斜压大气中基本气流与扰动的若干制约过程

将涡度方程及绝热方程分离变量,化成非线性常微分方程组,以Runge-Kutta法在电子计算机上进行数值积分。从所得的结果中看出:基本气流与扰动是相互制约的,基本气流的变化有准周期性,具有10—13天不等的周期,在各个循环中,基本气流增长及减弱的速率也很不一样。波数为6的扰动,变化周期为11—13天,振幅变化近于正弦曲线;波数为4的扰动,其振幅变化较复杂;波数为2的扰动,变化周期为3天。波数为6的扰动,上下层同时发展或同时阻尼,但波数为4及2的扰动,上下层的变化趋势刚好相反。 最后从所得的结果中看到:对于非线性方程,如果初值不同,那么解的平均周期也不同。

THE INTERACTION BETWEEN BASIC CURRENT AND DISTURBANCES IN THE BAROCLINIC ATMOSPHERE

The vorticity equation and adiabatic equation are converted into a set of nonlinear ordinary differential equations which have been integrated on the electronic computer by using the Runge-Kutta method. The results obtained show that the basic current and disturbances constrain each other, that the basic current alters quasi-periodically with periods of 10 to 13 days, and that the rate of change of basic current in each cycle is .quite different. The disturbances of wave number six vary sinusoidally with a period of 11 to 13 days, the evolution of the disturbances of wave number four is complicated, and the disturbances of wave number two has a period of variation of about 3 days. T'he disturbances of wave number six develop or damp at the upper and lower levels simultaneously, but the evolution of the disturbances of wave number four or two at the upper and lower levels have the opposite trend. Finally, the results obtained show that the solutions of different initial values possess quite different mean periods of index cycles.