东亚夏季风指数分类与长江中游地区夏季降水的关系

选取适当的亚洲夏季风指数并对它们进行分类，结合1979-2020年长江中游地区夏季降水资料，分析了夏季风异常年份长江中游地区夏季大气环流和降水的特征。主要得出以下结论：（1）两类夏季风指数都与长江中游地区夏季降水呈负相关关系，并且第二类夏季风指数与长江中游地区夏季降水的相关关系更加显著，因此选取第二类夏季风指数来反映长江中游地区夏季降水特征。（2）长江中游地区的降水具有低频振荡特征，在第二类夏季风指数高值年和低值年，振荡的主周期都是32-64天。（3）第二类夏季风指数高值年和低值年的降水差异主要取决于西太平副高的强度和偏南季风的水汽输送。

Relationship between East Asian Summer Monsoon Classification and Summer Precipitation in Middle Reaches of The Yangtze River

Selecting appropriate Asian summer monsoon indices and classifying them, combined with the summer precipitation data in the middle reaches of the Yangtze River from 1979 to 2020, analyzed the characteristics of summer atmospheric circulation and precipitation in the middle reaches of the Yangtze River during the abnormal summer monsoon years. The main conclusions are as follows: (1) Both types of summer monsoon indexes are negatively correlated with summer precipitation in the middle reaches of the Yangtze River, and the correlation between the second type of summer monsoon indexes and summer rainfall in the middle reaches of the Yangtze River is more significant, so the second type is selected The summer monsoon index determines the strong and weak summer monsoon years. (2) The precipitation in the middle reaches of the Yangtze River has the characteristics of low-frequency oscillation. In the strong summer monsoon year and the weak summer monsoon year, the main period of the oscillation is 32-64 days. (3) The precipitation difference between strong and weak summer monsoon years mainly depends on the strength of the West Pacific Subtropical High and the water vapor transport of the southerly monsoon.