基于不同干旱指数的江西省干旱时空特征和成因分析OA

Under the background of global warming,the frequency and intensity of regional drought events are increasing,posing greater challenges to the monitoring and forecasting of droughts.To compare the applicability of different meteorological drought indices in Jiangxi Province,this paper introduces three different meteorological drought indices:the Standardized Precipitation Evapotranspiration Index(SPEI),the Daily Evapotranspiration Deficit Index(DEDI),and the Meteorological Drought Composite Index(MCI).Moreover,the spatiotemporal distribution characteristics and causes of drought events in Jiangxi Province are also analyzed through these indices.Results indicate that while the overall trends of the drought characteristics calculated by the three indices are similar,MCI effectively identifies the typical drought years with disaster records in Jiangxi Province and is more sensitive to extreme drought events.The seasonal variation of drought shows a characteristic of the highest frequency in autumn,followed by summer and winter,and the lowest in spring,but the drought zones reflected by different indices are different.The diagnostic analysis of typical drought events indicates that SPEI sometimes exhibits unreasonable interruptions of prolonged drought periods.MCI shows a more pronounced response to significant drought events,although the occurrence of extreme values is slightly delayed compared to SPEI and DEDI.In addition,the drought index regression of the circulation background field revealed that the drought events in Jiangxi Province in autumn are related to factors such as the stability of the subtropical high,the intensity of the polar front jet and subtropical jet,and the low-level moisture transport belt.A stable and strong subtropical high with a westward and northward position,a stronger(weaker)polar front jet(subtropical jet),a weaker low-level moisture transport belt,and an active western Pacific tropical system,are more likely to induce drought in Jiangxi Province.