Langmuir Turbulence in Swell

McWilliams, James C.; Huckle, Edward; Liang, Jun‐Hong; Sullivan, Peter P.

doi:10.1175/jpo-d-13-0122.1

Cited by 72 publications

(91 citation statements)

References 27 publications

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“…Recently, several studies (McWilliams and Sullivan 2000;Smyth et al 2002;McWilliams et al 2012McWilliams et al , 2014Sinha et al 2015) proposed modifications to the KPP model that include the Langmuir turbulence.…”

Section: Geophysical Turbulence Closure Modelsmentioning

confidence: 99%

“…In McWilliams and Sullivan (2000), the Langmuir turbulence is included via an enhancement factor to the eddy viscosity (and diffusivity) through an enhanced turbulent velocity scale. The enhancement factor is parameterized from the turbulent Langmuir number:…”

Section: Geophysical Turbulence Closure Modelsmentioning

confidence: 99%

“…In the high Reynolds number planetary boundary layer turbulence, the Langmuir turbulence (turbulence that is modified by the CL vortex force) exists over scales ranging from O(1) m to the mixed layer depth, even when not organized as coherent Langmuir circulations (McWilliams et al 1997). Langmuir turbulence has been extensively studied for the last two decades using large-eddy simulation (LES) models that can resolve explicitly the dominant scales of Langmuir turbulence (Skyllingstad and Denbo 1995;McWilliams et al 1997;Skyllingstad et al 2000;Noh et al 2004;Min and Noh 2004;Polton and Belcher 2007;Sullivan et al 2007;Harcourt and D'Asaro 2008;Grant and Belcher 2009;Kukulka et al 2009;Teixeira and Belcher 2010;Kukulka et al 2010;Noh et al 2011;Van Roekel et al 2012). All support the conclusion that the CL vortex force strengthens upper-ocean mixing in many different regimes.…”

Section: Introductionmentioning

confidence: 98%

“…LES has also been used to study stochastic momentum injection via wave breaking in the presence of Langmuir turbulence in the planetary boundary layer Sullivan et al 2007;McWilliams et al 2012). These studies show that the impact of intermittent breaking momentum injection is mostly limited to the upper several meters when compared to constant surface momentum fluxes.…”

Section: Introductionmentioning

confidence: 99%

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Langmuir Turbulence Parameterization in Tropical Cyclone Conditions

Reichl

Wei

Hara

et al. 2016

Journal of Physical Oceanography

103

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The Stokes drift of surface waves significantly modifies the upper-ocean turbulence because of the CraikLeibovich vortex force (Langmuir turbulence). Under tropical cyclones the contribution of the surface waves varies significantly depending on complex wind and wave conditions. Therefore, turbulence closure models used in ocean models need to explicitly include the sea state-dependent impacts of the Langmuir turbulence. In this study, the K-profile parameterization (KPP) first-moment turbulence closure model is modified to include the explicit Langmuir turbulence effect, and its performance is tested against equivalent large-eddy simulation (LES) experiments under tropical cyclone conditions. First, the KPP model is retuned to reproduce LES results without Langmuir turbulence to eliminate implicit Langmuir turbulence effects included in the standard KPP model. Next, the Lagrangian currents are used in place of the Eulerian currents in the KPP equations that calculate the bulk Richardson number and the vertical turbulent momentum flux. Finally, an enhancement to the turbulent mixing is introduced as a function of the nondimensional turbulent Langmuir number. The retuned KPP, with the Lagrangian currents replacing the Eulerian currents and the turbulent mixing enhanced, significantly improves prediction of upper-ocean temperature and currents compared to the standard (unmodified) KPP model under tropical cyclones and shows improvements over the standard KPP at constant moderate winds (10 m s 21 ).

