Analysis of Compound Flood Event Encounters in the Pearl River Estuary under Changing Environments
Under the influence of continuous global warming,compound flood events triggered by upstream floods,tropical cy-clones,astronomical tides,and other sea and land elements driven jointly are frequent in coastal cities,seriously threatening the safety of people's lives and properties in the region.Based on 135 typhoons affecting the Pearl River Estuary during 1986-2018 as statistical samples,this study used Mann-Kendall test and Pettitt test to analyze the occurrence trend and change of composite flood events.Vine Copula was used to fit the joint distribution function of the three variables of tide level,wind speed and dis-charge of a composite flood event,and Copula likelihood ratio test was used to test the correlation structure of the joint distribu-tion function.Considering the mutation of Vine Copula function,the correlation between the three variables was enhanced,which can better reflect the dependence of each variable with the change of events,and improve the accuracy of the assessment of the recurrence period of complex flood events.In the past 30 years,the number of tropical cyclones has shown a decreasing trend,while the wind speed has shown a significantly increasing trend,and the wind speed has a sudden change in 2002,that is the characteristics of tropical cyclone events have shown a decrease in the number of occurrence and an increase in the grade.Under the changing environment,the calculated results of the combined recurrence period of extreme composite flood events such as"Hato"and"Mangosteen"are smaller than the calculated results of the traditional fixed parameter Copula recurrence period,that is the occurrence probability of extreme composite flood events in the future is increasing.
Pearl River Estuarytropical cycloneMann-KendallPettit testVine Copula FunctionCopula based Likelihood-Ratio test
万方数据
维普
