中文摘要：

用数值试验的方法，应用强迫耗散准地转正压涡度方程的全球谱模式，在方程中考虑了偶（单）极子的热力强迫作用，并在三个行星波准共振的条件下，模式共积分90d，得到：在偶、单极强迫热源和基本气流强度的共同作用下，三个行星波之间存在很强的波．波相互作用，且波动振荡呈现准双周和季节内振荡。同时偶、单极强迫源及基本气流的强度变化对中高纬大气的低频振荡调制作用不同。在准共振三波流函数场随时间变化的试验结果中，进一步证实了中高纬大气存在较好的低频振荡。

英文摘要：

The numerical experiments on forcing dissipation and heating response of dipole （unipole） are carded out using global spectral model of quasi-geostrophic barotropic vorticity equation. For every experiment model integration is run for 90 days on the condition of three waves quasi-resonance. The results are given as follows： Under the effects of dipole （unipole） forcing source and basic flow intensity, there exist strong interaction among the three planetary waves, and there also exist quasi-two-week and intra-seasonal oscillation of the three planetary waves. In the meantime, the changes in the intensity of dipole or unipole forcing source and basic flow have different frequency modulation effects on LFO in the mid-high latitudes. The results of the stream function field of three quasi-resonant waves evolving with time proves further that the low-frequency oscillation exists in extratropical latitude.