Characteristics of compound high temperature and drought/rainfall events in China from 1982 to 2022

With global warming, the occurrence characteristics of compound climate events have gradually become a research hotspot in recent years. Compared to compound high temperature and drought events, research on compound high temperature and rainfall events is relatively lacking, which limits our understanding. Therefore, this study analyzed the occurrence characteristics of compound high temperature and drought/rainfall events in China from 1982 to 2022 using daily maximum temperature and daily precipitation data from the European centre for medium-range weather forecasts (ECMWF) global climate atmospheric reanalysis (ECMWF Reanalysis v5, ERA5). A magnitude index was introduced to measure the intensity of compound events. The results indicate that the duration, frequency, and magnitude of these compound events all show varying degrees of increase, with the growth rate of compound high temperature and rainfall events (CHTRE) being higher than that of compound high temperature and drought (CHTDE). The upward trends for CHTDE and CHTRE are particularly significant (0.24% and 0.11%, respectively), with high temperatures dominating the variation trend of compound events. June, July, and August are the primary months for the occurrence of CHTDE and CHTRE in China, with extreme compound events predominantly concentrated in July. This study aims to more comprehensively examine the occurrence characteristics of the two types of events. This research explored the contributions of high temperature and rainfall to the composund events, investigates the differences in the mechanisms of the compound events, and briefly analyzes the robustness of the compound event results under different threshold selections. Given that extreme events may increase with ongoing global warming, understanding the occurrence characteristics of compound events is crucial for enhancing China’s capacity to withstand the impacts of climate change.