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James C. McWilliams, Edward Huckle, Junhong Liang, and Peter P. Sullivan

1. Introduction The wind blows and the waves rise and roll on. This is the regime of Langmuir turbulence in the oceanic surface boundary layer (BL), so-called because Langmuir circulations (often recognized by the windrows in the surfactants they cause) are the primary turbulent eddies whose vertical momentum and buoyancy fluxes maintain the mean ageostrophic current and density stratification. Langmuir circulations arise from the instability of wind-driven boundary layer shear in the presence

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R-C. Lien, B. Sanford, and W-T. Tsai

1. Introduction In the oceanic surface mixed layer, primary turbulent processes include wind-driven shear turbulence, convective turbulence, surface wave breaking, and Langmuir circulation (LC). Previous results provide reliable wind-driven shear and convective turbulence scalings ( Shay and Gregg 1986 ; Lombardo and Gregg 1989 ). Recent studies report progress on the parameterization of turbulence mixing due to surface wave breaking ( Terray et al. 1996 ; Drennan et al. 1996 ; Anis and Moum

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Øyvind Breivik, Ana Carrasco, Joanna Staneva, Arno Behrens, Alvaro Semedo, Jean-Raymond Bidlot, and Ole Johan Aarnes

-ocean circulation through generation of Langmuir turbulence (e.g., Belcher et al. 2012 ; D’Asaro et al. 2014 ; Fan and Griffies 2014 ; Li et al. 2016 , 2017 ) as well as the Coriolis–Stokes forcing (e.g., Breivik et al. 2015 ; Suzuki and Fox-Kemper 2016 ; Alari et al. 2016 ; Staneva et al. 2017 ). How changes to the wave climate will alter the Stokes drift and the associated depth-integrated Stokes transport in the future is thus of practical and scientific interest. The Stokes drift profile can be

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S. A. Thorpe, T. R. Osborn, J. F. E. Jackson, A. J. Hall, and R. G. Lueck

1. Introduction Momentum and gas exchange between the atmosphere and the ocean are known to involve wave breaking, bubble and turbulence generation, mixing by Langmuir circulation (hereinafter, for brevity, referred to as Lc) and shear-induced turbulence, all of them processes that are poorly known. This is an investigation of the relative contributions of these processes to turbulence in the upper ocean. In January 1988 efforts to make measurements of turbulence and bubbles from the U.S. Navy

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Johannes R. Gemmrich and David M. Farmer

and seek an interpretation in terms of wave-induced turbulence and Langmuir circulation. Measurements of velocity fluctuations in the surface layer in Lake Ontario at significant wave heights of ∼0.3 m ( Agrawal et al. 1992 ) provided evidence of enhanced near-surface turbulence, attributed to breaking waves, previously indicated in wave tank measurements ( Rapp and Melville 1990 ). Further support for elevated turbulence levels in the oceanic surface layer at wind speeds up to 13 m s −1 was

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Ming Li, Svein Vagle, and David M. Farmer

, rapid cooling of sea surface temperatures ( Large and Crawford 1995 ; Skyllingstad et al. 2000 ). One aspect that has not been adequately addressed within the context of OML’s response to storm forcing concerns the role of surface wave effects and Langmuir circulation. Although Langmuir circulation (LC) has long been suggested to be a major mechanism in generating turbulent mixing in OML in strong wind conditions ( Langmuir 1938 ; Leibovich 1983 ), it remains unclear if LC directly contributes to

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S. J. D. D’Alessio, K. Abdella, and N. A. McFarlane

been made to model the effects of Langmuir circulations and wave breaking, which are probably the most important processes responsible for enhanced mixing in the upper ocean. Subsequent sections are organized as follows. In section 2 we present the modeling equations along with the forcing conditions and briefly discuss the physics. A means of estimating the boundary layer depth is outlined, while the rational behind the turbulent flux expressions is included in the appendix . Then, in section

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Yalin Fan and Stephen M. Griffies

-profile parameterization ( Large et al. 1994 ) and three variations using the alternative mixing parameterizations. a. Langmuir turbulence parameterization The dynamical origin of Langmuir circulation is understood as wind-driven shear instability in combination with surface wave influences related to their mean Lagrangian motion, called Stokes drift. The prevailing theoretical interpretation of Langmuir cells is derived by Craik and Leibovich (1976) , where they introduced the effect of waves on

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H. W. Wijesekera, D. W. Wang, W. J. Teague, E. Jarosz, W. E. Rogers, D. B. Fribance, and J. N. Moum

predictions from wall boundary layer scaling. The enhanced TKE dissipation rate by wave breaking is an important factor for momentum, heat, and gas transfer rates at the air–sea interface. As a response to the wind over the ocean, roll vortices are formed roughly parallel to the wind direction. These circulation patterns can be recognized by the lines of convergence at the surface, as noted by Langmuir (1938) , and they are referred as “Langmuir cells.” The orientation of these Langmuir cells is roughly

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S. A. Thorpe, M. J. Ulloa, D. Baldwin, and A. J. Hall

1. Introduction The use of upward-pointing sonar as a means to investigate the upper ocean has developed rapidly in the last 15 years. It has proved to be a useful means of collecting information about surface waves, particularly their breaking and the bubble clouds they create, surface currents, internal waves, and Langmuir circulation (see, e.g., Thorpe and Hall 1983 ; Zedel and Farmer 1991 ). Many of the observations, however, are restricted by the lack of a system with independent power

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