A generalized marginal stability criterion for shear-induced ocean interior diapycnal turbulent mixing
A generalized marginal stability criterion for shear-induced ocean interior diapycnal turbulent mixing
复制标题
剪切引起的海洋内部二重湍流混合的广义边际稳定性判据
DOI：
10.1002/essoar.10507781.1
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Mashayek A
中科院分区：
文献类型：
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作者：
Mashayek A
内波破碎引起的湍流混合是海洋环流和全球示踪剂收支的关键。虽然经典的边缘剪切不稳定性的理查森数为1/4已被认为是潜在的相关湍流波破碎，其相关性的能量区的潮汐，风和浮力梯度激发非线性相互作用的过程一直被怀疑。我们发现，剪切不稳定性确实是相关的海洋内部，并提出了一种替代的广义边缘稳定性标准，根据Ozmidov和索普湍流尺度的比例，这不仅适用于海洋内部，但仍然相关的湍流边界层。这使得准确的量化的过渡，从下降流上升流区在最近出现的海洋环流的范例。我们的研究结果有助于气候模式更准确地计算混合驱动的深海环流和海洋内部示踪剂的通量。
Turbulent mixing induced by breaking internal waves is key to the ocean circulation and global tracer budgets. While the classic marginal shear instability of Richardson number ∼ 1/4 has been considered as potentially relevant to turbulence wave breaking, its relevance to energetic zones where tides, winds, and buoyancy gradients excite non-linearly interacting processes has been suspect. We show that shear instability is indeed relevant in the ocean interior and propose an alternative generalized marginal stability criterion, based on the ratio of Ozmidov and Thorpe turbulence scales, which not only applies to the ocean interior, but remains relevant within turbulent boundary layers. This allows for accurate quantification of the transition from downwelling to upwelling zones in a recently emerged paradigm of ocean circulation. Our results help climate models more accurately calculate the mixing-driven deep ocean circulation and fluxes of tracers in the ocean interior.