Why has Henan become a rainstorm center again?

Why has Henan become a rainstorm center again?

Why has Henan become a rainstorm center again? From August 2/KLOC-0 to August 24, there will be a heavy rainfall process from west to east in China, affecting 9 provinces and cities, with Sichuan and Henan having the strongest rainfall. A typical feature of this rainfall process is not only heavy rain, but also particularly strong wind.

Why has Henan become a rainstorm center again? 1 experts remind us to be alert to the superimposed influence of strong winds and heavy rains.

According to the forecast of the Central Meteorological Observatory, there will be a heavy rainfall process from west to east in China from August 2/KLOC-0 to August 24. Among them, Henan, which just experienced the "July 20" torrential rain, will encounter heavy rainfall again after a month.

What is the intensity of this heavy rainfall compared with the "July 20" rainstorm? Is the risk of disaster high? China Meteorological News reporter invited Zhang Tao, chief forecaster of the Central Meteorological Observatory, to make an authoritative interpretation.

Sichuan and Henan, which affect 9 provinces and cities, have the strongest rainfall.

Zhang Tao said that the heavy rainfall had the characteristics of wide influence range, large local rainfall and fast system movement, accompanied by strong winds in Huanghuai area. Because this process moves faster, the accumulated rainfall will not be particularly extreme, but the short-term rainfall intensity is relatively large, which needs attention; This rainfall superimposed on the disaster-stricken areas in Henan in the previous period, which had a great impact. Reservoirs, lakes and rivers need to be prepared.

Zhang Tao explained that, from the system configuration, the heavy rainfall process was typical monsoon rainfall, and the subtropical high extended westward, which made the warm and humid air flow from the Indian Ocean, the South China Sea and the western Pacific smoothly northward along the western edge of the subtropical high, and met with the cold air from the north, resulting in large-scale rainfall.

Heavy rainfall affects a wide range. Nine provinces (cities) such as Sichuan, Chongqing, Shaanxi, Shanxi, Henan, Hubei, Anhui, Shandong and Jiangsu are all in heavy rainfall areas, with moderate to heavy rain on the whole, but there will be heavy rain in several relatively concentrated places. Among them, Sichuan Basin and Henan Province have the strongest rainfall, and the local rainfall can reach 250 ~ 400 mm, which is already a rainstorm level.

Henan needs to be alert to disasters caused by superposition effect.

In this process, Henan is also the center of the rainstorm. A month later, people can't help but think of the "July 20" rainstorm in Henan last month. What are the similarities and differences between the two processes in terms of strength and causes?

Zhang Tao said that the rainstorm process in Henan was different from "July 20". This rainfall process is moving and will not reproduce the "stagnation" of previous rainfall, so the accumulated rainfall will not be particularly extreme. Furthermore, this process is a heavy rain formed by the combined action of the turning airflow and water vapor on the west side of the subtropical high, which is a typical rainstorm configuration in flood season; In contrast, in the process of "July 20", the typhoon and subtropical high were far away from the sea surface, which was an indirect influence. Coupled with the "chemical reaction" of water vapor and topography, it is unique not only in this summer, but also in history, which eventually led to this rare record-breaking rainstorm.

However, Zhang Tao particularly reminded that although the accumulated rainfall will not be particularly extreme, it may still have a very great adverse impact on Henan. Because the disaster impact caused by the extreme rainstorm in Henan a month ago has not completely passed, the rainfall area overlaps with the area affected by the previous rainstorm. It is especially recommended that the local authorities make flood control, drainage and emergency preparedness in advance.

Henan, Shandong and other places still need to guard against strong winds

Zhang Tao said that a typical feature of this rainfall process is not only heavy rain, but also extremely strong wind. With the change of summer and autumn seasons, the cold air in the north is becoming more and more active. During the collision with the warm and humid air from the south, three cyclones are generated, which fall on the line from southwest to northeast, located in the northeast, and the eastern part of the northwest reaches Henan, Shandong and Sichuan basins. These three areas are also the concentrated areas of this round of rainfall.

In particular, the cyclones from the eastern part of the northwest to Henan and Shandong brought strong winds when they moved eastward along Henan and Shandong, which increased the rain and made them more destructive. From the perspective of prevention, the area where this cyclone passes can regard this process as a "terrestrial tropical cyclone" and take precautions with high standards. According to the forecast, from 22nd to 24th, there will be 4 ~ 6 and 7 ~ 9 rotating winds in central and eastern Henan, most of Shandong and the Yellow Sea, and the local gust can reach 8 ~ 1 1.

Therefore, Henan, Shandong and other places need to strengthen outdoor billboards and temporary structures to reduce or avoid aerial work; It is necessary to guard against the adverse effects of strong winds on passing ships and offshore operations in the Yellow Sea.

