What are the characteristics of subtropical monsoon climate?

The middle and lower reaches of the Yangtze River lie in the east of the Qinghai-Tibet Plateau. In winter, the north-south jet of the westerly belt meets over this area, forming a relatively stable shear line. Coupled with the influence of Nanling Mountains, a quasi-static front of South China appeared on the ground, with frequent cyclones and extremely rainy weather. In June, 5438+February and June, 5438+1October, the average precipitation in most areas is about 40 mm~50 mm, and in February, it is 60 mm. Since March, the warm and humid air flow in the south has strengthened and the precipitation frequency has increased. In late March, Gannan first entered the spring rain period, and the spring rain gradually extended to the northwest, southwest and northeast. In most areas, the spring rain doesn't end until early and middle June. There is a lot of precipitation and a long rainy period in the hilly areas of the south of the Yangtze River. In most areas, the spring rain begins in early April and ends in late May, and the rainy season lasts for 60 days. There are more spring rains in this area, and the proportion of spring rains in Changsha and Nanchang is about 40%, which is more than summer rain. In Hangzhou, Nanjing, Shanghai, Wenzhou and other places, spring rain accounts for about 25% of the annual precipitation. This seasonal distribution of precipitation is closely related to the geographical location of the middle and lower reaches of the Yangtze River and the atmospheric circulation process.

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