What month is the spring drought in North China? What rains in South China in July and August? What is the reason?

The spring drought in North China refers to the drought from March to May (June to August in summer and September-165438+1October in autumn). The temperature in North China rises rapidly in spring, and the precipitation in North China is less because the precipitation in North China mainly depends on the water vapor brought by the east monsoon from the Pacific Ocean, but the east monsoon mainly affects South China in spring, and the east monsoon has not affected North China yet, so the precipitation in North China is less, and the evaporation is greater than the precipitation. Moreover, the industrial development in North China, especially the heavy industry, needs a lot of water, and the natural water consumption is also very large. North China has a large population, and there is a lot of domestic water and agricultural water. These three water users add up, North China.

Intermittent rain in Mao Mao (middle and lower reaches of the Yangtze River)

In the eastern part of China, during the flood season from mid-May to early June, the main rain belt swings in Nanling Mountains and its south area. In recent years, although it moved to the north of Nanling within a certain period of time, it often stayed in the south of 28N and 29° n from a waiting period (5 days) or the multi-year average of 10 days. This period is called "rainy season in the south of the Yangtze River" or "pre-flood season in South China".

In the middle and late June, the main rain belt moved northward within the range of 29° n-33° n (that is, from Yichang in the west, to the Yangtze River estuary in the east, and then across the sea to Japan; From the south of China Lake Basin to the south bank of Huaihe River), it is stable and less active. At this time, the area south of Nanling is outside the rain belt, and the rainy weather is over; The middle and lower reaches of the Yangtze River bid farewell to the sunny early summer and ushered in the rainy season. Heavy rain and rainstorm appeared from time to time and lasted until the beginning of July. This is a famous rainy season in the middle and lower reaches of the Yangtze River.

From mid-July, the rain belt moved northward again, reaching the area north of 33 N. Stagnation and wandering in the Yellow River, Huaihe River Basin, North China, Northeast China and other places have caused heavy rainfall again and again, which are called "Huanghuai rainy season" and "North China rainy season" respectively. At this time, the plum rains in the middle and lower reaches of the Yangtze River ended, the sun hung high and entered the hot summer season. This kind of weather will last until the end of August, and then the rain belt will quickly withdraw southward with the gradual activity of cold air. In less than a month, the rain belt will always retreat to the coastal areas of South China. The regular change of this rain belt shows that the plum rain in the middle and lower reaches of the Yangtze River is not an isolated and local weather and climate phenomenon, but an integral part of the main rainy season activities in eastern China, which reflects the stagnation of the main rain belt in the middle and lower reaches of the Yangtze River.