上海市台风降雨和潮位遭遇组合概率研究

Joint Probability Investigation of Encounter Typhoon Rainfall and Tide Level in Shanghai City

针对台风期间上海市城市防洪涝安全风险问题,基于1970～2011年徐家汇气象站日降雨资料和黄浦江吴淞潮位站日潮位资料,采用P-Ⅲ型分布拟合了台风降雨和潮位的概率分布,利用Copula函数建立了上海市台风降雨与黄浦江潮位的联合分布模型,并定义和分析了台风降雨与潮位的组合风险概率及两变量重现期。结果表明,上海市台风降雨达到50mm,与年最高潮位达到警戒水位的联合重现期约为2年;10年一遇台风降雨与5年一遇或20年一遇的年高潮位的同现重现期分别为111、303年;20年一遇的台风降雨与20年一遇的年高潮位的同现重现期为625年;上海市10年一遇以上台风降雨遭遇到5年一遇以上的年高潮位的机率很小。

In order to investigate the risk probability for water logging and flood control during the influence of ty- phoons on Shanghai City, based on the historical data of Xujiahui meteorological station and the Wusong tide level station in Huangpujiang river, Pearson Type Ⅲ is used to describe the probability distribution of typhoon rainfall and tide level. And then the Copula function is applied to establish the joint distribution of typhoon rainfall and tide level. At the same time, the joint risk probability and bi-variable return period between typhoon rainfall and tide level are presented. The re- sults show that the joint return period of the typhoon rainfall reaching 50 mm and the tide level reaching warning water level is about two years in Shanghai City; the co-occurrence return period of the typhoon rainfall with a return period of ten years encountering the annual high tide level with a return period of five years or twenty years is 111 years or 303 years, respectively; the co-occurrence return period of the typhoon rainfall with a return period of twenty years encountering the annual high tide level with a return period of twenty years is 625 years; therefore, the probability that typhoon rainfall of return period more than ten years meet the annual high tide level of return period more than five years is very low.