Integrated meteorological disaster risk regionalization of rice in Sichuan Province

The trend and meteorological yields were decomposed using the High-Pass (HP) filtering method based on the data of rice yield per unit area from 1981 to 2012 in 82 counties of Sichuan Province, China. The spatial distribution characteristics of average yield loss rate, variation coefficient of yield loss rate, and risk probability of different yield loss rate in different grades were analyzed in the lean years and disaster years with the relative meteorological yield, which was calculated with the trend and meteorological yields. Integrated meteorological disaster risk zoning was carried out on the basis of the risk zoning indexes of the disaster years. The HP filter method could be applied to the separation of the meteorological yield in Sichuan Province. The meteorological yield of rice in Sichuan Province had significant quasi-4 a and 7 a periodic oscillation characteristics. The average yield loss rate showed a high-low-high distribution from southwest to northeast in the study area. More than 80% of counties displayed an average yield loss rate of 2%-7% in the lean years and 6%-15% in the disaster years. For all counties, the variation coefficient of yield loss rate was 0.6-2.2 in the lean years and 0-1.2 in the disaster years. The areas with relatively high variation coefficient of yield loss rate were located in the west of southwestern mountainous region, the southern parts of the basin and the mountainous region in the northern part of the basin. The large-value probability areas of different yield loss rates were mainly concentrated in Guangyuan City and Bazhong City, as well as in Yanting, Gulin, Yanyuan, Yuexi. The high-risk areas of rice integrated meteorological disaster were mainly distributed in the mountainous regions of the southern, northern and southwestern parts of the basin. The medium-risk areas were mainly located in the hilly region of the basin and the surrounding low mountainous region. The low-risk areas were mainly distributed in the plain and shallow hilly regions of the basin and the east-central Liangshan Prefecture. The results of risk zoning were consistent with the distribution data of the meteorological disasters and the rice agro-meteorological disasters in Sichuan Province. The data provide a scientific basis and important reference for rice disaster prevention and mitigation in Sichuan Province.