The result also shows , for the waves of 0 . 5 k < 6 , the nonlinear baroclinic subcritical instability easily occurs than the barotropic one . 2 . a two - layer quasi - geostrophic model forced by surface friction and radiative relaxation is used to study numerically the phenomenon of subcritical instability in baroclinic atmosphere 文中还指出对于0 . 5 k 6的中等波长的波动，非线性斜压亚临界不稳定比正压亚临界不稳定更易发生，这与实际大气中的情况类似。
Through diagnosing the connection in the nonlinear subcritical symmetric instability , linear symmetric stability , and rainfall , the article find : this rainfall process can be divided into three period , in which the nonlinear subcritical symmetric instability is the mechanism of the rainfall . the increase of rainfall has closely effection with the increase of the disturbance wind which often can be found before the increase of the disturbance wind which often can be found before the increase of the disturbance wind which often can be found before the increase of rainfall , so the increase of the nonlinear subcritical symmetric instability can make the rainfall increase 通过对非线性亚临界对称不稳定、线性对称不稳定和降水的关系的实况诊断分析发现：本次梅雨暴雨分为3大段过程，非线性亚临界对称不稳定可能是3段梅雨暴雨形成的重要机制。扰动风场增长与降水增长关系密切，扰动风场的增长会超前于降水的增长，非线性亚临界对称不稳定的增强可能使降水增强。从而初步验证了非线性亚临界对称不稳定理论。
From a nonlinear equation with boussinesq similarity on the f plane including friction dissociation and using a new kind of general energy as lyapunov function , we got the nonlinear subcritical symmetric instability criterion which a new kind of symmetric stability criterions . the nonlinear subcritical symmetric instability indicates that the larger amplitude disturb may cause the its instability to increase and then excite the mesoscale rainstorm 非线性亚临界对称不稳定判据是从含摩擦耗散的f平面上boussinesq近似下的非线性方程出发，以一种新的广义能量作为lyapunov函数，导得的一种新的对称稳定性判据，理论指出较大振幅的扰动可能出现非线性亚临界对称不稳定增长，从而激发中尺度暴雨扰动的生成。
