Fujian and Zhejiang should deal with the "double typhoon" attack. What is the double typhoon effect?

Double typhoon effect (also known as Fujiwara effect) means that when two typhoons approach, they will form a ring around the connected axes and rotate counterclockwise. The center and position of rotation are determined by the relative mass of two typhoons and the intensity of typhoon circulation. When rotating, under normal circumstances, one walks fast and the other walks slowly, and sometimes it may merge into one.

This phenomenon was first observed by Japanese meteorologist Dr. Fujiwara in the current experiment of 1923, so it is also called Fujiwara phenomenon. On the afternoon of August 1 August, 2065438, a rare double typhoon landed in Chinese mainland on the same day, and Jiangsu Province launched a Class III emergency response against typhoon.

Causes of double typhoon effect

Fujiwara effect originated from a series of vortex experiments and observations made by Japanese meteorologist Dr. Fujiwara from 192 1 to 1923. He found that two cyclone vortexes that are very close to each other will interact and move in the direction of the cyclone along the axis formed by the centers of the two. These two vortices tend to approach each other and merge.

Although the double typhoon effect is defined as two tropical cyclones rotating around the same center, it can be ever-changing, not necessarily two tropical cyclones rotating around the same center: it can be that one tropical cyclone completely dominates the moving direction of the other, it can also be that two tropical cyclones are staggered, one can follow the other, or even there is no double typhoon effect between them. Therefore, whenever two tropical cyclones approach each other, it is usually difficult to predict the path of tropical cyclones.

The term "double typhoon effect" is a proper term for the interaction of tropical cyclones in Asia. In the North Atlantic, the interaction of tropical cyclones is called "windmill cyclone".

Double typhoon effect classification

Generally speaking, the interaction of the most common tropical cyclones can be divided into three categories:

Unidirectional influence type

When a generally strong tropical cyclone and a generally weak tropical cyclone approach each other, the strong tropical cyclone will dominate the path of the weak tropical cyclone and make the weak tropical cyclone rotate counterclockwise around it. For example, the impact of typhoon Tim 1994 on tropical storm Vanessa.

Interaction type

When the intensity of two tropical cyclones is equal, they will rotate around a concentric center, and they will not get rid of the mutual influence until they are influenced by other weather systems or one of them is weakened. For example, 1986 Typhoon Wayne and Typhoon Na Wei, 2009 Typhoon Morakot and Swan, 20 10 Strong Tropical Storm Lion Mountain and Nanchuan, 201/kloc-0 Strong Tropical Storm Miley and Tropical Storm Hippocampus.

combined type

A stronger tropical cyclone may absorb a smaller tropical cyclone and make it a part of its own circulation. It's like Maggie absorbed the low pressure area of the South China Sea at the beginning of 1999 (but only if the distance is close enough and the weak tropical cyclone is not affected by other weather systems).

What are the typhoon phenomena in history?

1983 Typhoon Aibei (8305) Tropical Storm Ben (8306) Tropical Storm Kaman (8307)

1985 typhoon pat (85 12) tropical storm ruby (85 13) typhoon skip (85 14)

Strong tropical storm Maria (0607), strong typhoon Sang Mei (0608) and strong tropical storm Baoxia (0609) in 2006.

20 10 strong tropical storm lion mountain (1006) strong typhoon compass (1007) tropical storm Nanchuan (1008)

20 1 1 Typhoon Shana (117) Tropical storm Haitang (1 165438) Typhoon Niger (165438)

20 12 tropical storm Sura (1209) tropical storm David (12 10) tropical storm anemone (12 165438) strong typhoon Libra (0)

20 13 typhoons "feite" and "danasi" are forming a rare double typhoon to land on the coast of Fujian.