- 1School of Geoscience and Technology, Zhengzhou University, Zhengzhou, China (jianglijun@zzu.edu.cn)
- 2College of Compute Science and Technology, Qingdao University, Qingdao, China
- 3University of Chinese Academy of Sciences, Beijing, China
- 4National Institute of Natural Hazards, Ministry of Emergency Management of China, Beijing, China
- 5School of Physics, Peking University, Beijing, China
- 6Key Laboratory of UAV Emergency Rescue Technology, China Fire and Rescue Institute, Beijing, China
Research on compound dry and heat wave events (CDHWs) has been limited by inconsistencies in the temporal resolutions of their constituent hazards, with droughts commonly characterized at monthly scales and heat waves at daily scales. The development of daily-scale drought indices enables the identification of dry events on a daily basis, thereby facilitating more detailed investigations of CDHWs. Using daily Standardized Precipitation Evapotranspiration Index (daily-SPEI) data and heat wave records, CDHWs were identified for the period 1961–2020, and their spatiotemporal variations in frequency, duration, dry severity, and heat intensity were systematically analyzed. Extreme CDHWs were further defined based on the upper thresholds of dry severity and heat intensity across all identified events, and changes in their occurrence probabilities, along with the relative contributions of dry events and heat wave events, were examined.
The results indicate a widespread intensification of CDHWs across global land areas, with particularly pronounced increases in western North America, eastern South America, Europe, northern Africa, and parts of Asia. The frequency of CDHWs shows significant upward trends since the 1990s, with a marked acceleration in recent years. Notably, extreme CDHWs exhibit more severe changes during 1991–2020 compared with 1961–1990. Consequently, the return periods of extreme CDHWs have decreased significantly across nearly all global land regions, with reductions exceeding 60% in many areas. Control variable experiments further demonstrate that changes in heat wave events contribute more to the reduction in return periods of extreme CDHWs than changes in dry events, accounting for approximately 23%–63% and 6%–13%, respectively. Overall, this study advances the understanding of CDHWs at daily temporal scales and underscores the need to place greater emphasis on extreme compound events under rapidly intensifying climate conditions.
How to cite: Jiang, L., Zhang, J., Bai, L., Han, J., Meng, X., Cao, D., and Al-Sakkaf, A. S.: Widespread intensification of compound dry and heat wave events at daily scales over global land regions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10891, https://doi.org/10.5194/egusphere-egu26-10891, 2026.
