Traditional Culture Encyclopedia - Weather forecast - What are the main areas and causes of typhoons in China?

What are the main areas and causes of typhoons in China?

I. Main distribution

The northern part of the South China Sea in China, the Taiwan Province Strait, Taiwan Province Province and its eastern coast, the western part of the East China Sea and the Yellow Sea are the high-frequency areas where typhoons pass.

Second, the causes

In tropical oceans, seawater is easily evaporated into water vapor after being directly exposed to sunlight. So compared with land, the temperature and air humidity above the ocean are much higher. According to Dayang. Com, this kind of air expands due to high temperature, resulting in lower density and weight, while the wind near the equator is weak, so it is easy to rise and convection occurs.

At the same time, the surrounding cold air flows in to replenish and then rises, so that the whole air column is air with higher temperature, lighter weight and lower density, forming the so-called "tropical depression".

The air flows from high pressure to low pressure, and the air with higher pressure around it flows to low pressure, which forms the wind.

The rotation and revolution of the earth form distinct seasons and days and nights, and the formation of typhoons is also related to it. With the rotation of the earth, the direct point of the sun moves to the northern hemisphere through the equator in summer.

At this time, the southeast trade wind of the southern hemisphere ocean will also jump over the equator and become the southwest monsoon of the northern hemisphere. When the southwest monsoon meets the northeast trade wind, which is already active in the northern hemisphere, it will increase air convection and cause fluctuations and vortices.

When the convection in the air becomes stronger and stronger, the vortex deepens and the surrounding air flows faster and faster, the wind will become stronger and stronger. When the wind speed reaches or exceeds17.2m per second, a typhoon is formed.

The impact of typhoon on China;

China is one of the few countries in the world seriously affected by typhoons. Strong winds, heavy rains and storm surges brought by typhoons pose a serious threat to people's lives and property.

The typhoon that landed in China, the average maximum wind speed in Taiwan Province Province was 43m/s in August, and it also reached the level of strong typhoon in Taiwan Province Province in other months. Followed by landing in Zhejiang in August, with an average maximum wind speed of 41m/s.

Although most typhoons landed in Guangdong, the average maximum wind speed was not strong. The typhoon that landed in Hainan Island in June+10/October, 5438 was strong, with an average maximum wind speed of 36 m/s. ..

Typhoons landing in Fujian are often weakened by Taiwan Province Province first, and the strongest landing typhoon appears in September, with an average maximum wind speed of 31m/s.

Except Xinjiang, all provinces, municipalities and autonomous regions in China were directly or indirectly affected by typhoons, which led to heavy rains. Typhoon is the influence system of 1 1 provinces and cities in China.

Extreme rainstorms with precipitation exceeding 1000 mm in China in the next seven days, six of which are caused by typhoons. The rainstorm caused by typhoon (Nina) in Henan province 1975, the maximum center 1 hour, 1 89.5mm,1day,1005.0mm, five-day rainfall163/kl. ..

Typhoon rainfall also has its advantages in agricultural production, which can alleviate drought or alleviate drought. Typhoon is one of the precipitation systems in China. The typhoon precipitation in the southeast coastal provinces accounts for about 20 ~ 30% of the annual total, and it can reach more than half from July to September.