Vertical mixing schemes in the coastal ocean: Comparison of the level 2.5 Mellor‐Yamada scheme with an enhanced version of the K profile parameterization

Durski, S. M.

doi:10.1029/2002jc001702

Cited by 129 publications

(76 citation statements)

References 25 publications

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“…MY performed similar to NN and better than GLS when the simulations were stable and completed. LMD mixed too much, which was also found for weak stratification by Durski et al (2004). They also found that MY mixed more than LMD in strong stratification and less in weak stratification.…”

Section: Discussionmentioning

confidence: 79%

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Surface wind mixing in the Regional Ocean Modeling System (ROMS)

Robertson

Hartlipp

2017

Geosci. Lett.

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Mixing at the ocean surface is key for atmosphere-ocean interactions and the distribution of heat, energy, and gases in the upper ocean. Winds are the primary force for surface mixing. To properly simulate upper ocean dynamics and the flux of these quantities within the upper ocean, models must reproduce mixing in the upper ocean. To evaluate the performance of the Regional Ocean Modeling System (ROMS) in replicating the surface mixing, the results of four different vertical mixing parameterizations were compared against observations, using the surface mixed layer depth, the temperature fields, and observed diffusivities for comparisons. The vertical mixing parameterizations investigated were Mellor-Yamada 2.5 level turbulent closure (MY), Large-McWilliams-Doney Kpp (LMD), Nakanishi-Niino (NN), and the generic length scale (GLS) schemes. This was done for one temperate site in deep water in the Eastern Pacific and three shallow water sites in the Baltic Sea. The model reproduced the surface mixed layer depth reasonably well for all sites; however, the temperature fields were reproduced well for the deep site, but not for the shallow Baltic Sea sites. In the Baltic Sea, the models overmixed the water column after a few days. Vertical temperature diffusivities were higher than those observed and did not show the temporal fluctuations present in the observations. The best performance was by NN and MY; however, MY became unstable in two of the shallow simulations with high winds. The performance of GLS nearly as good as NN and MY. LMD had the poorest performance as it generated temperature diffusivities that were too high and induced too much mixing. Further observational comparisons are needed to evaluate the effects of different stratification and wind conditions and the limitations on the vertical mixing parameterizations.

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Section: Discussionmentioning

confidence: 79%

“…Although Durski et al (2004) investigated the performance of MY and LMD in ROMS, a comparison was not made of the performance of the new GLS scheme. Burchard and Bolding (2001) investigated several flavors of GLS, but not specifically for ROMS.…”

Section: Introductionmentioning

confidence: 99%

Surface wind mixing in the Regional Ocean Modeling System (ROMS)

Robertson

Hartlipp

2017

Geosci. Lett.

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“…Although this parametrisation is widely used in coastal ocean application, it should be noted that the choice of turbulence closure scheme can have an impact on resulting circulation, especially in areas close to the shore. However, this impact seems negligible in the bottom layer of the sea (Durski et al 2004). On the whole, the physical assumptions made in this approach seem reasonable for the studied area and rather do not induce significant errors of modelled quantities.…”

Section: Uncertainties In Modellingmentioning

confidence: 99%

Extreme bottom velocities induced by wind wave and currents in the Gulf of Gdańsk

et al. 2017

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The principal goal of this study is to get some preliminary insights about the intensity of water movement generated by wind waves, and due to the currents in the bottom waters of Gulf of Gdańsk, during severe storms. The Gulf of Gdańsk is located in the southern Baltic Sea. This paper presents the results of analysis of wave and current-induced velocities during extreme wind conditions, which are determined based on long-term historical records. The bottom velocity fields originated from wind wave and wind currents, during analysed extreme wind events, are computed independently of each other. The long-term wind wave parameters for the Baltic Sea region are derived from the 44-year hindcast wave database generated in the framework of the project HIPOCAS funded by the European Union. The output from the numerical wave model WAM provides the boundary conditions for the model SWAN operating in high-resolution grid covering the area of the Gulf of Gdańsk. Wind current velocities are calculated with the M3D hydrodynamic model developed in the Institute of Oceanography of the University of Gdańsk based on the POM model. The three dimensional current fields together with trajectories of particle tracers spreading out of bottom boundary layer are modelled, and the calculated fields of bottom velocities are presented in the form of 2D maps. During northerly winds, causing in the Gulf of Gdańsk extreme waves and most significant wind-driven circulation, the wave-induced bottom velocities are greater than velocities due to currents. The current velocities in the bottom layer appeared to be smaller by an order of magnitude than the wave-induced bottom orbital velocities. Namely, during most severe northerly storms analysed, current bottom velocities ranged about 0.1-0.15 m/s, while the root mean square of wave-induced near-seabed velocities reached maximum values of up to 1.4 m/s in the southern part of Gulf of Gdańsk.

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“…Modeling tools, with appropriate horizontal and vertical discretization, are needed (finite difference -finite volumes -finite elements; structured -unstructured grids). Also the choice in numerical parameterization schemes, particularly concerning vertical mixing, play a central role (Durski et al, 2004).…”

Section: W J Mckiver Et Al: Vertical Hydrodynamic Coastal Processesmentioning

confidence: 99%

Investigation of model capability in capturing vertical hydrodynamic coastal processes: a case study in the north Adriatic Sea

et al. 2016

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Abstract. In this work we consider a numerical study of hydrodynamics in the coastal zone using two different models, SHYFEM (shallow water hydrodynamic finite element model) and MITgcm (Massachusetts Institute of Technology general circulation model), to assess their capability to capture the main processes. We focus on the north Adriatic Sea during a strong dense water event that occurred at the beginning of 2012. This serves as an interesting test case to examine both the models strengths and weaknesses, while giving an opportunity to understand how these events affect coastal processes, like upwelling and downwelling, and how they interact with estuarine dynamics. Using the models we examine the impact of setup, surface and lateral boundary treatment, resolution and mixing schemes, as well as assessing the importance of nonhydrostatic dynamics in coastal processes. Both models are able to capture the dense water event, though each displays biases in different regions. The models show large differences in the reproduction of surface patterns, identifying the choice of suitable bulk formulas as a central point for the correct simulation of the thermohaline structure of the coastal zone. Moreover, the different approaches in treating lateral freshwater sources affect the vertical coastal stratification. The results indicate the importance of having high horizontal resolution in the coastal zone, specifically in close proximity to river inputs, in order to reproduce the effect of the complex coastal morphology on the hydrodynamics. A lower resolution offshore is acceptable for the reproduction of the dense water event, even if specific vortical structures are missed. Finally, it is found that nonhydrostatic processes are of little importance for the reproduction of dense water formation in the shelf of the north Adriatic Sea.

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Vertical mixing schemes in the coastal ocean: Comparison of the level 2.5 Mellor‐Yamada scheme with an enhanced version of the K profile parameterization

Cited by 129 publications

References 25 publications

Surface wind mixing in the Regional Ocean Modeling System (ROMS)

Surface wind mixing in the Regional Ocean Modeling System (ROMS)

Extreme bottom velocities induced by wind wave and currents in the Gulf of Gdańsk

Investigation of model capability in capturing vertical hydrodynamic coastal processes: a case study in the north Adriatic Sea

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