Anisotropic material transport by eddies and eddy-driven currents in a model of the North Atlantic
Anisotropic material transport by eddies and eddy-driven currents in a model of the North Atlantic
复制标题
北大西洋模型中涡流和涡流驱动流的各向异性物质传输
DOI：
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发表时间：
2009
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：
I. Kamenkovich;P. Berloff;J. Pedlosky
摘要：本研究通过拉格朗日粒子轨迹分析，分析了北大西洋大气环流模型中涡流和涡流驱动的纬向射流物质传输的各向异性特性。纬向方向的扩散速率（此处定义为粒子分散变化速率的一半）系统地超过经向速率一个数量级。上层海洋纬向和经向扩散率的面积平均值分别约为 8100 和 1400 m2 s−1，而在深海则分别为 2400 和 200 m2 s−1。结果表明，这种各向异性主要是由于瞬态涡流的作用，而不是与时均射流相关的剪切色散。这一特性与本研究中的涡流具有纬向拉长形状的事实相一致。除了上层海洋副极地环流外，涡流还会引起超扩散纬向扩散，垂直方向上扩散速率的显着变化......
Abstract This study analyzes anisotropic properties of the material transport by eddies and eddy-driven zonal jets in a general circulation model of the North Atlantic through the analysis of Lagrangian particle trajectories. Spreading rates—defined here as half the rate of change in the particle dispersion—in the zonal direction systematically exceed the meridional rates by an order of magnitude. Area-averaged values for the upper-ocean zonal and meridional spreading rates are approximately 8100 and 1400 m2 s−1, respectively, and in the deep ocean they are 2400 and 200 m2 s−1. The results demonstrate that this anisotropy is mainly due to the action of the transient eddies and not to the shear dispersion associated with the time-mean jets. This property is consistent with the fact that eddies in this study have zonally elongated shapes. With the exception of the upper-ocean subpolar gyre, eddies also cause the superdiffusive zonal spreading, significant variations in the spreading rate in the vertical and...