A tropical storm is a huge vortex of air that occurs on the tropical ocean. It spins rapidly like a top. Americans call it "hurricane", Australia calls it "powerful", and in meteorology it is called For "tropical cyclone" or "tropical storm". Tropical storms cause losses of up to US$6 billion to US$7 billion around the world every year, and the loss of life caused by storm surges, heavy rains, floods, and winds accounts for 60% of all natural disasters.
The northwest Pacific Ocean, which borders China, is the most unstable ocean in the world and is the "heaviest disaster area" for natural disasters. Every year in midsummer and early autumn, the southeastern coast of China is often hit by tropical storms. Among them, there are nearly 20 tropical storms that cause disasters every year, which is equivalent to 4 times that of the United States and 30 times that of Russia. Tropical storms are the most serious disastrous weather in my country's coastal areas.
Tropical storms originate in the tropical ocean. Because the temperature and humidity are high there, a large amount of hot and humid air rises to high altitudes, condenses into rain, and releases a large amount of heat energy, which again heats the air on the ocean surface; a large amount of water vapor evaporates from the ocean surface and rises to high altitudes. This back-and-forth cycle gradually forms a cyclone center with very low central air pressure and a large amount of air flowing toward the low-pressure area.
The height of tropical storms is generally above 9 kilometers. The maximum wind speed of tropical storms is generally more than 40 to 60 meters/second, and individual strong tropical storms can reach 110 meters/second. During a tropical storm, the rainfall can reach 200 to 300 mm, sometimes as high as 1,000 mm. As a result, tropical storms often experience violent storms and cause floods. Tropical Storm No. 3, which occurred in 1975, caused heavy rains and floods in more than 10 provinces in eastern China. Henan Province was the worst affected. The center of the heavy rain happened to be located upstream of the two reservoirs, causing the reservoirs to burst. Water tongues more than 10 meters high poured down like giant dragons. A large number of farmland and cottages were flooded. More than 100 kilometers of the Beijing-Guangzhou Railway were washed away. , causing great casualties of humans and animals.
In recent years, China has entered the international advanced ranks in the research and prediction of marine disasters. 280 tide gauge stations have been built along the coast and on islands, making it the highest density monitoring station network in the world. It is one of the countries that has successfully issued severe storm surge warnings many times, which plays an important role in disaster prevention and relief.