Finite-Amplitude Baroclinic Waves in a Continuous Model of the Atmosphere
Finite-Amplitude Baroclinic Waves in a Continuous Model of the Atmosphere
复制标题
大气连续模型中的有限振幅斜压波
DOI：
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发表时间：
1979
期刊：
影响因子：
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通讯作者：
J. Pedlosky
中科院分区：
文献类型：
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作者：
J. Pedlosky
摘要研究了具有连续切变和静力稳定度的大气中弱不稳定斜压扰动的有限振幅动力学。包括行星涡度梯度β、Ekman耗散和热阻尼的影响。多尺度分析表明，存在两个动力学制度。首先，在Ekman摩擦的影响下，在振荡接近平衡状态后实现准稳态。结果表明，在摩擦的影响下，纬向长波具有弱的不稳定性。其次，在埃克曼摩擦和热阻尼（最简单的牛顿冷却模型）的共同影响下，实现了真正的渐近状态。计算了振幅，当κ较小时，振幅与热阻尼κ无关。在稳态有限振幅状态下计算整流拍频通量。它与κ成比例。热通量与基本温度梯度和临界温度梯度之差成正比。
Abstract The finite-amplitude dynamics of a weakly unstable baroclinic disturbance in an atmosphere with continuous shear and static stability is investigated. The effects of β (the planetary vorticity gradient), Ekman dissipation and thermal damping are included. The multi-scale analysis demonstrates the existence of two-dynamical regimes. First, under the influence of Ekman friction quasi-steady states are achieved after an oscillatory approach to the equilibrium state. It is shown that under the influence of friction long zonal waves possess a weak instability. Second, under the joint influence of Ekman friction and thermal damping (of the simplest Newtonian cooling model) a true asymptotic state is achieved. The amplitude is calculated and is shown to be independent of the thermal damping κ when κ is small. The rectified beat flux is calculated in the steady finite amplitude state. It is proportional to κ. The beat flux is proportional to the difference between the basic temperature gradient and a cri...