Henan suffered heavy rain in many places, and Zhengzhou suffered the strongest rainfall on record. After the disaster, all localities quickly organized rescue and disaster relief. So what is the reason for the rainstorm in Henan? Today, I sorted out the causes of Rainstorm in Henan for your reference. Let's have a look!
Causes of Rainstorm in Henan
On the 21st, the Central Meteorological Observatory held a media briefing to introduce the rainstorm in Henan. According to reports, four major reasons led to the rare rainstorm in Henan.
First, the situation of atmospheric circulation is stable. The Western Pacific subtropical high and the continental high are stably maintained in the sea of Japan and Northwest China respectively, resulting in the stagnation and little movement of the low value weather system between them in the Huang Huai Region, resulting in the precipitation weather in central and Western Henan for a long time.
Second, abundant water vapor conditions. In mid July, Henan was on the edge of the subtropical high, with convective instability and sufficient energy. On the 18th, a typhoon "fireworks" was generated in the Western Pacific and approached China. Guided by the easterly airflow on the periphery of the typhoon and the south side of the subtropical high, a large amount of water vapor is transported to China's inland areas, which provides an abundant water vapor source for heavy rainfall in Henan and has high precipitation efficiency.
Third, the topographic precipitation effect is significant. Affected by the deep easterly jet and low vortex shear weather system, and the special terrain of Taihang Mountain and Funiu Mountain in Henan Province has a lifting and convergence effect on the easterly air flow, the heavy precipitation area is stable and less moving in the mountainous areas in the West and northwest of Henan Province, and the precipitation increase in front of the windward slope is obvious.
Fourth, the convective "train effect" is obvious. Under the stable weather situation, medium and small-scale convection repeatedly develops in the front of Funiu Mountain and moves towards Zhengzhou, forming a "train effect", resulting in high precipitation intensity and long maintenance time, resulting in strong precipitation at the local polar end.
How big is the rainstorm in Henan
Since the night of July 17, there have been torrential rain, heavy rain and local torrential rain in Henan Province. Heavy rainfall is mainly concentrated in the western, northern and central regions. Severe rainstorms occurred in Zhengzhou, Jiaozuo, Xinxiang, Luoyang, Nanyang, Pingdingshan, Jiyuan, Anyang, Hebi and Xuchang.
The monitoring showed that from 17:00 on the 19th to 17:00 on the 20th, heavy rain occurred in most parts of the province, and heavy rain occurred in Zhengzhou, Xuchang, Xinxiang and other areas. The average rainfall of the whole province is 73.1mm. The average rainfall of Zhengzhou, Xuchang and Xinxiang are 286.5mm, 141.5mm and 129.6mm respectively. There are 2587 rainfall stations with precipitation of more than 50mm, 1198 more than 100mm and 311 more than 250mm. The maximum precipitation occurred in Jiangang, Zhengzhou City, 584.0 mm.
Zhang Juan, a Chinese weather and meteorological analyst, said that from 8:00 on the 19th to 8:00 on the 20th, such as 364.6mm in Songshan and 254.9mm in Xinmi, were the first severe rainstorms in the region, and several stations broke the single day precipitation record in July. Take Songshan for example. The accumulated rainfall here is large, persistent and strong. From 18 to 16:00 on the 20th, the accumulated rainfall in Songshan and Xinmi has reached 557mm and 512.7mm. There was a 166mm rainstorm in Zhengzhou on the 19th, which is the strongest single day rainfall since the flood season. However, the heavy rainfall in Zhengzhou on the 20th continues, with a single hour rainfall of 201.9mm from 16 to 17:00. Obvious waterlogging and ponding have occurred in Zhengzhou and Songshan.
What are the characteristics of this precipitation process
First, it lasts for a long time. Since July 17, the western and central and western regions of Henan Province have experienced large-scale heavy precipitation for four consecutive days, and the heavy precipitation will continue.
Second, the accumulated rainfall is large. The average rainfall of the whole province is 113.5mm. The average rainfall of Zhengzhou, Jiaozuo and Xinxiang are 357mm, 210.6mm and 194.5mm respectively. The maximum precipitation occurred at 728.0 mm in huancuiyu, Xingyang city.
Third, there is a wide range of heavy precipitation. There are 4098 rainfall stations in the province, with precipitation of more than 50mm, 1923 more than 100mm and 606 more than 250mm.
Fourth, the heavy precipitation is concentrated during the period. The heavy rainfall period mainly starts from the night of the 18th. There are general rainstorms, heavy rainstorms and local heavy rainstorms in the north, central and western regions.
Fifth, it is extreme. Songshan, Yanshi, Xinmi, Yichuan, Dengfeng and other five stations have broken through the historical extreme value of daily precipitation since the establishment of the station. Songshan, Gongyi, Xinmi, Yanshi, Dengfeng and other five stations have broken through the historical extreme value of 3-day cumulative precipitation since the establishment of the station.
What to do in case of flood
1. Sufficient time and quick transfer: if there is enough time under the threat of flood, it shall be transferred to hillsides, highlands and other places in an organized manner according to the predetermined route.
2. Go up high and catch floating objects: when the flood comes too fast to transfer, you should immediately climb the roof, big trees and high walls, temporarily avoid danger and wait for rescue. You can also grasp buoyant objects such as wooden pots, wooden chairs and wooden boards. Remember not to avoid danger on Adobe houses, which are easy to collapse after being immersed in water.
3. Raft making and dangerous place: if the water condition is serious, consider making a raft with bed board, door board, box, etc., or use the inner tube of automobile tire to make a simple life buoy to get out of the dangerous place as soon as possible.
4. Send signals for rescue: protect communication equipment during escape, prepare flashlights, brightly colored flags or bed sheets, and send rescue signals in time when conditions permit.
5. Escape first, don't love money: don't haggle over your family's property, let alone delay the best escape time by focusing on your family's property.
6. Call for help slowly and save physical strength: in case of flood, when the building is buried, try to save energy, and call for help when it is determined that there is someone in the annex, so as to prolong the survival time as far as possible and wait for rescue.