SPATIAL AND TEMPORAL EVOLUTION CHARACTERISTICS OF DROUGHT-FLOOD ABRUPT ALTERNATION IN GUIZHOU PROVINCE IN RECENT 50 YEARS BASED ON DWAAI INDEX

Based on the daily rainfall data of 19 meteorological stations in Guizhou Province from 1968 to 2017 and combining the characteristic of hydrogeology in Guizhou Province, this study revised the Dry-Wet Abrupt Alternation Index (DWAAI) and analyzed the spatial and temporal evolution characteristics of drought-flood abrupt alternation in Guizhou Province in recent 50 years. The results show that: 1. the revised DWAAI index has good applicability in Guizhou Province; 2) The time of drought-flood abrupt alternation is mainly distributed from April to October. In terms of the interannual variation, the station proportion and intensity show an increasing trend, and the increasing trend was significant in station proportion. The intensity of drought-flood abrupt alternation in autumn shows a decreasing trend, and the station proportion and intensity increase in other seasons, in which the intensity of the drought-flood abrupt alternation in spring and summer and the station proportion of the drought flood abrupt alternation in summer increase significantly. (3) The frequency of the drought-flood abrupt alternation in Guizhou Province decreased from east to west as a whole. It is easy to occur in spring in the south, in summer in the middle and the north with the largest area, and in autumn in the east. With the increase of the years, the scope of prone areas has been expanding The results are of great significance for disaster prediction and early warning and drought and flood control in this area.