Typhoon "Niger" will be hit by heavy rain near Guangdong. Why do typhoons come so frequently this year?

Because the subtropical high is strong in the west this year, the generation and northward development of typhoons have been suppressed. Under the influence of the southern turning current, typhoons tend to move to South China, and Guangdong has a long coastline, so the probability of typhoons going straight to Guangdong is high. In addition, cold air activity increases in autumn. Typhoons encounter cold air, which usually leads to more violent precipitation, so typhoons are more prone to "malicious roles" in autumn.

Causes of typhoon formation:

Typhoon originated in tropical ocean, where the temperature is high and a large amount of seawater is evaporated into the air, forming a low pressure center. With the change of air pressure and the movement of the earth itself, the inflow of air also rotates, forming a counterclockwise air vortex, which is a tropical cyclone. As long as the temperature does not drop, this tropical cyclone will get stronger and stronger, and finally a typhoon will form.

Classification of typhoons:

In the past, China used to call the tropical cyclone formed on the tropical ocean surface above 26℃ a typhoon. According to its intensity, it is divided into six grades: tropical depression, tropical storm, strong tropical storm, typhoon, strong typhoon and super typhoon.

According to international practice, the maximum wind force near its center is divided into:

Tropical depression with maximum wind speed of 6-7, (10.8- 17. 1 m/s); ?

Tropical storm with maximum wind speed of 8-9 (17.2-24.4m/s);

Strong tropical storm, maximum wind speed 10 ~ 1 1, (24.5 ~ 32.6m/s);

Typhoon (typhoon), maximum wind speed 12 ~ 13, (32.7m/s ~ 41.4m/s);

Strong typhoon with maximum wind speed14 ~15 (41.5m/s ~ 50.9m/s);

Super typhoon with maximum wind speed ≥ 16 (≥5 1.0m/s).

The benefits of typhoons:

Typhoon has the following benefits for human beings:

First of all, typhoons bring people abundant fresh water. Typhoon brought a lot of rainfall to the coast of China, the coast of the Sea of Japan, India, Southeast Asia and the southeastern United States.

Secondly, the tropical and subtropical areas near the equator have the longest sunshine time, and the dry heat is unbearable. If there is no typhoon to dissipate heat in these areas, it will be hotter there and the surface sand shortage will be more serious. At the same time, the cold zone will be colder and the temperate zone will disappear. There will be no spring city like Kunming in China, and there will be no evergreen Guangzhou. "Beidacang" and Inner Mongolia grassland will also cease to exist.

Third, the typhoon can reach a top speed of more than 200 kilometers per hour, and it is invincible wherever it goes. This huge energy can directly cause disasters to mankind, but it also keeps the earth in thermal balance and makes mankind live and work in peace and contentment.

Fourth, typhoons can also increase fishing output. Every time a typhoon blows, it turns over the river, rolling up the nutrients in the river bottom and the sea, increasing the bait, attracting fish to gather near the water surface, and naturally increasing the catch.

Typhoon disaster:

Typhoon is a very destructive and disastrous weather system, but sometimes it can also play a beneficial role in eliminating drought. Its harmfulness mainly includes three aspects:

(1) Strong wind. The maximum wind force near the center of tropical cyclone reaching typhoon level is above 12.

② Heavy rain. Typhoon is one of the weather systems that bring heavy rain. The area where the typhoon passes may produce rainfall of 150 mm ~ 300 mm, and a few typhoons can directly or indirectly produce heavy rain above 1000mm, such as the heavy rain in southern Henan after tropical cyclone No.3 +0975 landed, which broke the rainfall record in some areas (Henan 75.8

③ Storm surge. Generally, typhoons will increase water in coastal waters, and the maximum water increase in coastal areas of Jiangsu Province can reach 3m. Typhoon "9608" and "97 1 1" increased water, which made Jiangsu's coastal areas along the Yangtze River have a super-historical climax.

Typhoon often brings stormy weather when crossing the border, causing huge waves on the sea surface, which seriously threatens the safety of navigation. After the typhoon landed, the storm surge may destroy crops and various building facilities, causing great losses to people's lives and property.

Anti-Taiwan:

resident

1. Listen, watch or visit typhoon warning information in time to understand the government's countermeasures against Taiwan.

2. Close the doors and windows and fix the structures that are easily blown by the wind.

3. Move from the shabby house to a safe place.

4. People in low-lying areas that may be flooded should be transferred in time.

5. Check whether the facilities such as circuits, fire fighting and gas are safe.

6 kindergartens and primary and secondary schools should take temporary avoidance measures and suspend classes when necessary.

7. Open-air collective activities or indoor large-scale gatherings should be cancelled in time and evacuation work should be done.

sea

1. Before the typhoon comes, the ship should obey the command and go to shelter immediately.

2. In case you can't escape or encounter a typhoon, you should contact the relevant departments on the shore for rescue in time.

3. While waiting for rescue, take the initiative to take emergency measures, and quickly and decisively take measures such as stopping (stagnation), bypassing (winding) and crossing (speed crossing) to leave the typhoon.

4. The calm wind and waves shortly after the strong typhoon may be the calm when the typhoon eye passes by. At this time, the owner of the berthing port must not go back to reinforce the ship in order to protect his property.

5. If conditions permit, the ship is equipped with modern equipment such as beacons, radio communicators and satellite phones.

6. In the absence of radio communication equipment, when ships or planes are found passing by, or when they are close to land, you can use objects to send out easy-to-detect distress signals in time, such as piling up the word "SOS", setting off fireworks, sending out acousto-optic signals, shaking brightly colored objects, etc.