Comparing Ocean Boundary Vertical Mixing Schemes with Langmuir Turbulence
Abstract
Langmuir turbulence is an important physical process that affects the turbulent mixing in the ocean surface boundary layer (OSBL) and requires parameterization in a climate model. Various approaches to include the effects of Langmuir turbulence in an OSBL vertical mixing scheme have been proposed in the literature, including developments and modifications based on the bulk layer model, the K-Profile Parameterization (KPP), and the two-equation models. These proposed vertical mixing schemes with Langmuir turbulence effects each have been implemented and tested against Large Eddy Simulations (LES) or observations individually. Seldom have they been compared with each other side by side. It is therefore unclear yet to what extent do these different vertical mixing schemes with Langmuir turbulence agree or disagree. Motivated by such uncertainties, this study compares the different OSBL vertical mixing schemes with Langmuir turbulence in a common framework. In particular, one-dimensional column model simulations of the OSBL at different regions over the global ocean (one for each 4-degree by 4-degree box) are conducted using each of the vertical mixing schemes with Langmuir turbulence. These simulations are initialized from Argo temperature and salinity profiles and force by realistic surface wind, waves and buoyancy forcing. The interannually varying air-sea flux datasets from the Coordinated Ocean-ice Reference Experiments phase II (CORE-II) are used to provide the regional wind and buoyancy forcing, and surface wave information is obtained from a WaveWatch III simulation forced by the same CORE-II forcing. Regimes where there is disagreement between these OSBL schemes are identified and sorted by locations, seasons and dimensionless parameters. Such disagreements highlight gaps in our understanding of the OSBL physics where either more LES studies or more ocean observations are needed. This information is therefore valuable for both ocean modelers and observationalists.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMOS31B..06L
- Keywords:
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- 3307 Boundary layer processes;
- ATMOSPHERIC PROCESSESDE: 4504 Air/sea interactions;
- OCEANOGRAPHY: PHYSICALDE: 4560 Surface waves and tides;
- OCEANOGRAPHY: PHYSICALDE: 4572 Upper ocean and mixed layer processes;
- OCEANOGRAPHY: PHYSICAL