Climate change characteristics of regional drought–flood abrupt alternation events in the low-latitude plateau of southwest China

Drought-Flood Abrupt Alternation (DFAA) refers to an abrupt transition from drought to extreme precipitation (or vice versa) in the same region over a short period of time. As a highly impactful compound disaster, it exhibits greater destructiveness in plateau areas. Currently, there is a lack of systematic research on the sub-seasonal scale characteristics of DFAA changes under global warming. Based on daily precipitation data from meteorological stations on the Yunnan Low-Latitude Plateau, this study constructed a daily DFAA index, identified DFAA events during 1961–2022 using cluster occurrence theory, and explored their spatiotemporal characteristics and future evolution trends using CMIP6 model data and multiple analytical methods. The results show that since 2000, both the frequency and intensity of DFAA events in Yunnan have increased significantly, with the drought-to-flood type showing the most notable increase. High-risk areas were concentrated on the Yunnan-Guizhou Plateau, with a peak period from April to October. Future projections indicate intensified DFAA events, with the average intensity increasing by approximately 0.5 index units and the recurrence interval of extreme events shortening from 50 to 10 years. This study provides a scientific basis for understanding compound hydrological disasters in low-latitude plateau regions.