Study On The Uncertain Mathematical Model Of Return Period Of Typhoon Extreme Disaster Landing In South China

As one of the most destructive natural disasters in China,typhoon landing often causes casualties,building collapse,traffic obstacles and economic losses.Especially,the occurrence of typhoon extreme disaster(strong typhoon and super typhoon disaster)has a great impact on people's life and production in this area.South China(Guangdong,Guangxi and Hainan)has become the most seriously affected area by typhoon disaster because of its unique geographical location and climate.Therefore,it is of great significance to study the extreme disasters of typhoons in South China.This paper studies the recurrence period of the extreme disasters of typhoons landing in South China,builds the uncertain mathematical model of the extreme disasters of typhoons,and analyzes the frequency of the extreme disasters of typhoons by discussing the correlation among the disaster source.Therefore,we have done the following three aspects of research:(1)Based on the method of descriptive statistics and the theory of Copula function,the data of typhoon disasters in 1981-2014 landing in South China were studied,the optimal distribution of each factor is studied,and the correlation analysis of each factor is made.Finally,the correlation test is made between the disaster causing factor,the bearing body factor and the disaster situation factor,and the factors that have significant influence on the typhoon disaster situation are selected.(2)Taking the selected disaster causing factors as research variables,the Frank copula function is constructed to calculate the disaster causing return period.The calculation results show that the longer the disaster causing return period becomes,the more serious the corresponding typhoon extreme disaster is.Finally,according to the actual data of typhoon disasters from 2015 to 2017,the return period is calculated,and the results are compared with the disaster causing return period.(3)In order to better study the frequency of typhoon extreme disasters in South China,considering the strong correlation between typhoon disaster factors,we take the number of people affected,the area affected by crops and the direct economic loss as research variables to build Clayton Copula function model is used to calculate the return period of disaster and evaluate the disaster of typhoon extreme disaster.The results show that the longer the return period of typhoon extreme disaster becomes,the more serious the impact of disaster will become.Finally,the return period of disaster is compared with the return period of disaster.