Characteristics of spatio-temporal changes in flash droughts based on the CMIP6 Model

Flash droughts (FDs) are rapid droughts that occur over a short period caused by severe heat waves and precipitation deficiency. FDs have critically increased impacts on agriculture and natural ecosystems. We used the standardized evaporative stress ratio (SESR) to identify FDs during the growing season in a historical simulation and under 4 future shared socio-economic pathway scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5) of the CMIP6 model based on actual and potential evapotranspiration. Arid regions were classified based on the aridity index (AI), and the frequency, duration, and intensity of FDs were compared and analyzed for different arid regions under different future scenarios. The results showed significant regional differences in global FD events, where the frequency was 10~30%, and the duration was primarily 30~35 d in most areas. FD intensity was mainly moderate, and severe FDs and ranges of FDs under the 4 future scenarios were similar. In addition, the frequency and duration of FDs were slightly higher in humid regions under different scenarios. The proportion of different FD intensities in humid regions was much higher than in other arid regions. Finally, FD regions were divided into Governance, Concern, and Prevention Areas based on the overlayed FD characteristics under the 4 future scenarios, contributing to regionally varied approaches and solutions for the response and prevention of drought disasters.