Mixing driven by critical reflection of near-inertial waves over the Texas-Louisiana shelf
Mixing driven by critical reflection of near-inertial waves over the Texas-Louisiana shelf
复制标题
德克萨斯州-路易斯安那陆架上近惯性波的临界反射驱动的混合
DOI：
10.1175/jpo-d-22-0004.1
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发表时间：
2022
影响因子：
3.5
通讯作者：
Kobashi, Daijiro
中科院分区：
文献类型：
--
作者：
Qu, Lixin;Thomas, Leif N.;Hetland, Robert D.;Kobashi, Daijiro
内波驱动的混合在沿海海洋的研究一直集中在内潮汐，而风驱动的近惯性波（NIWs）在这方面得到的关注较少。这项研究表明，在得克萨斯州-路易斯安那州大陆架的NIW驱动的混合的情况。在高分辨率模拟的支持下，陆海空风驱动的近红外线辐射向下在一个尖锐的锋，并加强混合的底部边界层的近红外线集中，因为倾斜的临界反射。在平均气流处于热成风平衡且仅沿坡法线方向变化的假设下，近红外线倾斜临界反射的判据为（其中ω为波频，sbo为底坡，ρ为等密坡）。在理想化的模拟中探索了驱动增强混合的机制。在倾斜的临界反射，近红外线放大增强剪切和周期性destratitify底部边界层通过差分浮力平流，导致周期性增强混合。示踪剂的湍流运输也增强了NIWs的倾斜临界反射，这对德克萨斯州-路易斯安那州大陆架的底部缺氧有影响。
Studies of internal wave-driven mixing in the coastal ocean have been focused on internal tides, while wind-driven near-inertial waves (NIWs) have received less attention in this regard. This study demonstrates a scenario of NIW-driven mixing over the Texas–Louisiana shelf. Supported by a high-resolution simulation over the shelf, the NIWs driven by land–sea breeze radiate downward at a sharp front and enhance the mixing in the bottom boundary layer where the NIWs are focused because of slantwise critical reflection. The criterion for slantwise critical reflection of NIWs is(whereωis the wave frequency,sbotis the bottom slope, andsρis the isopycnal slope), under the assumption that the mean flow is in a thermal wind balance and only varies in the slope-normal direction. The mechanism driving the enhanced mixing is explored in an idealized simulation. During slantwise critical reflection, NIWs are amplified with enhanced shear and periodically destratify a bottom boundary layer via differential buoyancy advection, leading to periodically enhanced mixing. Turbulent transport of tracers is also enhanced during slantwise critical reflection of NIWs, which has implications for bottom hypoxia over the Texas–Louisiana shelf.