[News Terms] The 'Fujiwara Effect' That Made Typhoon 'Khanun' Cross the Korean Peninsula

The 'Fujiwara effect' refers to the phenomenon where two tropical cyclones influence each other when they come close. It was first discovered by Japanese meteorologist Sakuhei Fujiwara in 1921.

Tropical cyclones (typhoons) usually move according to winds generated by nearby high-pressure systems or troughs, but when two tropical cyclones come within about 1000 to 1200 km of each other, their directions are determined by the rotational influence of both cyclones.

Powerful waves brought by Typhoon Khanun.
[Photo by Yonhap News]

Tropical cyclones rotate counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere, engaging in a struggle for dominance. When two typhoons meet, they exert pushing and pulling forces on each other. Each may change its course, or a smaller typhoon may be absorbed by a larger one, developing into a stronger typhoon.

In Korea, the 14th typhoon 'Denbin' and the 15th typhoon 'Bolaven' in August 2012 are representative cases of the Fujiwara effect. Denbin, which formed north of the Philippines, began moving northward east of Taiwan. However, influenced by Bolaven, which formed shortly after, Denbin's path shifted, rotating counterclockwise and making landfall south of Taiwan, while Bolaven made landfall on the Korean Peninsula first.

Denbin, which was predicted to dissipate after moving toward China, resumed its northward movement after Bolaven moved away and eventually made landfall on the Korean Peninsula. Korea suffered significant damage due to the consecutive impacts of these two typhoons.

The current 6th typhoon 'Khanun' and 7th typhoon 'Ran' are also exhibiting the Fujiwara effect. Ran, moving northwest toward the Japanese archipelago, is expected to approach the Ogasawara Islands around the 10th to 12th and possibly pass through Honshu next week.

The reason Khanun's northward speed was slow is due to the Fujiwara effect caused by Ran. As Ran and Khanun, which formed on the 9th, struggle, Ran exerts a force that slows Khanun's advance toward Korea or pushes it back toward China. Although the jet stream west of Korea strongly blocks Khanun from moving toward China, Khanun continues to exert force to move westward, slowing its northward progress and ultimately causing it to traverse the Korean Peninsula slowly.

This content was produced with the assistance of AI translation services.