On The Internal Spatio-Temporal Variety Traits And The Correlative Dynamic Mechanisms Of Typhoon Ewiniar(0603)

Several significant studies on Tropical Cyclone (TC) home and abroad has been reviewed comprehensively, including the researches on intensity variety and the internal dynamic trait of TC.On the basis of the studies above, a typical general TC, Ewiniar (2006), has been simulated by the Weather Research and Forecast Model (WRF) version 2.2 and the Moving-Nest technology and Tow-Way Nest Run. After that, a simple initial analysis on its substantial characteristics such as its moving trace and wind field has been presented in order to confirm the validity of the simulation, especially the intense wind, the most important feature of the sample.Reveal the asymmetric qualities of spatio-temporal distribution of internal perturbation in Ewiniar, by virtual of statistics methods including Dispersed Power spectrum Analysis (DPS), Continuous Power spectrum Analysis (CPS) and Most Entropy spectrum Estimate (MES). As a result, the main conclusions of that are included. Above all, the tangential Long-Wave component is dominant via the DPS. And the Long-Wave component would take out more proportion in the adjacent area to the eye of Ewiniar and somewhat less one in the outer area generally speaking. In the next place, the oscillation extracted by CPS and MES in the left and right side near the moving path is obvious asymmetrical, which mainly behaves in the inner of typhoon eyewall at middle-high level of the troposphere and is more inconspicuous in the outer and low level. But the long-period oscillation would dominate the inner area of typhoon eyewall at low level of troposphere.What's more, an consequent discussion on the reason of those phenomenon has been promoted by the means of WKBJ theory, which comes a conclusion that the strong non-adiabatic heating of convective activity in the inner area of TC could tune the frequency of Vortex Rossby Wave (VRW), bringing about the asymmetry distribution of oscillation traits in the inner area of TC, where the lower-frequency oscillation would form in the situation of intense heating, and the higher-frequency one would form in the one of weak heating as well.A Logarithmic-spiral model for the development of Mesoscale perturbation instability in vortex systems with vertical-sheared basic flow based on the theories of spiral-wave and Mesoscale hereotropic instability is established. Adiabatic frictionless linear disturbance Boussinesq equations in natural coordinates built along the spiral propagation path of disturbances are derived. And the unstable spiral development of Mesoscale disturbance, so called Spiral-Hereotropic instability, in the ideal vortex with vertical-sheared basic flow is studied by the numerical discretization method. Further more the influence of basic flow parameters of the vortex on the characteristics of the spiral instability systems is discussed. It is argued that unstable disturbances in the vortex with the vertical-sheared basic flow are capable to develop into the spiral bands like trailing Logarithm-spiral in sharp.