Risk analysis of spring low temperature and overcast rainy and its application in the rice production in Sichuan basin, China

The daily observations of 90 stations in Sichuan basin, between mid-March and early-May, were collected, and Selected the days of that daily average temperature below 12°C, the total days of that daily average temperature continuous below 12 °C for 3-days or more, effective accumulated temperature, precipitation, rainy days, the total days of that continuous precipitation for 3 days or more, sunshine duration, no sunshine days as impact factor, using Analytical Hierarchy Process (AHP) to construct risk analysis model, and finally got the spatial distribution of spring low temperature and overcast rainy in Sichuan basin, the results of research might lead to the following conclusions. The high risk region mainly in western mountain areas around the basin and the parallel Ridge Valley of the northeast basin, higher altitude and susceptible to cold air were the important reason for higher risk, while the hilly areas in the mid-basin were lower risk. And then, discussed the risk damage of rice suffered spring low temperature and overcast rainy, and proposed targeted suggests.