Study on spatio-temporal evolution characteristics of meteorological drought and its risk in China based on SPI-RRV index

To fully reveal multi-dimensional meteorological drought characteristics in China under changing environment, an SPI-RRV index-based drought risk assessment method was put forward by coupling the meteorological drought index(SPI) and the reliability-resilience-vulnerability(RRV) index to assess spatio-temporal evolution characteristics of meteorological drought and the drought risk in China. The results show that the SPI-RRV index has characteristics of high stability and strong spatio-temporal comparability, and can accurately assess spatio-temporal evolution characteristics of meteorological drought risk. The average drought grid ratio, proportion of drought months, and number of drought events in southem China are larger than those in northem China. Droughts in humid and semi-humid regions have higher intensity and shorter durations, while droughts in semi-arid and arid regions have lower intensity and longer durations. The transfer of high drought risk areas has a significant interdecadal variation pattern, with a transferring trend from northwest to southwest.