The Effect of Asymmetric Wind Structures of Tropical Cyclones on Their Tracks

1. IntroductionStudies on the tracks of tropical cyclones (TCs)have been one of the core problems in TC dynamics.In earlier researches, TCs are often viewed aspoint vortices, Rankine vortices. For example, Yeh(1950) and Kuo (1969), adopting dynamical methods,studied the motions of TCs and the effects of environ-ments. Their findings indicated that the motion tracksof TCs are characterized by cyclonic trochoidal oscil-lations.Syono (1955), by solving the barotropic vorticityequation, obta…

The Effect of Asymmetric Wind Structures of Tropical Cyclones on Their Tracks

A model is proposed relating a variety of factors of tropical cyclones (TCs) to their tracks, and attentions are paid to the influence of the asymmetric wind structures of TCs. Ideal numerical calculation shows that the asymmetric wind structures of TCs have conspicuous influence on their motion tracks. When moving due westward initially, an axisymmetric TC will deflect right, and the overall trend is eastward. When it is asymmetric but the asymmetry is not sharp, wherever the area of maximum wind is, the TC deflects northwest first, and then, to various areas depending on the positions of the areas of maximum wind, i.e. for the area of maximum wind in Quadrant I, to the southeast; for in Quadrant to the northeast; for in Quadrant to the northwest; for in Quadrant to the southwest. And in the above four cases, the TC tracks are all accompanied by clockwise looping motions. With the asymmetry of the TC intensifiying, the track of the TC motion will be stretched further. For the area of maximum wind in Quadrants the TC tracks are still accompanied by clockwise looping motions; for the area of maximum wind in Quadrants the TC tracks become oscillatory, without clockwise looping motions.