State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
Sci Rep. 2018 Jul 6;8(1):10281. doi: 10.1038/s41598-018-28554-z.
Fine-scale parameterizations based on shear and stratification are widely used to study the intensity and spatial distribution of turbulent diapycnal mixing in the ocean. Two well-known fine-scale parameterizations, Gregg-Henyey-Polzin (GHP) parameterization and MacKinnon-Gregg (MG) parameterization, are assessed with the full-depth microstructure data obtained in the North Pacific. The GHP parameterization commonly used in the open ocean succeeds in reproducing the dissipation rates over smooth topography but fails to predict the turbulence over rough topography. Failure of GHP parameterization over rough topography is attributed to the deviation of internal wave spectrum from the Garrett-Munk (GM) spectrum. The internal wave field over rough topography is characterized by energetic intermediate-scale and small-scale internal waves that are not described well by the GM model. The MG parameterization that is widely used in coastal environments is found to be successful in reproducing the dissipation rates over both smooth and rough topographies. The efficacy of GHP and MG parameterizations in evaluating the dissipation rates has been assessed. The result indicates that MG parameterization predicts the magnitude and variability of the dissipation rates better than the GHP parameterization.
基于切变和分层的精细参数化广泛用于研究海洋中湍流垂向混合的强度和空间分布。两种著名的精细参数化，Gregg-Henyey-Polzin（GHP）参数化和 MacKinnon-Gregg（MG）参数化，利用在北太平洋获得的全深度微观结构数据进行了评估。GHP 参数化常用于开阔海域，在平滑地形上成功再现了耗散率，但在粗糙地形上却无法预测湍流。GHP 参数化在粗糙地形上的失效归因于内波谱与 Garrett-Munk（GM）谱的偏差。粗糙地形上的内波场以高能中等尺度和小尺度内波为特征，GM 模型无法很好地描述这些内波。MG 参数化广泛用于沿海环境，在平滑和粗糙地形上都能成功再现耗散率。评估了 GHP 和 MG 参数化在评估耗散率方面的效果。结果表明，MG 参数化比 GHP 参数化更能准确预测耗散率的大小和变化。