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Section: Geophysical Turbulence Closure Modelsmentioning

confidence: 99%

Section: Geophysical Turbulence Closure Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Langmuir Turbulence Parameterization in Tropical Cyclone Conditions

Reichl

Wei

Hara

et al. 2016

Journal of Physical Oceanography

103

View full text Add to dashboard Cite

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“…For remotely generated (i.e., swell) waves, even smaller La t values (reaching 0.1-0.2) may be realized. 33,34 Motivated by the observed anisotropy of LC and the common occurrence of relatively small values of La t , Chini et al 26 derived an asymptotically reduced version of the CL equations by exploiting the formal limit La t → 0. Inspection of Eq.…”

Section: Reduced Craik-leibovich (Rcl) Equationsmentioning

confidence: 99%

Dynamic patterns in the reduced Craik–Leibovich equations

et al. 2015

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Numerical simulations of an asymptotically reduced version of the Craik–Leibovich (CL) equations are described. By filtering surface waves, the CL equations facilitate simulations of surface-wave driven or surface-wave modified phenomena in the upper ocean—most notably, Langmuir circulation (LC)—with time scales long relative to the period of the dominant waves. Although numerical simulations of the fully three-dimensional CL equations are now routine, simulations in spatially extended domains, hundreds of times the characteristic width of individual LC vortices, require immense computing resources. The reduced CL (rCL) equations render numerical simulations in very long domains more feasible by exploiting the strongly anisotropic structure of LC that emerges in the strong CL “vortex force” limit. Here, simulations of the rCL equations are performed to explore the dynamics admitted by the reduced system. Spatially quasi-coherent, three-dimensional flow structures that drift downwind are found to be a prominent feature of the reduced dynamics in the parameter regime explored. The spatial form and temporal variability of these structures are associated with a resonance between pairs of LC vortices with cross-wind (transverse) wavenumbers in a 2:1 ratio. Depending upon the strength of the wind and surface-wave forcing, this spatial resonance leads to either periodic or aperiodic temporal oscillations in the number of LC vortices crossing a fixed downwind station, a process that is accompanied by the formation of Y-shaped features in Lagrangian surface patterns. The stems of these “Y-junctions” are preferentially oriented downwind, as is commonly reported in field observations of LC.

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Oil plumes and dispersion in Langmuir, upper-ocean turbulence: Large-eddy simulations and K-profile parameterization

Yang

Chen

Chamecki

et al. 2015

J. Geophys. Res. Oceans

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Once oil plumes such as those originating from underwater blowouts reach the ocean mixed layer (OML), their near-surface dispersion is influenced heavily by wind and wave-generated Langmuir turbulence. In this study, the complex oil spill dispersion process is modeled using large-eddy simulation (LES). The mean plume dispersion is characterized by performing statistical analysis of the resulting fields from the LES data. Although the instantaneous oil concentration exhibits high intermittency with complex spatial patterns such as Langmuir-induced striations, it is found that the time-averaged oil distribution can still be described quite well by smooth Gaussian-type plumes. LES results show that the competition between droplet rise velocity and vertical turbulent diffusion due to Langmuir turbulence is crucial in determining both the dilution rate and overall direction of transport of oil plumes in the OML. The smoothness of the mean plume makes it feasible to aim at modeling the oil dispersion using Reynolds-averaged type formulations, such as the K-profile parameterization (KPP) with sufficient vertical resolution to capture vertical profiles in the OML. Using LES data, we evaluate the eddy viscosity and eddy diffusivity following the KPP framework. We assess the performance of previous KPP models for pure shear turbulence and Langmuir turbulence by comparing them with the LES data. Based on the assessment a modified KPP model is proposed, which shows improved overall agreement with the LES results for both the eddy viscosity and the eddy diffusivity of the oil dispersion under a variety of flow conditions and droplet sizes.

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Langmuir Turbulence in Swell

Cited by 72 publications

References 27 publications

Langmuir Turbulence Parameterization in Tropical Cyclone Conditions

Langmuir Turbulence Parameterization in Tropical Cyclone Conditions

Dynamic patterns in the reduced Craik–Leibovich equations

Oil plumes and dispersion in Langmuir, upper-ocean turbulence: Large-eddy simulations and K-profile parameterization

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