Effect of horizontal divergence on the geostrophic turbulence on a beta-plane: Suppression of the Rhines effect
Effect of horizontal divergence on the geostrophic turbulence on a beta-plane: Suppression of the Rhines effect
复制标题
水平散度对 β 平面上地转湍流的影响：莱茵河效应的抑制
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
A. Masuda
中科院分区：
文献类型：
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作者：
A. Okuno;A. Masuda
本文研究了强层结或水平辐散对β平面上几乎自由衰减的地转湍流的影响。在模式海洋中，假设表层在平静的深层之上是活跃的，因此先验地禁止正压作用，以净化水平辐散的影响。通过调整来保持动能恒定以对抗水平发散的延缓效应，从而在数值上加速了光谱演化。首先，对水平散度较小或中等的情况进行了数值实验，作为对比；UF/β<；O(1)，其中U是湍流的特征速度，F是变形半径的平方反比。正如已经反复报道的那样，β效应诱导了一个以带状电流为特征的高度各向异性的场。还证实了在高波数k时，动能具有与k−5近似成正比的一维谱，水平散度增大。
An investigation is made on the effect of strong stratification, or horizontal divergence, on almost freely decaying geostrophic turbulence on a β-plane. In a model ocean, the surface layer is assumed to be active above the quiet deep layer, so that barotropification is prohibited a priori to purify the effect of horizontal divergence. Spectral evolution is accelerated numerically by an adjustment to keep kinetic energy constant against the retarding effect of horizontal divergence. First, numerical experiment is carried out for small or moderate horizontal divergence as control runs for comparison; UF/β<O(1), where U is the characteristic velocity of turbulence and F the squared inverse of the radius of deformation. As has been reported repeatedly, the β-effect induces a highly anisotropic field characterized by a band of zonal currents. It is confirmed also that kinetic energy has a one-dimensional spectrum approximately proportional to k−5 at high wave numbers k. Then, horizontal divergence is enlarged...