Fujiwhara effect

The interaction between two tropical cyclones that occurs when the distance between them is less than about 1500 kilometers. Under such circumstances, both systems begin to trace a kind of dance, made evident in satellite image sequences. If the two tropical cyclones are of comparable size, they begin to orbit around the midpoint of the imaginary line joining their centers. If one of the cyclones is significantly larger than the other, the latter begins to orbit around the former, eventually being absorbed by it and a single system forming. The phenomenon bears that name in honor of the Japanese meteorologist Sakuhei Fujiwhara (1884-1950), who described it in the early 1920s, after observing it in experiments he carried out with two water vortices.