Risk Assessment Of Typhoon Disaster And Research On Decision-making Technology Of Disaster Mitigation

As global warming and socio-economic development continue to accelerate,the frequency and extent of extreme weather hazards are increasing.The regional distribution of disasters in China is becoming more and more obvious due to the changing climatic and topographical factors.Coastal areas are extremely vulnerable to extreme weather disasters such as typhoons due to their proximity to the sea and their special geographical location.Typhoons and their accompanying disasters such as heavy rainfall,flooding and storm surges cause huge losses to cities along the sea and seriously threaten the lives and property of people along the coastline.Typhoon risk assessment and disaster prevention and mitigation risk management in coastal areas are crucial to maintaining the socio-economic development of cities along the coast.Based on the disaster-causing characteristics of typhoon hazards,this paper conducts a risk assessment of typhoon hazards in Hainan Island,constructs a comprehensive risk assessment system for typhoon hazards that includes the hazards of disaster-causing factors and the vulnerability of disaster-bearing bodies,and classifies the risk areas of typhoon hazards in each county and city of Hainan Island based on the assessment results.Based on system dynamics,a system dynamics model for typhoon disaster prevention and mitigation is established to predict and simulate the implementation of disaster prevention and mitigation measures,providing theoretical basis and technical support for government departments to formulate disaster prevention and mitigation plans.The main research content of this paper is as follows.(1)A comprehensive risk assessment technology system for typhoon hazards has been constructed.By analysing the existing data on typhoon disasters,including the disaster-causing laws,disaster-causing intensity and disaster prevention and mitigation measures,it is concluded that typhoon disasters are mainly caused by high winds and heavy rainfall,etc.On this basis,a comprehensive risk assessment model for typhoon disasters is proposed.The risk of typhoons in Hainan Island is calculated according to the risk evaluation model.The risk of typhoons in each county unit is analysed comprehensively,and the disaster risk areas in Hainan Island are divided by the size of the risk values.The assessment results show that Haikou City in Hainan Province is a high-risk area with a large population and a high degree of typhoon hazard causation.Wenchang,Dongfang and Sanya are medium-risk areas,belonging to the eastern and south-western coastal cities.Of the remaining counties and cities,13 are low to medium risk areas,with a distribution from coastal to inner cities.Baisha Li autonomous county is a lowrisk area,belonging to the central and western cities.The overall distribution of risk values gradually decreases along the east-west coastal areas towards the central cities.(2)Taking Haikou city,a high-risk area,as the main research area,the model construction and simulation of disaster prevention and mitigation is based on system dynamics.The variables and weighting indexes required for the model were constructed,and three sub-blocks of the model,namely material and personnel dispatch,disaster information dissemination and disaster system,were established to simulate the risk of damage to four types of disaster-bearing bodies,namely the city's power system,buildings,reservoirs and dams,and road traffic,as a result of the typhoon disaster.It also analyses the degree of influence of the government's emergency resource dispatching capacity,disaster warning level,vulnerability of disaster-bearing bodies,and emergency personnel deployment scenarios on the reserve of disaster prevention resources,the heat of information dissemination,and the rate of disaster risk reduction,and conducts a simulation prediction assessment of the implementation of the model's disaster prevention and mitigation measures.The simulation results show that: the higher the government's resource dispatching capacity,the faster the city's emergency response capacity reaches its peak rate;the information heat rises rapidly to its peak and then decreases slowly,depending on the warning level and emergency response capacity;disaster-resistant reinforcement of buildings and power systems,reducing their vulnerability,and increasing the ratio of disaster prevention and mitigation staff in reservoirs and dams and transportation can largely mitigate the disaster situation.The model can provide technical support for the government to formulate disaster prevention and mitigation strategies.