非热成风平衡基流的对称不稳定及在涡旋大气中的动力诊断

从湿大气的绝热，无粘，包辛内斯克近似的二维线性化方程组出发，考虑基本气流民风不平衡，在经典的对称不稳定理论基础上推导出修正了的对称不稳定判据，发现基流热成风不平衡在一定条件下有利于对称不稳定发展。同时根据推导出的判据，利用高分辨率的模式输出资料，对一次飓风过程作了对称不稳定的动力诊断，发现对称不稳定是飓风眼壁中深厚倾斜上升运动产生的可能机制。

The Symmetry Instability of the Thermal Wind Non-Equilibrium Basic Flow and its Dynamical Diagnosis in the Vortex Atmosphere

In this paper , a modif ied symmet ry instability criterio n for thermal w ind no n-equil ibrium basic flow is deduced by using tw o-dimensio nal liner equat ions w ith Bo ussinesq approx imat ion of moist air . It is fo und that the thermal w ind non-equilibrium o f the basic flow is favourable for the development of symmetr y instability under cer tain co ndit ions. Then, the symmet ry instabil ity of a hurricane w ith this criterion is diagnosed, and the r esult s show that the symmet ry instability may serve as the mechanism for the dev elo pment of the slantw ise updraf t in the ey ew all .