关于热带大气低频振荡的一个简单模式与数值模拟

本文首先从观测事实分析了热带大气的低频振荡现象，然后从理论上加以研究。为此，本文建立了一个包括触发热源和CISK机制的三维线性模式，用此模式讨论了热带大气低频振荡的性质、结构、传播和动力学机制。从模式的计算结果得到了周期为30d左右以大约9 m/s的速度向东传播的低频振荡现象，这种振荡为Kelvin波型的响应和向西传播的Rossby波型的响应的结合。计算还表明，这种振荡的周期与触发热源的周期关系不大，这说明了热带大气的低频振荡是大气自身的固有振荡，它是大尺度运动与对流凝结加热相互作用的结果。

A Simple Model and Numerical Simulation of Low-Frequency Oscillation in the Tropical Atmosphere

In this paper, the low-frequency oscillation of the tropical atmosphere is first analyzed with.observational facts and is then studicd theoretically. A thwtimensional linear model inclnding the triggering heat source and the CISK mechanism is constructed to discuss the features, structure, propa-gation and dynamical mechanism of low-frequency osoillation in the tropical atmosphere. From the modelling rcsults, we obtain a low-frequency oscillation with a periiod of about 30 days which Propa gates eastward with a speed of about 9 m s. The oscillation consists of a Kelvin-type response and a Rossby-type response which moves westward. The results also suggest that the Period of the oscillation is not relevant to the Period of the triggering heat souree. This shows that the low-frequcncy oedllahon of the tropieal atmosphere is an inherent oscillktho of the atmosphere itself and is indutal by the interaction between a large scale motion and condensation heating in the tropics.