Risk Assessment Of Typhoon Disaster For Agriculture

Typhoons are disaster weather systems that have a huge impact.On the one hand,typhoon brings massive rainwater to the mainland,alleviates the drought in some areas,and promotes agricultural production.Thus,it is of great importance for freshwater resources and ecological environment.Besides,its function of promoting thermal cycling can also maintain heat balance.On the other hand,features like sudden and strong destructive force turn typhoon into the world ’s most serious natural disaster which brings serious damage and loss to society.The risk assessment of agricultural disasters caused by typhoon is an important part of typhoon disaster research,and it is an important means to prevent the typhoon disaster and loss assessment.It is very meaningful to study the risk assessment of agricultural disasters caused by typhoon under the condition that typhoon weather data are limited space-time scale,and the statistics of agricultural disaster are not complete and the spatial information is not clear,especially in the crop affected area is not able to accurately estimate.It provides relevant reference for the healthy and stable development of agriculture.The risk assessment of agricultural disasters caused by typhoon include the risk evaluation of typhoon disaster and the estimation of agricultural disaster losses under typhoon.The risk evaluation of typhoon disaster can make the decision maker clearly aware of the crop distribution in typhoons disasters and the regional characteristics of the extent of the disaster.And the risk assessment of agricultural disasters caused by typhoon provides the basis for disaster prevention and mitigation,post-disaster reconstruction and agricultural insurance claims work.Firstly,based on analysis of the inherent mechanism of how typhoon influences crops,this paper explore the various factors which cause the disaster of the crops,and establish the risk evaluation system for typhoon disaster.By understanding ways of typhoon caused crops disaster,deducing relevant factors behind these,the paper finally digs out 11 key factors affecting the crops,including five aspects of wind,rainfall,soil,terrain,and river network.According to these factors,we established the Analytic Hierarchy Process(AHP)model,investigated and evaluated the relative importance of different disaster factors,and determined the weights of the different factors,then,risk assessment of typhoon disaster.Secondary,this paper takes Guangdong Province as an example to estimate the area of crops affected by typhoon-induced disasters.Then,we analyze the specific factors of the agriculture disaster caused by typhoon,dig out 8 related factors of typhoon-leading agriculture disaster from five aspects of wind,rainfall,soil,terrain,and river network and analyze the relationship between them.In this paper,regression equation is established by regarding these 8 factors as independent variables for judging loss of crops under rainfall and flood.Besides,we also establish judgment equation of crops damage under the condition of the wind according to researches of other scholars.By selecting typical typhoon disaster case data and using above two equations,damage area of crops is calculated by modifying parameters and iteration.Meanwhile,using the principle of least squares,we compare both estimation area and real area of typhoon caused agricultural losses,thus,model parameter was determined and estimation equation of typhoon caused agriculture loss was established as well.Finally,this study uses other typhoon disaster case data to validate the model and accuracy evaluation.In the process of estimating affected area of crops caused by the typhoon about the Kammuri(200809)、Hagupit(200814)、Goni(200907)and Kai-tak(201213)on Guangdong,the estimated error accuracy is within 20.3%.Then this paper establishs the model parameters by choosing different case data about typhoon-leading agriculture disaster,to evaluate error precisions of each model under different typhoon disaster case data and analyze influences on crops loss estimation model caused by different typhoon disaster case dataThere are three main innovations in the paper.Firstly,agricultural disaster risk assessment model about typhoon is initially established.Followed by using the relevant factors,the available method of estimating affected area of crops is preliminary given.Secondly,the rationality of the estimated area of crop affected area was verified by selecting the case date of different typhoon disaster And the results show that the method is effective in clear disaster and geographical situation,and provide a perspective of framework the subsequent precision modeling and improvement.