Rainfall-Related Weather Indices for Three Main Crops in China

Rainfall-relatedhazards—deficitrainand excessive rain—inevitably stress crop production,and weather index insurance is one possible financial tool to mitigate such agro-metrological losses.In this study,we investigated where two rainfall-related weather indices—anomaly-based index(AI)and humidity-based index(HI)—could be best used for three main crops(rice,wheat,and maize)in China’s main agricultural zones.A county is defined as an“insurable county”if the correlation between a weather index and yield loss was significant.Among maize-cropping counties,both weather indices identified more insurable counties for deficit rain than for excessive rain(AI:172 vs 63;HI:182 vs 68);moreover,AI identified lower basis risk for deficit rain in most agricultural zones while HI for excessive rain.For rice,the number of AIinsurable counties was higher than the number of HI-insurable counties for deficit rain(274 vs 164),but lower for excessive rain(199 vs 272);basis risks calculated by two weather indices showed obvious difference only in Zone I.Finally,more wheat-insurable counties(AI:196 vs 71;HI:73 vs 59)and smaller basis risk indicate that both weather indices performed better for excessive rain in wheatplanting counties.In addition,most insurable counties showed independent yield loss,but did not necessarily result in effective risk pooling.This study is a primary evaluation of rainfall-related weather indices for the three main crops in China,which will be significantly helpful to the agricultural insurance market and governments’policy making.