When the Qinghai-Tibet Plateau is affected by the southwest monsoon, what is the atmosphere in Central China and South China?

When the Qinghai-Tibet Plateau is affected by the southwest monsoon, it indicates that it is summer in China.

In summer, the western Pacific subtropical high (hereinafter referred to as subtropical high) is the most important weather system affecting China. The subtropical high is a closed anticyclone, and the southerly wind blows from the northwest of the cyclone, forming a warm ridge (warm because the wind blows from the south, and the south is warmer). Generally speaking, the north and south ends of the subtropical high are about 10~ 15 latitude apart, and the center of the subtropical high is dominated by dry and hot weather. Because of the southerly warm wind, the inland southerly cold air or the mid-latitude westerly wind (generally weak in the east of China, due to the role of the Qinghai-Tibet Plateau), frontal rain and precipitation are easy to form.

The place where precipitation is formed is also about 5~ 10 latitude from the subtropical high center.

In normal years:

At the end of April and the beginning of May, the ridge line of the subtropical high moved near 20 degrees north latitude. At this time, it is the Qingming Festival, that is, the pre-flood season in South China (also known as dragon boat water), and it rains in South China. At this time, the rainy season in the north, especially in the North China Plain, has not yet arrived, and the temperature has risen, resulting in "spring drought".

From the end of May to June, the northern ridge line of the subtropical high reaches about 25 degrees north latitude. At this time, there is plum rain in Central China, and the rain in South China is relatively reduced (this year is special).

In July and August, the ridge line of subtropical high jumped to about 30 degrees north latitude. At this time, the Meiyu technology in Central China ended, and it was dry and sultry, resulting in "autumn drought" (autumn tiger). There are frequent floods and heavy rains in North China in summer. South China began to be affected by tropical cyclones (typhoons) and the southwest monsoon of the Indian Ocean, and precipitation increased. (The typhoon came early this year, which is also quite special. )

However, in the year when the subtropical high moves abnormally, it is possible that due to the high speed of the subtropical high, floods and droughts may occur in some areas. For example, if the ridge of subtropical high stays near 25 north latitude for a long time, serious floods will occur in the middle and lower reaches of the Yangtze River, which is more serious than in the northeast.

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