Design of Weather Index Insurance Contact for Tea Frost
摘要
This paper takes tea production in Xinchang County of Zhejiang as an example,under the principle of disaster risk analysis and requirement for agricultural insurance,combined with characteristics such as huge topographic relief and significant difference in microclimate in southern mountain area of China,carries out risk evaluation and agricultural insurance product design through elaborating frost disaster which affected tea production in March at village township level.Firstly,the paper confirms tea's economic output changes from time to time in productive life based on tea's daily economic output in normal years of tea planting base;combined with economic loss rate due to frost during/before productive life in previous years to confirm frost weather index—minimum temperature in a period before productive life or after productive life,different minimum temperature is in accordance with tea's economic loss rate.Support Vector Machine(SVM) is used to extend mesoscale automatic weather station's minimum temperature data to 30 years in specific to non-linear relation existing among meteorological data of mesoscale automatic weather station in villages,towns and county;minimum temperature corresponds to tea's economic loss rate,therefore it's possible to calculate different levels of frost risk based on minimum temperature data and confirm tea's economic loss risk,and to solve problems such as tea's short planting period,short accumulation period for mesoscale automatic weather stations and unable to meet risk analysis requirement.There're certain differences between risk results calculated on different risk analysis models.The article applies probability density function fitting distributions such as Beta,Exponential,Gumbel,Gamma,Generalized Extreme Value,Inverse Gaussian,Logistic,Log-Logistic,Lognormal,Lognormal2,Normal,Pareto,Pareto2,Pearson Type V,Pearson Type VI,Student,Weibull to minimum temperature data sequence in every township and street in the study area.Par