关键词: 冬小麦, 防范分区, 连阴雨, 灾害风险, 主导因子

Abstract: Continuous rain is an extreme weather event relevant to climate change that has caused difficulties in the harvesting, drying, storage, and transportation of winter wheat. These issues generally degrade wheat quality, resulting in high yield but poor crop income. Based on daily precipitation observation data from 839 national meteorological stations in China and crop phenology data from 778 Chinese agrometeorological stations, the frequency, longest duration and maximum total precipitation during the harvesting period of winter wheat were extracted and calculated for 265 stations in winter wheat region of China. By constructing a “disaster stress-exposure-adaptation” risk evaluation system and using an entropy weight grey correlation model, we evaluated the continuous rain disaster risk for winter wheat in 166 cities in China. On this basis, areas with high risk of continuous rain disaster were partitioned for risk prevention according to different dominant risk factors. Results showed that: 1) Spatially, disaster stress decreased significantly from south of the Qinling-Huaihe to north in a banded pattern. Both exposure level and adaptation level of disaster showed the pattern interlaced with high and low levels. The high exposure areas were mainly concentrated in western part of North China, the western Huang-Huai region and the southeastern part of Southwest China. The high adaptability areas were concentrated in municipalities, provincial capitals and their neighboring cities. 2) The disaster risk level for continuous rain on winter wheat was determined on the basis of three factors: disaster stress, exposure and adaptability. The regions with the highest and higher risk levels were mainly concentrated in the western Huang-Huai region, the western Yangtze-Huaihe region, the southeastern part of Southwest China and Southwest China, while the lowest and low risk levels were mainly concentrated in municipalities, provincial capitals and their surrounding cities. The number of cities above the medium level of risk accounted for 73% of all cities, directly threatening the harvest of 22.262 3 million hectares of winter wheat. 3) Disaster stress and disaster adaptation factors were each divided into two grades, high and low, according to natural breaks method, and the two factors were combined to partition the prevention areas of winter wheat. Areas of high stress and high adaptability were named stress-dominated areas, areas of low stress and low adaptability were named adaptation-dominated areas, areas of high stress and low adaptability were named stress-adaptation-dominated areas, and areas of low stress and high adaptability were named exposure areas. The hotspots of disaster risk were mainly stress-adaptation-dominated areas and adaptation-dominated areas. Strengthening disaster monitoring and early warning and improving regional adaptability can serve as effective ways for reducing the risk of continuous rain disaster.

Key words: continuous rain, disaster risk, dominant factor, prevention partition, winter wheat