Numerical Simulations of the Equilibrium between Eddy-Induced Restratification and Vertical Mixing
Numerical Simulations of the Equilibrium between Eddy-Induced Restratification and Vertical Mixing
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DOI：
10.1175/jpo-d-15-0110.1
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发表时间：
2016-02
影响因子：
3.5
通讯作者：
S. Bachman;John R. Taylor
中科院分区：
文献类型：
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作者：
S. Bachman;John R. Taylor
摘要亚中尺度动力学通过亚中尺度涡旋和地面强迫的相互作用，在混合层的层结中起主导作用。以往对这种相互作用的研究主要集中在亚中尺度湍流的时间演化特征上，如斜压不稳定锋的旋转下降。本文着重于海洋混合层的平衡动力学，强迫和耗散是平衡的，通过尺度分析和数值模拟相结合。定常动力学很好地描述了湍流热风平衡，外部强迫参数化的强垂直扩散系数κ。标度律的特征垂直长度尺度L，非地转速度尺度U和V，浮力频率N2，和涡浮力通量，这是适当的湍流混合层的分层是平衡对强垂直混合。一套数字…
AbstractSubmesoscale dynamics are hypothesized to play a leading-order role in setting the stratification of the mixed layer via the interaction of submesoscale eddies and surface forcing. Previous studies of such interactions have generally focused on the time-evolving characteristics of submesoscale turbulence, such as the spindown of a baroclinically unstable front. This paper focuses instead on the equilibrium dynamics of the oceanic mixed layer, where forcing and dissipation are in balance, through a combination of scaling analysis and numerical simulations. The steady dynamics are well described by a turbulent thermal wind balance, with external forcing parameterized by a strong vertical diffusivity κ. Scaling laws are developed for the characteristic vertical length scale Lυ, ageostrophic velocity scales U and V, buoyancy frequency N2, and eddy buoyancy flux , which are appropriate for a turbulent mixed layer whose stratification is equilibrated against strong vertical mixing. A suite of numerical ...