Delayed onset and intensification of flash droughts under warming scenarios & their association with compound meteorological extremes
摘要
Flash droughts have attracted significant public concern because of the immediate risks they present to food security, ecological safety, and human health. However, a comprehensive assessment of projected changes in flash drought and their association with compound meteorological extremes is limited over India. The present study attempts to answer the following research questions: (i) How do the characteristics of flash droughts change under future climate change scenarios, as predicted by CMIP6 Global Climate Models (GCMs)? (ii) How are the onset dates of the first and last flash droughts likely to change under warming scenarios? (iii) How frequently do Compound Meteorological Extremes (CMEs) occur during flash drought events in historical records? In this study, the pentad mean water deficit index is used to examine the flash drought characteristic by using multivariate bias-corrected outputs from ten GCMs and dynamic potential evapotranspiration using elevated CO2. The analysis reveals a substantial increase in the frequency, duration, and severity of flash droughts in India. In particular, the frequency and duration are expected to increase over the central, northwest, and central regions in India. A pronounced increase in the flash drought characteristics occurs under high emission Shared Socioeconomic Pathway (SSP) scenarios such as SSP3-7.0 and SSP5-8.5. A substantial increase in the spatial and temporal extent of the flash drought is predicted under future climate scenarios. A delayed onset of flash drought is expected across India in the future. In a particular case, the delayed onset occurs over 86% of the total area. The dominance of wind speed-vapour pressure deficit and maximum temperature-wind speed-vapour pressure deficit combinations highlights the growing importance of evaporative stress and atmospheric dryness in the development of flash drought conditions amid a warming climate.