Fujiwhara effect
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The Fujiwhara effect, sometimes referred to as the Fujiwara effect, Fujiwara interaction or binary interaction, is a phenomenon that occurs when two nearby cyclonic vortices move around each other and close the distance between the circulations of their corresponding low-pressure areas. The effect is named after Sakuhei Fujiwara, the Japanese meteorologist who initially described the effect. Binary interaction of smaller circulations can cause the development of a larger cyclone, or cause two cyclones to merge into one. Extratropical cyclones typically engage in binary interaction when within Template:Convert of one another, while tropical cyclones typically interact within Template:Convert of each other.
Description
When cyclones are in proximity of one another, their centers will circle each other cyclonically (counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere)[2] about a point between the two systems due to their cyclonic wind circulations. The two vortices will be attracted to each other, and eventually spiral into the center point and merge. It has not been agreed upon whether this is due to the divergent portion of the wind or vorticity advection.[3] When the two vortices are of unequal size, the larger vortex will tend to dominate the interaction, and the smaller vortex will circle around it. The effect is named after Sakuhei Fujiwhara, the Japanese meteorologist who initially described it in a 1921 paper about the motion of vortices in water.[4][5]
Tropical cyclones
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Tropical cyclones can form when smaller circulations within the Intertropical Convergence Zone merge.[6] The effect is often mentioned in relation to the motion of tropical cyclones, although the final merging of the two storms is uncommon. The effect becomes noticeable when they approach within Template:Convert of each other. Rotation rates within binary pairs accelerate when tropical cyclones close within Template:Convert of each other.[7] Merger of the two systems (or shearing out of one of the pair) becomes realized when they are within Template:Convert of one another.[8]
Extratropical cyclones
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See also
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References
External links
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