圆形涡旋大气中的横波不稳定

讨论涡旋大气中,存在沿切向基流传播的横波型扰动,并采用数值方法讨论了柱坐标系下圆形涡旋系统斜压气流中这类扰动的不稳定,这是一类中尺度的重力惯性波的不稳定.研究了涡旋环境大气的层结稳定度参数N2、切向风垂直切变Vz、凝结潜热、涡旋特性及科里奥利参数f0对不稳定增长率的影响.圆形涡旋中同样存在横波不稳定的Eady模态和中尺度模态,得到了中尺度模态的扰动场分布特征:流场的不规则"猫眼"结构及慢速传播的扰动均集中在低层,而快速传播的扰动均集中在高层的扰动特征.

Transverse Wave Instability of Circular Vortex Atmosphere

The transverse wave disturbance along tangential base flow of circular vortex is discussed By using numerical method we study this instability of baroclinic flow which is mesoscale inertia wave instability on the cylindrical coordinate The influence of stratification stability N 2 , Coriolis parameter f 0 , the vertical shear of tangential wind z of the ambinent atmosphere and the latent heat on the growth rate of instability is studied From the above analysis and calculation, we can learn that there are Eady mode and mesoscale mode of transverse wave instability in circular vortex as well Furthermore we also learn that distribution character of mesoscale mode disturbance field of transverse wave instability, anomalistic "cats eye" structure of lower level and the character of the slowly spreading disturbance converges at low level and the quickly spreading disturbance converges at high level