A new drought characteristic, i.e., the duration of drought onset is proposed to depict how rapid drought develops. The roles of pre-drought and post-drought high temperatures on drought onset are quantified. High temperatures behave differently among areas with different vegetation conditions.

In this study, three machine learning methods displayed a good detection capacity of flash droughts. The RF model was recommended to estimate the depletion rate of soil moisture and simulate flash drought by considering the multiple meteorological variable anomalies in the adjacent time to drought onset. The anomalies of precipitation and potential evapotranspiration exhibited a stronger synergistic but asymmetrical effect on flash droughts compared to slowly developing droughts.

7 CMIP5 climate models under RCP8.5 emissions scenarios were downscaled by means of bilinear interpolation and bias correction. The downscaled results are evaluated over China by comparing with the England Reanalysis CRU3.1. Time series of SPI has been used to identify drought from 20th century to 21st century over China. the SPI show a slightly increasing trend in the future period for the most parts of China, but drought in Southwest region of China will become the norm in the future.