An ocean large‐eddy simulation of Langmuir circulations and convection in the surface mixed layer
An ocean large‐eddy simulation of Langmuir circulations and convection in the surface mixed layer
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DOI：
10.1029/94jc03202
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发表时间：
1995-05
影响因子：
--
通讯作者：
E. Skyllingstad;D. Denbo
中科院分区：
文献类型：
--
作者：
E. Skyllingstad;D. Denbo
数值实验进行了使用三维大涡模拟模型的海洋表面混合层，其中包括Craik-Leibovich涡力参数化的表面波与平均电流的相互作用。实验结果表明，涡旋力产生的朗缪尔环流可以主导垂直混合。模拟的垂直速度场显示线性，小规模，相干结构的表面附近，延伸到整个模型域的顺风。在混合层的内部，运动的尺度增加到涡流的大小，大致相当于混合层的深度。与只有热通量和风应力的情况相比，有涡旋力的情况下有更强的近地面环流，特别是当热通量为正时。有和没有涡力，表面冷却和风应力的情况下，速度方差和湍流耗散率的计算表明，波流相互作用是一个占主导地位的混合过程中的上部混合层。热通量计算表明，在混合层底部的卷吸率可以高达两倍大时，涡力。在风应力减小的情况下，由于涡旋力与先前存在的惯性流相互作用，湍流耗散率在表面附近保持较高。在深混合层（{约}250米）的模拟表明，朗缪尔环流可以垂直输送水145米的条件下，表面加热。湍流耗散率和垂直温度结构的观测支持模式的结果。参考文献42篇，图20，21片。«少
Numerical experiments were performed using a three-dimensional large-eddy simulation model of the ocean surface mixed layer that includes the Craik-Leibovich vortex force to parameterize the interaction of surface waves with mean currents. Results from the experiments show that the vortex force generates Langmuir circulations that can dominate vertical mixing. The simulated vertical velocity fields show linear, small-scale, coherent structures near the surface that extend downwind across the model domain. In the interior of the mixed layer, scales of motion increase to eddy sizes that are roughly equivalent to the mixed-layer depth. Cases with the vortex force have stronger circulations near the surface in contrast to cases with only heat flux and wind stress, particularly when the heat flux is positive. Calculations of the velocity variance and turbulence dissipation rates for cases with and without the vortex force, surface cooling, and wind stress indicate that wave-current interactions are a dominant mixing process in the upper mixed layer. Heat flux calculations show that the entrainment rate at the mixed-layer base can be up to two times greater when the vortex force is included. In a case with reduced wind stress, turbulence dissipation rates remained high near the surface because of the vortexmore » force interaction with preexisting inertial currents. In deep mixed layers ({approximately}250 m) the simulations show that Langmuir circulations can vertically transport water 145 m during conditions of surface heating. Observations of turbulence dissipation rates and the vertical temperature structure support the model results. 42 refs., 20 figs., 21 tabs.« less