基于Copula函数的江淮流域梅雨期台风降水量与梅雨雨强遭遇概率分析

Encounter Probability Analysis of Typhoon Precipitation and Meiyu Rain Intensity in the Yangtze-Huaihe River Basin Based on Copula Function

在气候变化和城市化背景下,江淮流域台风与梅雨遭遇时的降水概率特征尚不明晰。为此,基于1961~2020年江淮流域及其子区域梅雨期台风降水量与梅雨雨强,使用Copula函数建立并求解台风与梅雨遭遇概率模型,分析了梅雨期台风降水量与梅雨雨强的联合概率分布、联合重现期和50年联合重现期对应的降水量。结果表明,江淮流域台风与梅雨遭遇时低台风降水量、高梅雨雨强事件发生的概率较大,高台风降水量、低梅雨雨强和高台风降水量、高梅雨雨强事件发生的概率较小,梅雨期台风降水量与梅雨雨强的联合重现期大多不超过5年,梅雨期台风降水量与梅雨雨强双变量50年联合重现期对应的降水量比单变量50年重现期对应的降水量大,说明台风与梅雨遭遇概率分析能反映出两者同时发生时较强的致灾能力,可为江淮流域暴雨洪涝灾害事件预警和水资源调度提供参考。

Under the background of climate change and urbanization,the precipitation probability characteristics are still unclear when typhoon and Meiyu encounter over the Yangtze-Huaihe River Basin.Based on the typhoon precipitation and Meiyu rain intensity during the Meiyu period over the Yangtze-Huaihe River Basin and its subregions from 1961 to 2020,an encounter probability model of typhoon and Meiyu was established by using the Copula function,and the joint probability distributions,the joint return period and the precipitation of 50 years return period were analyzed.The results show that the probability of low typhoon precipitation and high Meiyu rain intensity is larger,high typhoon precipitation and low Meiyu rain intensity,high typhoon precipitation and high Meiyu rain intensity are smaller.Most of the joint re-turn period of typhoon precipitation and Meiyu rain intensity are not exceed 5 years.The rainfall corresponding to the 50-year joint recurrence period of the double variables of typhoon precipitation and rainfall intensity of Meiyu period is larger than that corresponding to the univariate 50-year recurrence period,which indicates that the encounter probability model of typhoon and Meiyu rain intensity can reflect the stronger disaster-causing capacity.This study can provide a reference for warning of extremes rainfall-flooding events and water resource dispatching in the Yangtze-Huaihe River Basin.