Thermohaline‐Shear Instability
Thermohaline‐Shear Instability
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DOI：
10.1029/2018gl081009
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发表时间：
2019-01
影响因子：
5.2
通讯作者：
T. Radko
中科院分区：
文献类型：
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作者：
T. Radko
这项研究提出了热盐剪切不稳定性的线性理论，这是实现在海洋流动的动力学和扩散稳定。该框架是基于无界Couette模型，这使得它可以解耦的空间均匀剪切不稳定性的影响所造成的速度分布的拐点的存在下的不稳定性。基本状态被假设为与时间相关，这反映了内波在控制细尺度剪切中的作用。线性稳定性分析表明，在大多数温度和盐度同时向下增加的海洋区域，满足温盐剪切不稳定的条件。我们的结论是，温盐剪切不稳定性代表了一个合理的机制，主动扩散对流的启动，这反过来又是必不可少的温盐楼梯的形成和维持双扩散交错。
This study presents the linear theory of thermohaline‐shear instability, which is realized in oceanic flows that are dynamically and diffusively stable. The framework is based on the unbounded Couette model, which makes it possible to decouple the destabilizing effects of spatially uniform shear from instabilities caused by the presence of inflection points in velocity profiles. The basic state is assumed to be time dependent, which reflects the role of internal waves in controlling fine‐scale shear. Linear stability analysis suggests that conditions for thermohaline‐shear instability are met in most ocean regions where temperature and salinity concurrently increase downward. We conclude that thermohaline‐shear instability represents a plausible mechanism for the initiation of active diffusive convection, which, in turn, is essential for the formation of thermohaline staircases and maintenance of double‐diffusive interleaving.