Analysis On The Counterclockwise Rotate Unusual Track Of Tropical Cyclone

The environmental current, the asymmetric structure and the asymmetric convection system are viewed as three fundamental factors that influence TC track. The previous works on the framework of TC motion dynamics generally examine the effects of a single factor among the three, belonging to the single factor framework.As pointed out by Elsberry, the problem of tropical cyclone track prediction is made more difficult than the simple single factor description,because each of these components varies in time and interacts with each other. As a result, it is necessary to analyze the time-dependent characteristics of each factors and their interactions. In addition,there is not a general solution for the nonlinear problem.The current research is that analyzing typical instances from observational facts.The TC Meranti,the TC Saola and the TC Tembin are taken as typical instances in this paper.The time-dependent characteristics of the three factors and their interactions will be analyzed under the multiple-factor framework. Moreover,we need to combine forecasting of the track with nonlinear theory in order to get a deep insight into the abnormal track of tropical cyclone.For being advantageous for the discussion and analysis, the track of TC is divided into three stages:the phase I, the phase Ⅱ and the phaseⅢ.The results show that the environmental guiding flow plays a key role in the phase Ⅰ and the phaseⅢ, the asymmetric structure also has a certain influence in three phases.But it could not explain the counterclockwise loop. The asymmetrical parameter can characterize the asymmetric structure in order to know the track of TC. The formation of counterclockwise rotate track of TC is,to some degree ascribed to the asymmetric convection system. And the interaction between asymmetric convection system and TC can be divided into three types:firstly, the two vortices are quasi-steady in the binary vortex process.secondly, the vortices are merging in the binary vortex process.thirdly, the vortices are escaping in the binary vortex process.Rotation and escaping are related to the counterclockwise rotate track directly.Fractal theory is a branch of the nonlinear science,so we analysis three TC’s track by using it.The time-dependent characteristics of TC edge fractal dimension is phased. But the specific contact between the TC edge fractal dimension,the TC complex degree and the abnormal track is not clear.