Wave Breaking and Ocean Surface Layer Thermal Response

2004 ◽  
Vol 34 (3) ◽  
pp. 693-698 ◽  
Author(s):  
George Mellor ◽  
Alan Blumberg
Keyword(s):  
Surface Layer ◽  
Wave Breaking ◽  
Thermal Response ◽  
Ocean Surface ◽  
Breaking Waves ◽  
Surface Boundary ◽  
Surface Boundary Layer ◽  
Surface Temperatures ◽  
Charnock Constant ◽  
Ocean Surface Layer

Abstract The effect of breaking waves on ocean surface temperatures and surface boundary layer deepening is investigated. The modification of the Mellor–Yamada turbulence closure model by Craig and Banner and others to include surface wave breaking energetics reduces summertime surface temperatures when the surface layer is relatively shallow. The effect of the Charnock constant in the relevant drag coefficient relation is also studied.

scholarly journals Observations of Turbulence in the Ocean Surface Boundary Layer: Energetics and Transport

2009 ◽  
Vol 39 (5) ◽  
pp. 1077-1096 ◽  
Author(s):  
Gregory P. Gerbi ◽  
John H. Trowbridge ◽  
Eugene A. Terray ◽  
Albert J. Plueddemann ◽  
Tobias Kukulka
Keyword(s):  
Boundary Layer ◽  
Diffusion Coefficient ◽  
Kinetic Energy ◽  
Wave Breaking ◽  
Ocean Surface ◽  
Surface Boundary ◽  
Langmuir Turbulence ◽  
Rigid Boundary ◽  
Surface Boundary Layer ◽  
Buoyancy Forcing

Abstract Observations of turbulent kinetic energy (TKE) dynamics in the ocean surface boundary layer are presented here and compared with results from previous observational, numerical, and analytic studies. As in previous studies, the dissipation rate of TKE is found to be higher in the wavy ocean surface boundary layer than it would be in a flow past a rigid boundary with similar stress and buoyancy forcing. Estimates of the terms in the turbulent kinetic energy equation indicate that, unlike in a flow past a rigid boundary, the dissipation rates cannot be balanced by local production terms, suggesting that the transport of TKE is important in the ocean surface boundary layer. A simple analytic model containing parameterizations of production, dissipation, and transport reproduces key features of the vertical profile of TKE, including enhancement near the surface. The effective turbulent diffusion coefficient for heat is larger than would be expected in a rigid-boundary boundary layer. This diffusion coefficient is predicted reasonably well by a model that contains the effects of shear production, buoyancy forcing, and transport of TKE (thought to be related to wave breaking). Neglect of buoyancy forcing or wave breaking in the parameterization results in poor predictions of turbulent diffusivity. Langmuir turbulence was detected concurrently with a fraction of the turbulence quantities reported here, but these times did not stand out as having significant differences from observations when Langmuir turbulence was not detected.

scholarly journals Observations of the Transfer of Energy and Momentum to the Oceanic Surface Boundary Layer beneath Breaking Waves

2016 ◽  
Vol 46 (6) ◽  
pp. 1823-1837 ◽  
Author(s):  
Malcolm E. Scully ◽  
John H. Trowbridge ◽  
Alexander W. Fisher
Keyword(s):  
Vertical Velocity ◽  
Wave Breaking ◽  
Momentum Flux ◽  
Surface Flux ◽  
Breaking Waves ◽  
Surface Boundary ◽  
Wave Band ◽  
Surface Boundary Layer ◽  
Order Of Magnitude ◽  
Energy And Momentum

