Why are there so many typhoons and rainstorms along the northeast coast this year?
First, what are typhoons and rainstorms?
Typhoon is a kind of tropical cyclone, which is a low-pressure vortex that occurs on the surface of tropical or subtropical oceans. According to the definition of the World Meteorological Organization, a tropical cyclone center with sustained wind speed above 12 (i.e. 32.7m to 41.4m per second) is called a typhoon or hurricane. Different regions have different names. Generally speaking, tropical cyclones generated in the Pacific Ocean are called "typhoons". Tropical cyclones generated in the Atlantic Ocean are called hurricanes.
Rainstorm (English name Churchill rain；; Heavy rain; Storm) refers to rain with high precipitation intensity, which is often formed in cumulonimbus clouds. According to China's meteorological regulations, heavy rainfall with 24-hour precipitation exceeding 50 mm is called "rainstorm". According to its precipitation intensity, it is divided into three grades, namely, 24-hour precipitation of 50-99.9 mm is called "rainstorm", 100-249.9 mm is called "heavy rainstorm", and more than 250 mm is called "extraordinary rainstorm". However, due to the different characteristics of precipitation and topography, the standards of rainstorm and flood are different in different places.
Second, why are there so many typhoons and rainstorms along the northeast coast this year?
A typhoon is a "tropical cyclone" generated on the tropical or subtropical ocean surface, and its central sustained wind speed ranges from 12 to 13 (i.e. 32.7m to 41.4m per second).
As one of the countries most seriously affected by typhoons in the world, there are about 10 typhoons in China every year, which basically land all the way from the southeast coast to the west, mainly covering Fujian, Zhejiang, Guangdong, Jiangxi and other southern regions. This path movement originates from the "twitch" of the subtropical high.
In July and August, the subtropical high was in a strong period, and it controlled the middle and lower reaches of the Yangtze River in China after the westward extension was strengthened. In the control area, subsidence is the main movement, which is not conducive to the development of typhoons, just like building a barrier to the north of the Yangtze River, making it difficult for typhoons to "break through" and reach the farther north.
1. The intensity of typhoons this year is stronger than in previous years.
Although so far, only seven typhoons have been generated in the Pacific Ocean, which is obviously less than in previous years, there are six typhoons, all of which are typhoon-level, and four of them are super typhoons. Because the circulation of Typhoon Dusuri carries a large amount of water vapor, and the subtropical high is in the east, the pressure gradient between them will significantly enhance the east wind and southeast wind in the Beijing-Tianjin-Hebei region, and transport the water vapor near typhoon khanun in the western Pacific Ocean to the North China Plain for a long distance. At the same time, it will be blocked by Taihang Mountain in the west and Yanshan Mountain in the north, and the water vapor will be forced to rise, which is conducive to the condensation of water vapor into rain. The superposition of the above factors caused heavy rainfall in Beijing, Tianjin and Hebei.
There are many typhoons registered in the north this year.
Whether Du in front or typhoon khanun in the back, the main landing areas are in the north, with Du's invasion before and Kanu's water vapor supplement after, and two typhoons and heavy rains superimposed. This is related to the subtropical high this year. This year's subtropical high is distributed in blocks, forming a strong high-pressure dam along the eastern coast of China, making it difficult for typhoons to land.
This year's typhoon has a great influence.
Because this year's typhoon intensity is relatively large, the scope of influence is relatively large. For example, "Du Surui" was able to go all the way north this time, on the one hand, because of its super power when landing, and on the other hand, because of its special atmospheric situation formed after repeated tug-of-war with "subtropical high".
In other words, this high-pressure dam that once crossed the middle and lower reaches of the Yangtze River was pushed to North China and Huanghuai by Du's powerful residual circulation. In addition, the mountainous geographical environment in the western part of North China and the continuous water supply in Kanu triggered mountain torrents and mudslides, which led to the rapid rise of river water level and concentrated floods.
Rain, flood and disaster are superimposed. Judging from the disaster intensity, the direct losses and secondary disasters caused by this round of "typhoon storm" to the northern region can be called "once in a hundred years".
3. What should I do in case of typhoon and rainstorm?
(1) At home:
1. Properly handle flowerpots and sundries that are easily blown off by strong winds on the windowsill.
2. Close the doors and windows. In order to prevent the window glass from being shattered by strong wind and hurting people, you can stick a layer of film on the window glass, or stick it into a "meter" shape with tape and paper.
3, check whether the circuit, fire, gas and other facilities are safe, cut off the power supply and turn off the gas.
4. Prepare flashlights, candles and other lighting tools in advance, and reserve drinking water, food, medicines and related necessities to avoid going out to buy after water and electricity are cut off.
(2) Outdoor:
If you are outdoors, walk carefully and get to a safe building as soon as possible.
1, away from dangerous buildings, telephone poles, billboards, scaffolding, trees, iron towers and other places that are prone to collapse.
2. When you have to walk outdoors, bend down and walk slowly in an open place so that you can see the road clearly; When you are on a narrow bridge or high place, crawl forward; Stop at the corner.
Don't force your way through the flooded area, or you may fall into the pit. If there is a wire hanging near the stagnant water, it may be charged in the water.
4. stay away from the water shore. You can't go swimming at the seaside or watch the tide at the seaside. At this time, going out to sea is even more reckless.
③ When driving:
1, remember to slow down, keep the distance between cars, pay attention to the water on the road, and bypass the low-lying sections with water.
2. When you have to wade through, you should open the skylight in advance, roll down the window and drive in the stagnant water area. Use low speed, don't stop, don't shift gears.
3. If the vehicle can't restart the engine after sudden flameout, you should get off immediately.
4, found that the water is not at the height of the door, and continue to rise, we must decisively abandon the car.
5. During the typhoon, pay attention to the electronic signs on the road in real time to remind the road ahead.
6. In case of temporary traffic control, please obey the command.
Personal experience: I live in the south, and I have encountered many typhoons, but it has not reached the point of flooding. The flood in the north this year was unexpected, but I can clearly feel that there are indeed many typhoons this year, and they are still connected. But because of the typhoon, I feel that it is not very hot this summer, otherwise it will be above 35 degrees at every turn, and the sun is unbearable. I feel that there are more and more extreme weather now, so we should pay more attention to the prevention of typhoon days. In addition, the relevant areas should also pay attention to prevent flash floods and geological disasters that may be caused by heavy precipitation.