非线性准静止超长波的低频振荡及混沌特性

Low Frequency Oscillation and Chaotic Behaviors of a Nonlinear Quasi Stationary Ultra Long Wave System

利用混沌动力学的分析手段，对一个包含了地形、热力强迫以及耗散作用的准静止超长波动力系统的行为进行了初步探讨．结果表明，超长波平衡态的建立与加热场的结构有关．方程的定性分析及数值计算结果均表明，当超长波表现为周期行为时，其周期约为３０～４０ｄ，与低频振荡的频率相当．另外，还给出了一个与地形、耗散以及加热等因子有关的判据Ｃｒ，当Ｃｒ较小时系统出现周期态，而当Ｃｒ较大时系统出现混沌特征．

The behaviors of a nonlinear quasi stationary ultra long wave system which includes the topographic, thermal and dissipative effects are investigated with the methods of chaotic dynamics. It's found that depending upon the parameters the system can exhibit equilibrium states, periodic motions or even chaotic behaviors. The periodic motions have periods of about 30￣40 days, which are equivalent to the low frequency oscillation in the atmosphere. Based on the results of qualitative analysis, a criterion to judge the system's behaviors is proposed. The value of the criterion is related to the topography, dissipation and diabatic heating.