Summer situation in subtropical high region

In different parts of subtropical high, it often causes long-term high temperature and drought in this area, but when conditions are suitable, local geothermal thunderstorms sometimes occur; On the south side of the western Pacific high, typhoons are frequent. In its easterly airflow, easterly waves often form and move westward, affecting the areas east of Yunnan and Guizhou and south of the Yangtze River, causing thunderstorms and heavy rains. On the north and northwest side of the subtropical high, a large amount of water vapor is brought from the sea because of the southerly airflow in the west. When encountering weather systems such as westerly trough or vortex, a wide range of rain belts will be produced. According to statistics, this rain belt is in the area of 5-8 latitudes north of the western ridge line of the western Pacific high, and it is generally east-west. The rainy season in South China, Jianghuai and North China are all closely related to the northward movement of the western Pacific high. The length of time that this rain belt stays in a certain area is directly related to the drought and flood in this area. Generally speaking, the longer the rain belt stops, the more floods occur, and the shorter the stay time, the more prone to drought.