The process is still uncertain, so we should pay attention to strong convective weather.

Zhang Tao proposed that at present, the approximate locations and intensities of the three rainfall centers can be predicted from the three cyclones that "rub" when cold and warm air meet. But we also need to pay attention to the much smaller strong convective weather process that may be hidden under the three rainfall centers. These strong convective processes are like "small bubbles after water boils", which are small and medium-sized systems that really determine the extreme value of single point rainfall.

From the natural law, the smaller the scale, the greater the uncertainty and the lower the predictability. Therefore, all localities need to dynamically pay attention to the short-term forecast and early warning information updated by the local meteorological department.

Why has Henan become a rainstorm center again? From August 2/KLOC-0 to August 24, there will be a heavy rainfall process from west to east in China, affecting 9 provinces and cities, with Sichuan and Henan having the strongest rainfall.

Zhengzhou, which has just experienced the "July 20" torrential rain disaster for one month and is still being rebuilt after the disaster, will encounter heavy rain or heavy rain again.

On the evening of August 18, the office of Henan Flood Control and Drought Relief Headquarters issued an urgent notice, asking all relevant units in various places to take precautions against the upcoming three rounds of heavy rainfall.

According to the forecast of the meteorological department of Henan Province, there was heavy rain or rainstorm in the north of the Yellow River and some counties and cities in Sanmenxia, Luoyang, Zhengzhou, Kaifeng, Xuchang, Shangqiu and other places on August 22, with local heavy rain. The precipitation in most areas is 70 ~ 100 mm, some counties and cities 150 ~ 180 mm, and some areas can reach 200 ~ 300 mm.

On the 20th, the sun was shining brightly. Our newspaper visited tunnels and subway stations in Zhengzhou, interviewed communities and hospitals, and found that flood control measures or preparations had been taken. Although the rainstorm was not as serious as the "July 20" forecast, many citizens had lingering fears. Many citizens said that they had bought safety hammers before, and some citizens even bought kayaks. On the evening of August 18, more citizens drove on the viaduct. Some Henan media said, "I heard that the rainstorm is coming, and the reaction of Zhengzhou people is too hard!"

Water baffles have been installed at the entrance of the subway and roadblocks have been installed at the entrance of the tunnel.

At noon on August 20th, Zhengzhou was sunny with the highest temperature of 32 degrees Celsius.

The paper randomly visited several stations of Zhengzhou Metro Line 3 and Line 5, and saw that the entrances and exits of the stations were all closed with iron gates. Behind the hollowed-out iron gate, a waterproof aluminum baffle with a height of 50-60 cm is installed, and sandbags are piled behind the baffle.

Install waterproof baffle at the entrance of subway. The pictures in this article are all from paper reporter Duan Yanchao.

On 20th 14: 00, the staff of People's Park Station on Line 3 told this newspaper that the station was under construction recently because it had three underground floors, so there were entrances and exits open. After receiving the rain warning on August 18, the subway took measures to install waterproof aluminum baffles at the entrances and exits of each station and pile sandbags. In his introduction, he conducted a flood control drill on Line 3 these two days. Although the subway has not resumed operation, the contents of the exercise still include comforting and evacuating passengers, preventing all entrances and exits from being flooded, and protecting facilities. Moreover, at 23: 00 on the 20th, the staff of each station of Line 3 will collectively conduct emergency drills for flood control.

According to the staff, she is not clear about other subway lines, which should be similar because the group has flood control requirements.

According to official website news, Zhengzhou Metro Group Co., Ltd. stopped the whole network of Zhengzhou Metro on August 19 due to the "July 20" torrential rain disaster. After all-out emergency repair, Zhengzhou Metro Line 4, Line 5 and Line 2 Phase II have realized no-load operation, and Line 1, Line 2 and suburban railway Phase I, which were stopped due to epidemic prevention and control, resumed no-load operation. Zhengzhou Metro is fully cooperating with the safety assessment and striving to realize passenger operation at an early date.

In Zhengzhou City, the reporter randomly observed that emergency roadblocks were set up at the entrance and exit of each tunnel, mostly telescopic roadblocks with a height of 50 to 60 cm. The Jingguang Road Tunnel (including South Road Tunnel, Middle Road Tunnel and North Road Tunnel), which caused six deaths in the "July 20" torrential rain disaster and attracted much attention, is ready to go. The reporter saw that each tunnel entrance and exit was not only equipped with a yellow railway barrier more than one meter high, but also equipped with a road cone, a red plastic water baffle and a warning light.

Roadblocks and waterproof baffles prepared at the tunnel entrance of Jingguang North Road.

