基于Copula函数的江苏省干旱频率特征分析OA

To comprehensively characterize the multivariate distribution of drought events in Jiangsu Province,this study employed the run theory and the standardized precipitation index to extract drought events from 1961 to 2023 across 67 meteorological stations.The spatiotemporal variations of drought characteristics were investigated,and the optimal Copula functions were selected to construct bivariate joint distributions for drought variables.Three joint return periods under two conditions were calculated.Results indicate that drought events occurred more frequently in most areas of Huaibei,eastern Jianghuai,and parts of southern Jiangsu along the Yangtze River,while fewer events were observed in western Jianghuai and southwestern Jiangsu.The spatial distributions of mean drought severity and duration exhibit similar patterns,with synchronized extreme values appearing during decreasing trends.Statistical analysis revealed that drought duration and severity are significantly correlated at all stations,both following the generalized extreme value distribution.The optimal joint distributions are predominantly characterized by Gumbel-Copula and Frank-Copula functions.Although spatial differences exist in joint return periods under two severity levels,the eastern Huaibei,Jianghuai,and southwestern Jiangsu regions consistently show lower return periods.This suggests that despite fewer drought events,these areas face higher risks of high-severity droughts,necessitating enhanced monitoring and preparedness.