Reasons for the formation of summer drought weather Analysis of the reasons for the formation of summer drought weather

In January and 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 subsiding airflow, with strong solar radiation, high temperature and strong evaporation. Because the air mass is single, there is no large rain area except for thunderstorms in some areas, so there is a summer drought.

2. From mid-July to mid-August. At this time, the stationary front of Meiyu has moved to the middle and lower reaches of the Yellow River and Northeast China in early July, and the middle and lower reaches of the Yangtze River are controlled by the "subtropical high", forming an anticyclone weather, which is dominated by downdraft, with long sunshine, strong solar radiation, high temperature and strong evaporation. Crops grow fast, and the water demand of farmland is great.

3. However, due to the single air mass, there is no large rain area except thunderstorms in some areas, and drought and hot summer weather generally occur, so it is called "summer drought". In this season, the afternoon temperature in the middle and lower reaches of the Yangtze River generally reaches 33 ~ 35℃, and there are high temperatures as high as 43 ~ 45℃ in some places. It mainly occurs in the Yangtze River valley in China and the south of the Yangtze River, especially in Hubei, Hunan, Jiangxi, Jiangsu, Anhui and other provinces.

4. Summer drought is characterized by strong solar radiation, high temperature, low humidity and large evaporation and transpiration, making it the hottest period of the year. Under the control of the western Pacific subtropical high, the Yangtze River Basin in China is sunny and hot with little rain, and the occurrence of summer drought is relatively frequent, up to 5%. In other areas, there are also droughts in some years.