AbstractMeasurements just beneath the ocean surface demonstrate that the primary mechanism by which energy from breaking waves is transmitted into the water column is through the work done by the covariance of turbulent pressure and velocity fluctuations. The convergence in the vertical transport of turbulent kinetic energy (TKE) balances the dissipation rate of TKE at first order and is nearly an order of magnitude greater than the sum of the integrated Eulerian and Stokes shear production. The measured TKE transport is consistent with a simple conceptual model that assumes roughly half of the surface flux of TKE by wave breaking is transmitted to depths greater than the significant wave height. During conditions when breaking waves are inferred, the direction of momentum flux is more aligned with the direction of wave propagation than with the wind direction. Both the energy and momentum fluxes occur at frequencies much lower than the wave band, consistent with the time scales associated with wave breaking. The largest instantaneous values of momentum flux are associated with strong downward vertical velocity perturbations, in contrast to the pressure work, which is associated with strong drops in pressure and upward vertical velocity perturbations.

scholarly journals The Role of Whitecapping in Thickening the Ocean Surface Boundary Layer

2015 ◽  
Vol 45 (8) ◽  
pp. 2006-2024 ◽  
Author(s):  
Gregory P. Gerbi ◽  
Samuel E. Kastner ◽  
Genevieve Brett
Keyword(s):  
Boundary Layer ◽  
Initial Conditions ◽  
Ocean Surface ◽  
Breaking Waves ◽  
Length Scale ◽  
Surface Boundary ◽  
Transfer Velocity ◽  
Surface Boundary Layer ◽  
Turbulent Length Scale ◽  
Shear Production

AbstractThe effects of wind-driven whitecapping on the evolution of the ocean surface boundary layer are examined using an idealized one-dimensional Reynolds-averaged Navier–Stokes numerical model. Whitecapping is parameterized as a flux of turbulent kinetic energy through the sea surface and through an adjustment of the turbulent length scale. Simulations begin with a two-layer configuration and use a wind that ramps to a steady stress. This study finds that the boundary layer begins to thicken sooner in simulations with whitecapping than without because whitecapping introduces energy to the base of the boundary layer sooner than shear production does. Even in the presence of whitecapping, shear production becomes important for several hours, but then inertial oscillations cause shear production and whitecapping to alternate as the dominant energy sources for mixing. Details of these results are sensitive to initial and forcing conditions, particularly to the turbulent length scale imposed by breaking waves and the transfer velocity of energy from waves to turbulence. After 1–2 days of steady wind, the boundary layer in whitecapping simulations has thickened more than the boundary layer in simulations without whitecapping by about 10%–50%, depending on the forcing and initial conditions.

scholarly journals RESPONSE OF THE OCEAN SURFACE LAYER WITH BREAKING WAVES IN FETCH-LIMITED WIND CONDITIONS

2018 ◽  
Vol 74 (2) ◽  
pp. I_67-I_72 ◽  
Author(s):  
Ayumi SARUWATARI ◽  
Ryota SAKAGAWA ◽  
Junichi OTSUKA ◽  
Yasuyuki BABA ◽  
Teruhiro KUBO ◽  
...  
Keyword(s):  
Surface Layer ◽  
Ocean Surface ◽  
Breaking Waves ◽  
Ocean Surface Layer

Interaction of Langmuir Turbulence and Inertial Currents in the Ocean Surface Boundary Layer under Tropical Cyclones

2018 ◽  
Vol 48 (9) ◽  
pp. 1921-1940 ◽  
Author(s):  
Dong Wang ◽  
Tobias Kukulka ◽  
Brandon G. Reichl ◽  
Tetsu Hara ◽  
Isaac Ginis ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Surface Layer ◽  
Tropical Cyclones ◽  
Ocean Surface ◽  
Stokes Drift ◽  
Surface Boundary ◽  
Langmuir Turbulence ◽  
Surface Boundary Layer ◽  
Wave Forcing ◽  
Inertial Currents

