Dynamics of Nonlinear Cross-Equatorial Flow. Part I: Potential Vorticity Transformation
Dynamics of Nonlinear Cross-Equatorial Flow. Part I: Potential Vorticity Transformation
复制标题
非线性越赤道流动力学。
DOI：
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发表时间：
1998
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：
C. Edwards;J. Pedlosky
摘要利用浅水模式研究了理想热带海洋中非线性西边界流中位涡的变化。在一个矩形域强迫的本地化，北方半球的质量源和一个分布式的汇，需要一个净，跨赤道的质量通量，一系列的数值实验研究如何位涡的变化，随着流体穿过赤道的迹象。耗散被包括为动量扩散，雷诺数被定义为每单位深度的质量源与粘度的比率，决定了流动的性质。当Re小于临界值（约30）时，流动是层流，可用线性理论很好地描述。当雷诺数刚好超过这个值时，系统变得与时间有关，在边界附近发展出一个符号的涡流，并稳定地传播穿过赤道。对于非常大的Re，出现了一个广泛而复杂的正异常和负异常网络。分析......
Abstract The transformation of potential vorticity within nonlinear deep western boundary currents in an idealized tropical ocean is studied using a shallow-water model. In a rectangular domain forced by a localized, Northern Hemisphere mass source and a distributed sink that require a net, cross-equatorial mass flux, a series of numerical experiments investigate how potential vorticity changes sign as fluid crosses the equator. Dissipation is included as momentum diffusion, and the Reynolds number, defined as the ratio of the mass source per unit depth to the viscosity, determines the nature of the flow. For Re less than a critical value (approximately 30) the flow is laminar and well described by linear theory. For Reynolds numbers just above this value, the system becomes time-dependent with eddies of one sign developing adjacent to the boundary and propagating steadily across the equator. For very large Re, an extensive and complicated network of both positive and negative anomalies emerges. Analysis ...