In this regard, the staff of Zhengzhou Tunnel Comprehensive Management and Maintenance Center introduced that the center cooperated with the traffic police department to install disconnection facilities at the entrances and exits of eight tunnels (including Jingguang Road Tunnel) under its management. The newly installed road breaking facilities are mainly roadblocks for traffic control with the traffic police, and special personnel are arranged to be on duty when it rains. Once the tunnel is seriously flooded, the road will be broken in time.

The newspaper also noticed that warning signs were erected where there were construction pits on the road, and warning lights and road cones were erected in the direction of incoming vehicles.

Warning signs on the road

Hospitals, schools and communities have taken measures, and some citizens even bought kayaks.

Driving along the navigation road (Zijingshan Road to Jingguang Road), this newspaper saw sandbags piled at the gates of many enterprises on both sides of the road. The staff of a gas station near the intersection of Hanghai Road and Zijingshan told this reporter that the terrain of the gas station is relatively high, and the water almost flooded the business hall during the "July 20" rainstorm. In the face of the coming rainstorm, Zhengzhou Company has issued a notice. In addition to preparing flood control materials, the gas station also conducted a flood control drill on the morning of the 20th.

At the north entrance of Jingguang North Road Tunnel, the west gate (main entrance) of Jingguang Road Community in Erqi District has been locked, and sandbags with a height of one meter are piled at the door. The doorman told the newspaper that because the terrain of the community is high in the west and low in the east, the water that poured into the school flowed out from the east gate during the "July 20" rainstorm, so the water in the school was not deep, only one or twenty centimeters. This time, I heard that the Ministry of Education has issued flood control requirements, and the school has prepared flood control materials. When it rains, school leaders will be on duty to make plans.

A primary school with sandbags piled at the door.

During the "July 20" rainstorm, many hospitals in Zhengzhou were seriously affected. At present, Zhengzhou is in a critical period of anti-epidemic. As a designated hospital in COVID-19, the relevant person in charge of the Port Area Hospital of Zhengzhou First People's Hospital said that the hospital is in a high position and there is basically no water on the ground during the rainstorm. However, for the upcoming rainstorm, the hospital has made full preparations and plans for flood control. According to its introduction, the hospital has two CT cars outdoors, which are fully prepared for rain. More importantly, as a designated hospital, it is necessary to prevent the spread of pollution. , focus on strengthening the flood prevention preparation of medical waste storage and treatment points, and speed up the turnover and transfer. In addition, the protection of sewage treatment facilities has been strengthened to prevent backflow.

Mr. Zhang lives in a residential area in Guancheng District. During the "July 20" rainstorm, the community stopped water. Although the accumulated water on the roads outside the community is 30 cm higher than the entrance of the underground garage, fortunately, the property took timely measures to temporarily block the entrance of the garage with wooden boards, piled sandbags behind it, and sent people to be on duty 24 hours a day, so no vehicles in the community were affected. In the face of this rainstorm, the residential property reinforced the professional water baffles on both sides of the garage entrance. Once the rainstorm comes, it only takes 10 seconds, and if necessary, close the locking operation, and then put a sandbag next to it behind the water baffle to seal the gap.

"In view of the performance of the last flood property, it was time to pay the property fee recently, and I paid it immediately." Mr Zhang said with a smile.

Many interviewed Zhengzhou car owners said that after the "July 20" rainstorm, they all bought safety hammers, and some even bought life jackets.

Mr Cao even bought an inflatable kayak and three sets of life jackets. In the resettlement housing community where Mr. Cao lives, in the "7.20" rainstorm, the two-story underground garage was filled, many cars were flooded, and the water in the community had passed the waist. Until now, the community is still temporarily using electricity, the underground garage is still under maintenance, and the owners' vehicles are parked outside. This time, Mr. Cao is more worried. He specially called the property and got the answer that he was ready for flood control, but he always felt uneasy. He repeatedly asked where the sandbags were, and the property said they were in the warehouse. He urged them to pile up at the door as soon as possible.

When the paper passed an underground passage of the Beijing-Guangzhou Road viaduct, he saw seven or eight cars parked in the emergency lane of the underground passage, including BMW and Porsche, and no one was inside. According to Henan media reports, some citizens bluntly said that they were "panicked" when they saw the rainstorm coming again. The underground garages in some communities are empty, and the owners park their cars in high places. The roadside of Zi Long Hulongmen Bridge is already full of private cars. Some insurance companies remind car owners to take precautions. Some communities have prepared sandbags and pumps in advance and conducted flood control drills in advance. Residential areas with old and dangerous buildings have informed residents and businesses to evacuate to safe areas in advance.

The private car is parked on the viaduct.

However, some citizens expressed their calmness. "As long as there is awareness of prevention and measures, there is nothing terrible about heavy rain."