What are the disasters caused by a family of tropical cyclones?

Tropical cyclones include tropical depressions, tropical storms, severe tropical storms, and typhoons or hurricanes. It is a huge warm-core cyclonic air vortex that occurs in the tropical ocean. While it rotates strongly, it moves forward at sea or lands on land, causing disastrous weather such as strong winds, heavy rain, huge waves, and storm surges. A typhoon or hurricane is the strongest tropical cyclone and the "biggest" among tropical cyclones.

The wind force of a tropical cyclone is strongest near the center. The average maximum wind force near the center is a tropical depression of magnitude 6 to 8, a tropical storm of magnitude 8 to 9, a severe tropical storm of magnitude 10 to 11, and the maximum wind force near the center of a typhoon or hurricane is magnitude 12 or above.

Tropical cyclones have different customary names in different regions. Those that occur in the Bay of Bengal and the Arabian Sea are called cyclonic storms; those that are close to the Philippines are called "Bagaos" or "Baguio winds"; those that appear in the southern Indian Ocean and the coastal waters of northern Australia are called "Weiliweili" ", meaning cunning, cunning and terrifying, repeating "power", telling people to be more vigilant; what happened on the Indian Ocean east of Madagascar is called "Mauritius".

For tropical cyclones with winds of Category 12 or above, international regulations are collectively referred to as typhoons or hurricanes. Typhoon originally refers to a severe tropical cyclone that occurs in the northwest Pacific and the South China Sea. Typhoon is originally the pronunciation of "gale" in Fuzhou dialect, and it means "turning around" in Arabic. Hurricanes generally apply to the Northeast Pacific and Atlantic Oceans. In Mayan mythology, "Hurricane" is a storm god with only one leg. Hurricanes in the Northeast Pacific along the coast from Mexico to Costa Rica are also called "Cordona left winds"; hurricanes in the West Indian Ocean Islands around the vernal and autumnal equinoxes are called "equinox storms". In the early days of China, typhoons were also called "hurricanes". During the Liu and Song Dynasties in the Southern Dynasty, Shen Huaiyuan recorded in "Nan Yue Zhi": "There are many hurricanes in Xi'an, and hurricanes are the winds from all directions; one is called fear of wind, which means fear. Typhoons often rise in June and July."

Typhoons are the most powerful tropical cyclones in terms of scope, power and impact on humans, and are the "eldest" in the tropical cyclone family. The radius of rotation is generally between 50 and 500 kilometers, and the height ranges from the sea surface to the bottom of the stratosphere. The central air pressure is very low, and the maximum wind speed near the center is more than 33 meters/second.

Typhoons usually occur in the vast warm tropical ocean with a water temperature of 26~27℃. There, the sea surface temperature is high, the water vapor content in the air is large, and heat is continuously released during the rising air convection. Under the action of the deflection force of the earth's rotation, a rotating warm-core air column is gradually formed, and eventually develops into a typhoon. Between 5° north and south latitude of the equator, although the sea water temperature is high, the deflection force of the earth's rotation is extremely small or zero, and typhoons cannot form. In the eastern part of the Southeast Pacific and the South Atlantic, no typhoons have been found so far due to low water temperatures and other reasons.

There are an average of about 45 typhoons in the global ocean every year, concentrated in eight sea areas including the northwest Pacific, Bay of Bengal, northeast Pacific, northwest Atlantic, Arabian Sea, southern Indian Ocean, southwest Pacific and northwest Australia. Among them, The largest number is in the northwest Pacific, with an average of 18.5 occurrences per year. These 18.5 typhoons were relatively concentrated in the central and northern parts of the South China Sea, east of the Philippines and near the Ryukyu Islands, in the ocean near the Mariana Islands and in the ocean near the Marshall Islands.

Typhoons in the northwest Pacific have a great impact on China's coastal areas. On average, there are 3 typhoons that make landfall every year, and there are 4.9 tropical storms and severe tropical storms that make landfall.