Estimating wave effects on vertical mixing is a necessary step toward improving the accuracy and reliability of upper-ocean forecasts. In this study, we evaluate the wave effects on upper-ocean mixing in the northern East China Sea in summer by analyzing the results of comparative experiments: a stand-alone ocean model as a control run and two ocean–wave coupled models that include the effect of the breaking waves (BW) and of the wave–current interaction (WCI) with a vortex-force formalism. The comparison exhibits that under weak wind conditions, the BW effect prescribed by wave dissipation energy significantly enhances near-surface mixing because of increased downward turbulent kinetic energy (TKE), whereas the WCI has little effect on vertical mixing. Increased TKE results in a mixed-layer depth deepened by ~46% relative to the control run, which provides better agreement with the observed surface thermal structure. An additional experiment with local wind–based BW parameterization confirms the importance of nonlocally generated waves that propagated into the study area upon near-surface mixing. This suggests that under calm wind conditions, waves propagated over distances can largely affect surface vertical mixing; thus, ocean–wave coupling is capable of improving the surface thermal structure.

中文翻译：

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风浪条件下海浪耦合系统中碎波对近地表混合的影响

估计波浪对垂直混合的影响是提高上层海洋预报准确性和可靠性的必要步骤。在这项研究中，我们通过分析比较实验的结果，评估夏季东海北部海浪对上层海洋混合的影响：一个独立的海洋模型作为控制运行，以及两个海浪耦合模型，其中包括波浪力形式主义对破碎波（BW）和波流相互作用（WCI）的影响。比较表明，在弱风条件下，由于增加的向下湍动能（TKE），波耗散能量规定的BW效应显着增强了近地表混合，而WCI对垂直混合的影响很小。TKE的增加导致混合层深度相对于对照运行加深约46％，与观察到的表面热结构更好地吻合。另一个基于局部风的BW参数化的实验证实了在近地表混合后非局部产生的波传播到研究区域的重要性。这表明在风平稳的情况下，在远处传播的波会极大地影响地面垂直混合。因此，海浪耦合能够改善表面热结构。