Comparing Ocean Surface Boundary Vertical Mixing Schemes Including Langmuir Turbulence
Comparing Ocean Surface Boundary Vertical Mixing Schemes Including Langmuir Turbulence
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DOI：
10.1029/2019ms001810
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发表时间：
2019-11
影响因子：
6.8
通讯作者：
Qing Li;B. Reichl;B. Fox‐Kemper;A. Adcroft;S. Belcher;G. Danabasoglu;A. Grant;S. Griffies;R. Hallberg;T. Hara;R. Harcourt;T. Kukulka;W. Large;J. McWilliams;Brodie C. Pearson;P. Sullivan;Luke P. van Roekel;Peng Wang;Zhihua Zheng
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文献类型：
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作者：
Qing Li;B. Reichl;B. Fox‐Kemper;A. Adcroft;S. Belcher;G. Danabasoglu;A. Grant;S. Griffies;R. Hallberg;T. Hara;R. Harcourt;T. Kukulka;W. Large;J. McWilliams;Brodie C. Pearson;P. Sullivan;Luke P. van Roekel;Peng Wang;Zhihua Zheng
六个最近的朗缪尔湍流参数化方案和五个传统的方案在一个共同的单柱建模框架中实现，并进行了一致的比较。这些方案在场景与匹配的大涡模拟中进行了测试，在地球仪上使用真实的强迫（JRA 55 ‐do，WAVEWATCH‐III模拟波浪）和初始条件（Argo），并在海洋系泊处观察到的真实条件下。传统的非朗缪尔方案系统性地低估了弱对流强迫下大涡模拟的垂直混合，而朗缪尔方案的精度不同。在全球范围内，现实的强迫朗缪尔方案产生的月平均混合层深度比非朗缪尔方案深6%（-1%至14%，90%置信度）或5.2 m（-0.2 m至17.4 m，90%置信度），在热带以外的地区，特别是南半球夏季的南大洋，差异最大。朗缪尔方案之间的差异很大（混合层深度标准差超过平均值的15%）：在波浪驱动湍流和稳定浮力强迫下最大，在强波浪驱动条件下其次是弱浮力强迫，在强对流强迫下一致。非朗缪尔方案在较小程度上彼此不一致，具有类似的排序。朗缪尔差异掩盖了在现实强迫下对朗缪尔效应量级的跨方案估计，突出了有限的理解和数值缺陷。提供了出现最大差异的地区和季节的地图，以指导进一步的研究和观察。
Six recent Langmuir turbulence parameterization schemes and five traditional schemes are implemented in a common single‐column modeling framework and consistently compared. These schemes are tested in scenarios versus matched large eddy simulations, across the globe with realistic forcing (JRA55‐do, WAVEWATCH‐III simulated waves) and initial conditions (Argo), and under realistic conditions as observed at ocean moorings. Traditional non‐Langmuir schemes systematically underpredict large eddy simulation vertical mixing under weak convective forcing, while Langmuir schemes vary in accuracy. Under global, realistic forcing Langmuir schemes produce 6% (−1% to 14% for 90% confidence) or 5.2 m (−0.2 m to 17.4 m for 90% confidence) deeper monthly mean mixed layer depths than their non‐Langmuir counterparts, with the greatest differences in extratropical regions, especially the Southern Ocean in austral summer. Discrepancies among Langmuir schemes are large (15% in mixed layer depth standard deviation over the mean): largest under wave‐driven turbulence with stabilizing buoyancy forcing, next largest under strongly wave‐driven conditions with weak buoyancy forcing, and agreeing during strong convective forcing. Non‐Langmuir schemes disagree with each other to a lesser extent, with a similar ordering. Langmuir discrepancies obscure a cross‐scheme estimate of the Langmuir effect magnitude under realistic forcing, highlighting limited understanding and numerical deficiencies. Maps of the regions and seasons where the greatest discrepancies occur are provided to guide further studies and observations.