Anthropogenic Speeding Up of South China Flash Droughts as Exemplified by the 2019 Summer-Autumn Transition Season

摘要

The emergence of flash drought has raised widespread attention due to its rapid development and devastating impacts, but whether climate change affects its evolution and intensity is still elusive. Here, we investigate a severe flash drought event that fully developed over South China within a month in August 2019 and persisted until November. It has a 1-in-229-year rapid onset speed and 1-in-80-year large intensity due to strong cyclonic anomaly over western North Pacific and persistent local geopotential height anomaly. The attribution based on the latest Coupled Model Intercomparison Project Phase 6 (CMIP6) data shows that anthropogenic climate change has increased the likelihood of onset speed and intensity of the drought event by 24 ± 16% and 37 ± 9%, respectively, which is closely related to anthropogenic temperature increase and precipitation decrease. Our study implies that anthropogenic climate change accelerates the drought onset speed and increases the challenge for drought adaptation.