The path of the typhoon

The moving direction and speed of typhoon depends on the typhoon. The power is divided into internal force and external force.

Internal force refers to the northward and westward resultant force caused by the gap of Coriolis force because of north and south latitude difference in the scope of the typhoon. The greater the scope is, the stronger the wind speed, the greater the internal force.

External force is the environment force in the surrounding flow field in typhoon vortex, namely the guiding force brought by the high-pressure basic air flow in the northern hemisphere.

The internal force mainly works when the typhoon is formed, and the external force is the dominant force to control the movement of the typhoon, so the typhoon basically moves from east to west.

Due to the influence of the shape, position, intensity and other factors of the subtropical high, the path of typhoon becomes varied. For example, there are three generally ways the path of typhoon movement in the western Pacific region:

First, westward typhoon: it moves towards the west from the east of the Philippines, through the South China Sea and at last, lands in Hainan Island in China or the north of Vietnam land. The route happens mostly in October or November months. The typhoon in 2006 is a typical example.

The second, the landing typhoon: it moves from the sea to the northwest, crossing the Taiwan Strait and landing in Guangdong, Fujian and Zhejiang, and gradually reducing to low pressure. Such typhoons have the greatest impact on our country. In recent years, the two typhoons, "9015" and "9711", which have had the greatest impact on Jiangsu, are of this type, and typhoons in July and August are basically the same path

The third is parabolic typhoon: it first moves northwest. When it is close to east China along the sea area, it won’t land and then move torwards the northeast and Japan, whose path is in the shape of parabola. This path happens most in May or June months and from September to November after typhoon formation. Generally, it will remove from the source place and experience the evolution process of development, weakening and dying.

The circular vortex radius of a mature typhoon is usually 500~ 1000 km with the local level of 15~20 km. The typhoon consists of three parts that is the periphery, the maximum wind speed zone and the typhoon eye. The wind speed in the peripheral area increases from the outside, with spiral cloud belt and showery precipitation. The most intense precipitation occurred in the maximum wind speed area, with an average width of 8 ~ 19 km and there is a ring wall cloud between the area and the typhoon eye. The typhoon eye is in the center of typhoon and the most common form of typhoon is circular or oval shape, with diameter of about 10 ~ 70 km and an average of about 45 km. Typhoon weather is no wind, cloud and less dry and warm.