1961-2020年西南地区干旱特征的时空演变OA

To reveal the spatiotemporal evolution patterns of drought characteristics in southwest China,this study selects the standardized precipitation evapotranspiration index(SPEI)as the drought indicator based on CHM_Drought dataset.Wavelet analysis and run theory were employed to analyze the spatiotemporal dif-ferentiation patterns of multidimensional drought features in southwest China from 1961 to 2020.The results indicate that the drought frequency in southwest China was 13.3%,with 2009 being the most severe drought year,and Guizhou Province exhibiting the highest drought frequency.Drought variations followed 18-year and 3-year principal cycles,suggesting a long-term drying trend and short-term wetting trend in the region.Regional droughts were predominantly mild to moderate,with relatively severe drought events in spring and autumn.Frequency of drought months showed a higher incidence in the east than in the west,while duration was greater in the west than in the east.High-intensity drought zones concentrated in north-west Sichuan and north Guizhou.Regional droughts presented a significant spatial differentiation pattern.Yunnan Province experienced frequent extreme droughts in summer and autumn;Guizhou suffered from se-vere drought events in summer and winter;Sichuan exhibited severe spring droughts;Chongqing demonstra-ted balanced seasonal drought patterns;and Tibet Autonomous Region faced prominent risks of cold-season extreme droughts.Precipitation exhibited the most pronounced effect on regional drought,with seasonal droughts primarily determined by temperature,precipitation,and total radiation.