Mechansism of the Impact of the Cyclone System Induced by the Taiwan Island Topography on Tropical Cyclone Unusual Motion
台湾岛地形诱生次级环流系统对热带气旋异常运动的影响机制

The present paper analyzes statistically the temporal and spatial variation of the movement, structure and intensity of the tropical cyclone (TC) before and after it passes Taiwan Island, Hainan Island, Luzon Island, the Philippines, Islands of Japan and Korea Peninsula The result shows that the left-turning (deviate to the left of pre-track) probability of TC motion is the largest around Taiwan Island Furthermore, Taiwan is a high-frequency area to occur the induced cyclone Using the numerical simulation in which the ideal easterly and westerly wind are considered to be the background field, this paper studies the interaction between the island topographical forcing and the environmental flow field around Taiwan Island and its impact on the turning of tropical cyclone The results show that the interaction among island topographical forcing, environmental field and tropical cyclone vortex has influence on the sudden turning of the tropical cyclone track Thus the Taiwan topography has the positive effect on inducing a dipole difference vortex in the environment field, which will result in the sudden turning of the motional direction of tropical cyclones of approaching the island Besides, the island topography has significantly different effects on tropical cyclone motion under different basic flow conditions