Causes of dry weather in summer

In early July, the middle and lower reaches of the Yangtze River were controlled by the subtropical high belt, forming an anticyclone weather, which was dominated by the underflow current, with strong solar radiation, high temperature and strong evaporation. Because the air mass is single, except for thunderstorms in some areas, there is no big rain area, so it appears early.

The influence of dry weather in summer is mainly reflected in crops, because the crops sown in spring during this period are just at the heading, flowering and filling stage, and the demand for water is relatively large.

However, due to the single air mass, except for thunderstorms in some areas, there is no big rain area, and dry, early and hot summer weather generally occurs, so it is called "Li Tang". In this season, the afternoon temperature in the middle and lower reaches of the Yangtze River generally reaches 33~35℃, and the high temperature as high as 43 ~ 45℃ appears in some places. It mainly occurs in the Yangtze River basin and the south of the Yangtze River, especially in Hubei, Hunan, Jiangxi, Jiangsu, Anhui and other provinces.

Summer drought is characterized by strong solar radiation, high temperature, low humidity and large evaporation and transpiration, which is the hottest period in a year. Under the control of the western Pacific subtropical high, the Yangtze River basin in China is sunny and hot with little rain, and early setting occurs frequently, up to 50%. In other areas, there are droughts in some years.