东海地区温带气旋爆发性发展的动力学分析

本文对东海地区两个气旋波的爆发性发展过程进行了动力学分析。结果表明:明显的对流层中下部增温、增温以及不稳定的大气层结和强高空西风急流,及其有关的次级环流的作用是气旋爆发性发展的重要条件。在气旋爆发性发展过程中,上升运动、正涡度以及高空辐散和低空辐合的散度场皆达到最强。加热场的计算也表明非绝热加热特别是凝结潜热释放也在气旋爆发时刻达到最强,最大加热区位于气旋的东北象限内。这时涡动动能的增加十分显著,它主要是由涡动有效位能向涡动动能的转换造成,这说明气旋的爆发性发展是与斜压发展密切有关。

A DYNAMIC STUDY OF TWO EXPLOSIVELY DEEPENING CYCLONES OVER THE EAST CHINA SEA

This study investigates two explosively deepening cyclones over the East China Sea. The principal results are the following: Marked temperature and moisture increase in the lower-middle troposhere, unstable atmospheric stratification and strong westerly jet stream and its associated secondary circulation are important conditions favorable to explosive development of the cyclones. The strongest vertical motion, positive vorticity and upper level divergence and low level convergence were observed in explosive developmental process of the cyclones. Diabatic heating, specifically latent heat release is very crucial to its explosively deepening. The largest heating is located in northeast sector of the cyclones. Increase in the eddy kinetic energy is very marked during their explosively deepening stages. It was mainly contributed f rom the conversion of the eddy available potential energy to eddy kinetic energy. This indicates that explosive development of the cyclones is closely related to baroclinic development.