The ＂culprit＂ of the rainstorm in the north turned out to be it!
The heavy rain in the south must have caused the people in the south a deep pain. Now, God has finally "stained the rain and dew", and the north has also begun to "rattle". Unexpectedly, the rainfall in the north turned out to be "wow", and some of it was too much, which brought trouble and even disaster to many places. So, how strong is the rainstorm in the north, and who is the "behind-the-scenes director" of the rainstorm?
How violent is the rainstorm in the north?
How heavy is the rain in the north this time? Let’s look at a picture of precipitation in the Central Meteorological Observatory first.
On the 19th, large-scale heavy rainfall occurred in North China, Huanghuai and other places, with rainfall exceeding 200mm in three hours in some areas. Together with Jianghan area, the rainstorm area of 50 mm or more reached 635,000 square kilometers, including 250 mm or more in southern Hebei, northern Henan, central and western Hubei, and the daily rainfall in 17 counties and cities in Shanxi, Hebei and Hubei exceeded historical extremes.
Affected by the rainstorm, serious waterlogging occurred in Taiyuan, Shanxi, Handan and Xingtai, Hebei, and flash floods occurred in some areas.
Taking Hebei and Henan as examples, the Meteorological Bureau of Hebei Province issued a red rainstorm warning on the 19th. From 8: 00 on the 18th to 18: 00 on the 19th, the total precipitation in Taoquan Township, Handan County of the province exceeded 500mm, and the torrential rain caused flash floods in the local area.
From 20: 00 on the 18th to 17: 30 on the 19th in Linzhou City, Henan Province, the rainfall in East Ma ‘an of Linzhou City was 679.5mm, while the average annual rainfall in northern Henan Province was only about 600mm, which means that it rained for one year in less than one day!
In addition, heavy rainfall in the north will continue. According to the forecast of the Central Meteorological Observatory, there will be heavy rains in North China, the eastern and southern parts of Huanghuai and the southern part of Northeast China from the 20th to the 21st. In some areas, there will be heavy rains with a cumulative rainfall of 50-80mm, 90-150mm in some areas and over 200mm in some areas. The Central Meteorological Observatory continued to issue an orange rainstorm warning on the morning of the 20th.
Who is the "initiator" of this heavy rainfall?
The answer is: Huanghuai cyclone!
What is this? Don’t worry, before explaining it, let’s learn what a cyclone is.
First of all, a cyclone is a kind of weather system. Frankly speaking, it is a low-pressure system, which is a horizontal vortex with a lower central pressure than its surroundings. Its horizontal scale is between two or three hundred kilometers and two or three thousand kilometers. Because the airflow meets in the center of the cyclone from all directions, it will inevitably produce upward movement, and the airflow will rise to the upper air and flow out around, so as to ensure that the lower atmosphere will continue to flow in from the periphery to the center, and the cyclone can exist and develop. Because there is a vertical updraft in the center of the cyclone, when the cyclone transits, the cloud cover in the center area increases, and rainy weather is common.
Cyclones can be divided into temperate cyclones, tropical cyclones and polar cyclones according to the latitude zone of generation and activity. You may be familiar with tropical cyclones. The typhoon that affects the southeast coastal areas of China in summer and autumn is a strong tropical cyclone. Many people may rarely hear about extratropical cyclones, but in fact, China is affected by extratropical cyclones all year round, which often leads to rainy weather, sometimes accompanied by heavy rain or strong convective weather. It is also often the key disaster-causing system for the occurrence of regional abnormal floods in China.
Huanghuai cyclone, the "culprit" of this rainstorm, is a kind of temperate cyclone. In China, the names of extratropical cyclones are different according to different geographical and climatic characteristics, such as Mongolian cyclone, Jianghuai cyclone, East China Sea cyclone and Taiwan Province cyclone.
So how did the Huanghuai cyclone, which was "raining" in the north, form? In fact, extratropical cyclones are generally the product of large-scale collision between cold and warm air. Specific to this process, it is because the subtropical high pressure strengthens the northward movement, and there is a strong warm and humid airflow outside it, which transports a steady stream of water vapor. These water vapors meet with cold air violently in North China and Huanghuai area, forming a strong Huanghuai cyclone. The general situation is stable and the water vapor is sufficient, which leads to the occurrence of heavy precipitation weather.
Bonus skills: What should we do when the rainstorm comes?
First, try not to go out during the rainstorm, and pay attention to the weather forecast through radio, television, mobile phone or internet in time to grasp the latest news of the rainstorm.
Second, check the circuit, fire and other facilities. When the accumulated water is immersed in the room, cut off the power immediately to prevent the accumulated water from being charged and hurting people.
Third, cover the drying items in advance, and pack up valuables at home and put them in a high place.
Fourth, residents should adjust measures to local conditions, and put water baffles, sandbags or mounds at home.
Fifth, when driving on the road or under the overpass, try to bypass; The car stalled in the low-lying water, and got off to a high place to wait for rescue.
Sixth, mountain residents should pay attention to prevent mountain torrents. When the upstream water suddenly becomes turbid and the water level rises rapidly, they need to move to a safe area in time. When the mountain torrents and debris flows hit, they immediately ran to the heights on both sides of the gully bank perpendicular to the mountain torrents and debris flows.
The article was produced by China, a popular science student, and was authorized to be published in the column "Learning Science with Xiaobian" of CCTV. Please indicate the source for reprinting.
Production: Weather intelligence agency
Producer: computer network information center