STUDY ON THE DISTRIBUTION OF EXTREMEPRECIPITATION AND ITS POTENTIAL RISKS IN THEMIDDLE AND LOWER REACHES OFTHE YANGTZE RIVER IN CHINA

摘要

As global warming continues to intensify, ex- treme weather occurs from time to time, and extreme precipitation is the main cause of floods. For the middle and lower reaches of the Yangtze River in China, the analysis of extreme precipitation patterns is crucial to the prevention of flood risks. Regarding the extreme precipitation problem in the middle and lower reaches of the Yangtze River, in this paper, we have systematically analyzed the six indexes of ex- treme precipitation analysis in the middle and lowerreaches of the Yangtze River. Furthermore, two rela- tive precipitation indicators were proposed, namelytotal extreme precipitation (R99P) and total abnor- mal precipitation (R95P). According to the law of precipitation changes in the middle and lower reaches of the Yangtze River from 1960 to 2019, it is concluded that the highest value of the average an-nual precipitation is 1 348.92 mm from 1980 to 1989 On the whole, the average annual precipitation in the middle and lower reaches of the Yangtze River has a tendency to gradually decrease. The precipitation inthe middle and lower reaches of the Yangtze River is mainly concentrated in spring and summer. In the past 60 years, the precipitation intensity, maximum precipitation, number of consecutive days without precipitation, total extreme precipitation, and total abnormal precipitation in this area have all shown a gradual upward trend. This shows that extreme weather with rainfall in the middle and lower reachesof the Yangtze River is gradually increasing, and the risk of flooding will continue to increase.