Flash Drought Occurrence across the Globe

Flash droughts can lead to devastating impacts on agriculture, short term water resources, and ecosystems. Furthermore, flash drought can transition into longer term drought, such as hydrological or socioeconomical drought, which may lead to economic collapse, destabilization of governments, and an increased risk of conflict and war in under-developed countries. With a rapidly growing interest in understanding fundamental characteristics of flash drought and its associated impacts, it is vital to identify where flash droughts are most likely to occur across the globe. This study provides a global climatology of flash drought occurrence by utilizing the standardized evaporative stress ratio (SESR). A flash drought identification methodology using four criteria was employed across four global reanalysis datasets: the Modern-Era Retrospective analysis for Research and Applications (MERRA), MERRA Version 2 (MERRA2), ERA5, and ERA-Interim. The mean of flash drought occurrence among the four datasets is calculated, as well as the variability between the reanalyses. In addition, the temporal distribution of flash drought development is analyzed for spatial hot spots in flash drought frequency across the globe.