The South China encounters rainwater "wheel battle" The Yangtze River Basin welcomes the "adult ceremony" test

The South China encounters rainwater "wheel battle" The Yangtze River Valley welcomes the "adult ceremony" test

From the end of March, the “recycling” mode of rainwater was started in Jiangnan and South China. Fang Qi, forecaster of the Central Meteorological Observatory, said that heavy rainfall continued to occur in the southern region, mainly due to the strong intensity of the subtropical high in the early period. South China and Jiangnan were just in the north of the subtropical high-pressure belt. The southerly warm and humid airflow was strong and had good water vapor conditions. Coupled with the cold air in the north, the south and south of the Yangtze River have formed a relatively clear exchange of warm and cold, which brings rounds of heavy precipitation to these areas.

According to experts, under normal circumstances, the "air force" of cold air will advance from north to south, from west to east, and eventually enter the sea. Therefore, the recent rainfall in the south often begins in the Jianghuai and northern Jiangnan, and then ends in the south of the Yangtze River and ends in southern China. After that, the warm and humid air will quickly “occupy” the south. When a new round of cold air arrives, it will begin to reproduce the previous rainfall process.

Is the rain cycle non-stop, is it related to the El Niño event? Zhou Bing, an engineer and expert at the Climate Monitoring Office of the National Climate Center, believes that under the influence of El Niño, many circulation systems may be abnormal. When El Niño changes the regional circulation, the subtropical high that affects China may be stabilized in a certain area and no longer travels north and south. The rain belt will also be relatively stable, resulting in concentrated and continuous precipitation in some areas and reduced precipitation in other areas.

Does the current precipitation “reproduce” the 1998 flood pattern?

Similar backgrounds in the super-strong El Niño event, similar to the rare winter scorpion and early squatting, have raised concerns about whether this year will “reproduce” the 1998 flood pattern. According to expert analysis, the current rainfall situation has the same points as in 1998, and there are also differences.

The same is true, in the background of the super El Niño, the precipitation after the fall is more. Since October last year, there have been 10 heavy rains in the south of China, which is an average of 1 times more than that in the same period since 2000. The precipitation is 50% more than normal in the same period of the previous year.

The difference is that from late March to late April 1998, the rainstorm process was only two times, which was significantly less than that of the same period of this year. The data show that the 1998 heavy rainfall process began mainly from the middle and late June, followed by continuous heavy rain in the middle and lower reaches of the Yangtze River, and then the rain belt moved westward to the upper reaches of the Yangtze River such as Sichuan and Chongqing. In the second half of July, it moved eastward again to the middle and lower reaches, and in August it returned to Sichuan, Chongqing and Hanjiang river basins. In the flood season, the whole rain belt is around the Yangtze River, which makes the Yangtze River flood form a “peak peak” and the flood control situation is extremely tense.

Although China has not yet entered the main flood season, it is necessary to pay close attention to the “superimposed effect” of continuous rainfall in the south. Fang Wei said that since the beginning of March 21st in southern China, most of the heavy precipitation occurred in the south-central part of the south of the Yangtze River and the northern part of southern China. The soil is relatively saturated, the water level of rivers and lakes is high, and the precipitation in the later period will be concentrated in these areas, which needs to be highly vigilant.

Can the Yangtze River Basin be tested by the "Adult Ceremony" after 18 years?

From 1998 to 2016, two super El Niño events were separated by 18 years. After 18 years, can the Yangtze River Basin withstand the test of "adult ceremony"?

The flood control dam is the “Great Wall of Water” that ensures the peace of the river. It is understood that the current dry levees in the middle and lower reaches of the Yangtze River have reached the standard of actual flood control in 1954. Some tributaries, Dongting Lake and the key levees in the Poyang Lake area have been heightened and reinforced, forming a 34,000-km dike system, and the flood control capacity has been greatly improved. .

At the same time, with the large-scale hub projects and reservoirs put into use one after another, to ensure the stability of the Yangtze River, there is also a "safety valve." Chen Guiya, deputy director of the Water Resources Protection Office of the Water Resources Commission, told the reporter that the number of reservoirs currently integrated into the reservoir group of the upper reaches of the Yangtze River has reached 21, and the flood control capacity is 36 billion cubic meters. In recent years, the joint dispatching practice of the controlled reservoirs of the dry tributaries has been successfully implemented. The scheduling capability has been greatly improved.

In the face of an extremely severe flood season, the National Defense General stressed that it is necessary to further enhance the sense of responsibility and urgency, conscientiously implement the flood control and drought relief executive head responsibility system, and ensure that measures such as flood control and drought relief projects, teams, and materials are in place.