对称不稳定与初始扰动尺度关系的数值研究

THE NUMERICAL STUDY ON THE RELATION BETWEEN SYMMETRICAL INSTABILITY AND THE SCALE OF INITIAL DISTURBANCE

利用一个二维非弹性非静力的数值模式,讨论了初始扰动的尺度对于对称不稳定发展的影响。结果表明:虽然对称不稳定是β-中尺度的不稳定,但其不一定必须由β-中尺度的扰动来激发;由不同水平尺度的扰动所激发的倾斜环流有不同的特点;对称不稳定倾斜环流可能存在最小临界尺度;对称不稳定的发展存在最优扰动水平尺度,而扰动的垂直尺度对于对称不稳定的发展影响不大。

An anelastic and non-hydrostatic two-dimensional numerical model is used to study the influence of initial disturbances scale on the development of symmetrical instability. The results show that: The symmetrical instability does not have to be stirred by horizontal disturbance of correspondent scale of the symmetrical instability; the slant circulations, which are stirred by disturbances of different scales, have different specialties; there may be a minimum critical scale in symmetrical instability slant circulations; there is also an optimal horizontal scale to the development of symmetrical instability, while the vertical scale of disturbance throws less influence on symmetrical instability.