WAVE-CISK对称不稳定谱点分布的半圆定理

采用滞弹性近似研究了WAVE-CISK下对称性扰动的谱点分布,得到了WAVE-CISK下对称不稳定扰动谱点分布的半圆定理,用其可估计该对称不稳定增长率的上界.发现存在WAVE-CISK时加热反馈和层结参数对该不稳定的增长率均有重要影响.WAVE-CISK加热反馈越强、基流的垂直切变越大,扰动的垂直结构越简单则该不稳定增长率的上界就越大.存在WAVE-CISK时滞弹性近似下的对称不稳定发生的条件也较Boussinesq近似下的更苛刻.

Semicircle Theorem on the Spectral Distribution in Symmetrical Instability with Wave-Cisk

The spectral distribution of symmetrical distribution with Wave-CISK under anelastic approximation is studied. The semicircle theorem on the spectral distribution in symmetrical instability with Wave-CISK is obtained. The theorem can estimate the supremum of the growth rate of the instability. It is found that under Wave-CISK, the heating feedback and stratification stability parameter have important influences on the growth rate. The stronger the heating feedback and vertical shear of basic flow, the larger the supremun of the growth rate. Also the simpler the structure of disturbance in vertical direction, the larger the supremum. Condition to make symmetric instability under the anelastic approximation is harsher than under Boussinesq approximation.