摩擦作用对西南低涡扰动的影响

西南低涡是对流层下层的中尺度扰动。本文在零级近似条件下,采用p坐标系的基本方程组,在边界层内设计两层模式。通过一定的简化方程组后,得到:当Z≤1/2kL~2/(μ~2Knu~*)] 时,摩擦效应具有二重性,一方面使扰动减弱;另一方面使扰动增强,而前者的影响略大于后者,最终使扰动消失。频率随高度Z的降低而增加。当Z>1/2kL~2/(μ~2Knμ~*)]时,摩擦作用甚微,几乎可以忽略不计。频率虽然有两个值,但随高度Z的增加,他们趋于一个常值。

THE FRICTION EFFECTS ON THE DISTURBANCE OF SOUTH-WEST VORTEX

The SOUTH-WEST VORTEX is a nieso-scale disturbance in the lower troposphere, p coordinate basic equations under zero-grade approximation condition are used and two level models are designed in the boundary layer in this paper. After simpling the equations, when Z is not greater than certain value the double characteristics of the friction effect have been found. On one hand , it makes the disturbance, On another hand, it makes the disturbance increase. Furthermore, the former is stronger than the latter. Finally, the friction effect makes the disturbance disappear, and the frequency increases with the Z decreasing. When Z is greater than certain value the friction effect is so little that it can be neglected. Though we have two frequencies, they tend to be constant .while Z increasing.