登陆台风衰减与变性过程的对比研究

A Comparative Diagnosis Study for the Decay and Modification Process of a Landing Typhoon

本文对登陆台风Freda的衰减和变性阶段进行了水汽、动能的对比诊断研究,结果表明,水汽供应条件对于台风登陆后的强度变化十分重要。台风北上过程中,副高边缘的偏南低空急流是最主要的水汽输送带。台风登陆后在衰减过程中,可看作是一个动能的“准封闭系统”,次网格尺度效应及摩擦作用是台风衰减的主要因子;变性阶段,在对流层高层有大量的动能输出,次网格尺度效应成了重要的动能源,台风与西风带相互作用时的动能平衡与温带气旋类似。

This paper presents a comparative diagnosis on water vapour and kinetic energy for the decay and modification process of a landing typhoon. The results show that the supply condition of water vapour affected strongly the intensity of the landing typhoon. The low-jet between the typhoon and a subtropical high was a primary transport belt of water vapour when the typhoon moved northward. In the decay process the landing typhoon could be considereu as a 'quasi- closed' system in kinetic energy. The subgrid scale effect and friction were the main dissipation factors. However, during the modification process, lots of kinetic energy were transported outward in the upper troposphere, and the subgrid scale effect became important in kinetic energy supply. when the typhoon interacted with westlies its kinetic energy budget was similar to those of extratropical cyclones.