North Atlantic Barotropic Vorticity Balances in Numerical Models
North Atlantic Barotropic Vorticity Balances in Numerical Models
复制标题
数值模型中的北大西洋正压涡度平衡
DOI：
10.1175/jpo-d-15-0133.1
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发表时间：
2016
影响因子：
3.5
通讯作者：
S. Yeager
中科院分区：
文献类型：
--
作者：
J. Schoonover;W. Dewar;N. Wienders;J. Gula;J. McWilliams;M. Molemaker;S. Bates;G. Danabasoglu;S. Yeager
摘要以北大西洋为重点，在不同的模式平台和分辨率下进行了数值模拟。正压涡度诊断证实，副热带环流的特征主要是在施加的风应力旋度和底压扭矩之间的无粘性平衡。在墨西哥湾流的区域综合预算中，向北回流由底部压力扭矩平衡。这些综合预算在模型平台和分辨率上是一致的，表明这些平衡是稳健的。在100公里和10公里分辨率下的两个模拟，产生了一个更偏北的分离湾流，但得到了正确的综合涡度平衡。在这些模拟中，粘性扭矩在较小的尺度上是不可忽略的，表明分离与局部动力学的细节有关。这些结果与尺度分析的论点相一致，该论点表明，双调和粘性扭矩尤其会破坏非粘性扭矩。
AbstractNumerical simulations are conducted across model platforms and resolutions with a focus on the North Atlantic. Barotropic vorticity diagnostics confirm that the subtropical gyre is characterized by an inviscid balance primarily between the applied wind stress curl and bottom pressure torque. In an area-integrated budget over the Gulf Stream, the northward return flow is balanced by bottom pressure torque. These integrated budgets are shown to be consistent across model platforms and resolution, suggesting that these balances are robust. Two of the simulations, at 100- and 10-km resolutions, produce a more northerly separating Gulf Stream but obtain the correct integrated vorticity balances. In these simulations, viscous torque is nonnegligible on smaller scales, indicating that the separation is linked to the details of the local dynamics. These results are shown to be consistent with a scale analysis argument that suggests that the biharmonic viscous torque in particular is upsetting the inviscid...