A study of numerical modeling of tropical cyclones and formation

在本研究中，基于作者开发的非静力轴对称模式和具有积云尺度参数化的三维静力模式两种模式。为了了解热带气旋的形成机制和中尺度结构，人们进行了大量的数值试验。至于模型的改进。为了更好地模拟热带气旋的中尺度结构，对静力模式中参数化对流放热的垂直分布进行了改进，并通过数值试验了解热带辐合区热带气旋的形成过程。积云对流的中尺度组织对于涡旋的形成和加强是必不可少的。实验较好地模拟了涡旋东南部的大风、中尺度有组织对流的气旋性旋转等中尺度结构。对风场和温场的中尺度结构进行了较为详细的分析。数值实验还模拟和理解了赤道地区Rossby模和Kelvin模分离的过程。一个涡旋从罗斯比模式发展而来，并转化为热带气旋。

In this study, based on two types of models such as a non-hydrostatic axi-symmetric model which can resolve cumulus-scale motion and a three-dimensional hydrostatic model with cumulus-scale parameterization which the author developed. many numerical experiments have been performed in order to understand the mechanism of tropical cyclone formation and mesoscale structure. As for model improvement. vertical distribution of heat released by parameterized convection in the hydrostatic model was improved to get better simulation of mesoscale structure of tropical cyclones.Numerical experiments were performed to understand the formation process of tropical cyclones in intertropical convergence zone. Meso-scale organization of cumulus convection is found to be essential to formation of a vortex and its intensification. In this experiment mesoscale structure such as strong winds located at the southeastern portion of the vortex and cyclonic rotation of mesoscale organized convection were simulated well. The mesoscale structure of wind and temperature fields were analyzed in some detail. Numerical experiments were also performed to simulate and understand the process where Rossby mode is separated from Kelvin mode in the equatorial area. A vortex developed from a Rossby mode and it transformed into a tropical cyclone.