index (AI), potential evapotranspiration (ET ₀ ) and standardized precipitation evapotranspiration index (SPEI), and the differences of drought severity (DF) and drought intensity (MDI) were clarified. The results showed that the distribution of humid climatic zones was more concentrated in the karst region, and the mean annual aridity index was higher, indicating a wetter climate than in the non-karst region. Karst regions are wetter in spring and winter, while non-karst regions are wetter in summer. In addition, the severity and intensity of drought were higher in the karstic regions than in the non-karstic regions, especially in Guizhou, Chongqing and Guangxi regions. These differences may be related to the unique geological and geomorphological features of karst regions, such as shallow soil layers and complex karst landscapes, which affect water retention and circulation and make karst regions more sensitive under drought conditions. The study offers a scientific basis for targeted drought prevention and ecosystem management, emphasizing the need for further research on meteorological drought impacts on diverse ecosystems to address climate change challenges.