Abstract:
The progress concerning the physical mechanism responsible for changes of TC intensity has been made in some researches in terms of ideal models, which shows that meso-vortices located initially near the radius of maximum velocity of a TC may, in the way of the inward propagation of vorticity, form a new concentration of vorticity in the inner area leading TC increasing. The researches of this kind generally do not take the environmental flows into consideration and can be attributed to the category of systems of double scale with TC and meso-vortices.The systems in study are extended to ones with four-scale coexistence ( subtropical high, TC, mesoβand meso γvortices). A shallow-water equation Model was integrated on a betaplane centered at 20oN to study the typhoon self organization and its intensity change in the systems. The results show (1) a new TC exhibits the southwest to the initial typhoon (TC A), via self organization, when TC A travels to the northwest and tends to gradually weaken, after TC A extinguished, the new TC maintains its intensity corresponding to one that TC A had initially, and continues to move to the northwest, and (2) the total number and positions of the initial meso γvortices can influence the intensity of the self-organized TC obviously, and the possible mechanism is as follows: the different interaction between meso γ and meso βvortices may result in the various consequences of the interaction of two meso βvortices, merging together or departing away, and the interaction of meso βvortices can bring the change of intensity and track of self organized TC.