The KPP Boundary Layer Scheme for the Ocean: Revisiting Its Formulation and Benchmarking One‐Dimensional Simulations Relative to LES
The KPP Boundary Layer Scheme for the Ocean: Revisiting Its Formulation and Benchmarking One‐Dimensional Simulations Relative to LES
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海洋 KPP 边界层方案：重新审视其公式并针对 LES 进行一维模拟基准测试
DOI：
10.1029/2018ms001336
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发表时间：
2017
影响因子：
6.8
通讯作者：
M. Schmidt
中科院分区：
文献类型：
--
作者：
Luke P. van Roekel;A. Adcroft;G. Danabasoglu;S. Griffies;B. Kauffman;W. Large;M. Levy;B. Reichl;T. Ringler;M. Schmidt
我们评估了共同体海洋垂直混合项目版本的K廓线参数化(KPP)用于模拟上层海洋湍流混合。为此，我们将一维KPP模拟与水平平均大涡模拟(LESS)进行了比较，对比了一系列与海洋相关的区域。我们发现KPP的标准构型在许多强迫区域与LES是一致的，支持其物理基础。我们的评估还激励了在海洋环流模型中对KPP最佳做法的建议，并确定了需要进一步研究的领域。KPP的原始处理建议将内部扩散系数及其梯度与KPP在海洋表面边界层(OSBL)中计算的预测值相匹配。然而，我们发现，在表示OSBL底部附近快速变化的扩散系数的导数时的困难可能会导致模拟逼真度的损失。为了缓解这一困难，我们提出并评估了两种计算上更简单的方法：(1)仅与内部预测的扩散系数匹配和(2)在OSBL基处将KPP扩散系数设置为0。我们发现KPP卷吸浮力通量对垂直网格分辨率和如何诊断KPP边界层深度的细节很敏感。我们修改了KPP湍流切变速度参数化，以减少对分辨率的依赖。此外，对LES垂直湍流标量通量收支的检验表明，KPP参数的非局地示踪通量是不完全的，因为假设它只重新分配地面示踪通量。这一结果促进了非局地通量参数化的进一步研究。
We evaluate the Community ocean Vertical Mixing project version of the K‐profile parameterization (KPP) for modeling upper ocean turbulent mixing. For this purpose, one‐dimensional KPP simulations are compared across a suite of oceanographically relevant regimes against horizontally averaged large eddy simulations (LESs). We find the standard configuration of KPP consistent with LES across many forcing regimes, supporting its physical basis. Our evaluation also motivates recommendations for KPP best practices within ocean circulation models and identifies areas where further research is warranted. The original treatment of KPP recommends the matching of interior diffusivities and their gradients to the KPP‐predicted values computed in the ocean surface boundary layer (OSBL). However, we find that difficulties in representing derivatives of rapidly changing diffusivities near the base of the OSBL can lead to loss of simulation fidelity. To mitigate this difficulty, we propose and evaluate two computationally simpler approaches: (1) match to the internal predicted diffusivity alone and (2) set the KPP diffusivity to 0 at the OSBL base. We find the KPP entrainment buoyancy flux to be sensitive to vertical grid resolution and details of how to diagnose the KPP boundary layer depth. We modify the KPP turbulent shear velocity parameterization to reduce resolution dependence. Additionally, an examination of LES vertical turbulent scalar flux budgets shows that the KPP‐parameterized nonlocal tracer flux is incomplete due to the assumption that it solely redistributes the surface tracer flux. This result motivates further studies of the nonlocal flux parameterization.
在秋季风暴期间，高能次中尺度保持强烈的混合层分层
影响因子：
3.5
作者：
Whitt, Daniel B.;Taylor, John R.
通讯作者：
Taylor, John R.