Evaluation and division on climatic risk of rice delayed cool damage in Jilin province

Jilin province is one of the major rice production areas in China. The rules of rice delayed cool damage and its risks were studied in order to prevent the damage and protect rice food safety. Based on the mean air temperature data at 46 weather stations from 1961 to 2008 in Jilin province, an index system was built, including heat variable coefficient during growing period, cool disaster frequency and its risk index as well as its climatic risk probability, and the risk of low temperature cool damage was assessed. Four indices were standardized using an extreme difference value method, and the synthetic index of climatic risk of rice low temperature cool damage was obtained by an equal weight method. The study areas were divided into five climatic risk areas of rice low temperature cool damage, i.e. the highest area, the high area, the middle area, the low area and the lowest area. The results indicate that the higher risk area is located in the east of Jilin province such as Yanbian, Baishan, and the lower one is in the most west of Jilin province, most Siping area and the south of Tonghua.