In this paper, free vortex fluctuations in barotropic quasi-equilibrium ocean model are studied. The results show that the forms of the solutions are wave packet and carrier frequency of wave package spreads westward. when only the west coast of the ocean is considered, the cartier frequency is continuous spectrum. However, when both east and west coasts of the ocean are taken into account, the cartier frequency is discrete spectrum. And both cases have the same characteristics: when carrier frequency is higher (period is shorter), the horizontal scale of wave packet is greater. For the excessive low-frequency fluctuations, then the quasi-equilibrium assumption will be no longer applied. The period of wave package carrier frequency in the model is about 26 d to 24 a. Because the friction is taken into account, the amplitude of wave packets decays exponentially with time and tends to 0. But the size of the coefficient of friction affects only the extent of wave packets decay without altering spatial structure. The solution of model tends to particular solution of forcing for atmospheric wind field. In the model, the nature of fluctuations is the quasi-equilibrium vortex wave, including quasi-geostrophic Rossby waves.%本文研究了正压准平衡海洋模型中的自由涡旋波.得到的主要结论有:该模型中的解为波包,其载频都是西传的.在仅考虑大洋西海岸时其载频频率是连续谱;而同时考虑大洋东、西海岸时则其为离散谱;且均有其载频频率越高(周期越短)其水平尺度越大的特点,对过分低频的波动,则会使准平衡的假定不再适用.模型中波包载频的周期约在26 d至24 a.因考虑了摩擦,波包的振幅随时间呈指数衰减,最终趋于0,但摩擦系数大小仅影响其衰减程度而不改变其空间结构,这样该模型的解最终趋于大气风场的强迫特解.该模型中波动的性质是准平衡的涡旋波,包括准地转的Rossby波.
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