AbstractBased on a large-eddy simulation approach, this study investigates the response of the ocean surface boundary layer (OSBL) and Langmuir turbulence (LT) to extreme wind and complex wave forcing under tropical cyclones (TCs). The Stokes drift vector that drives LT is determined from spectral wave simulations. During maximum TC winds, LT substantially enhances the entrainment of cool water, causing rapid OSBL deepening. This coincides with relatively strong wave forcing, weak inertial currents, and shallow OSBL depth , measured by smaller ratios of , where denotes a Stokes drift decay length scale. LT directly affects a near-surface layer whose depth is estimated from enhanced anisotropy ratios of velocity variances. During rapid OSBL deepening, is proportional to , and LT efficiently transports momentum in coherent structures, locally enhancing shear instabilities in a deeper shear-driven layer, which is controlled by LT. After the TC passes, inertial currents are stronger and is greater while is shallower and proportional to . During this time, the LT-affected surface layer is too shallow to directly influence the deeper shear-driven layer, so that both layers are weakly coupled. At the same time, LT reduces surface currents that play a key role in the surface energy input at a later stage. These two factors contribute to relatively small TKE levels and entrainment rates after TC passage. Therefore, our study illustrates that inertial currents need to be taken into account for a complete understanding of LT and its effects on OSBL dynamics in TC conditions.

scholarly journals Parameterization of Wave-Induced Mixing Using the Large Eddy Simulation (LES) (I)

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 207 ◽  
Author(s):  
Haili Wang ◽  
Changming Dong ◽  
Yongzeng Yang ◽  
Xiaoqian Gao
Keyword(s):  
Boundary Layer ◽  
Large Eddy Simulation ◽  
Ocean Surface ◽  
Breaking Waves ◽  
Global Climate Models ◽  
Surface Boundary ◽  
Surface Boundary Layer ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Wave Induced

Turbulent motions in the thin ocean surface boundary layer control exchanges of momentum, heat and trace gases between the atmosphere and ocean. However, present parametric equations of turbulent motions that are applied to global climate models result in systematic or substantial errors in the ocean surface boundary layer. Significant mixing caused by surface wave processes is missed in most parametric equations. A Large Eddy Simulation model is applied to investigate the wave-induced mixed layer structure. In the wave-averaged equations, wave effects are calculated as Stokes forces and breaking waves. To examine the effects of wave parameters on mixing, a series of wave conditions with varying wavelengths and heights are used to drive the model, resulting in a variety of Langmuir turbulence and wave breaking outcomes. These experiments suggest that wave-induced mixing is more sensitive to wave heights than to the wavelength. A series of numerical experiments with different wind intensities-induced Stokes drifts are also conducted to investigate wave-induced mixing. As the wind speed increases, the influence depth of Langmuir circulation deepens. Additionally, it is observed that breaking waves could destroy Langmuir cells mainly at the sea surface, rather than at deeper layers.

scholarly journals A global perspective on Langmuir turbulence in the ocean surface boundary layer

2012 ◽  
Vol 39 (18) ◽  
Author(s):  
Stephen E. Belcher ◽  
Alan L. M. Grant ◽  
Kirsty E. Hanley ◽  
Baylor Fox-Kemper ◽  
Luke Van Roekel ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Ocean Surface ◽  
Global Perspective ◽  
Surface Boundary ◽  
Langmuir Turbulence ◽  
Surface Boundary Layer

Methane oxidation and methane fluxes in the ocean surface layer and deep anoxic waters

Nature ◽  
1987 ◽  
Vol 327 (6119) ◽  
pp. 226-229 ◽  
Author(s):  
B. B. Ward ◽  
K. A. Kilpatrick ◽  
P. C. Novelli ◽  
M. I. Scranton
Keyword(s):  
Surface Layer ◽  
Methane Oxidation ◽  
Ocean Surface ◽  
Anoxic Waters ◽  
Methane Fluxes ◽  
Ocean Surface Layer

LESbrary: A library of large eddy simulation data for the calibration and uncertainty quantification of ocean surface boundary layer turbulence parameterizations

2021 ◽  
Author(s):  
Gregory Wagner ◽  
Andre Souza ◽  
Adeline Hillier ◽  
Ali Ramadhan ◽  
Raffaele Ferrari
Keyword(s):  
Boundary Layer ◽  
Turbulent Mixing ◽  
Large Scale ◽  
Ocean Surface ◽  
Limited Area ◽  
Surface Boundary ◽  
Model Errors ◽  
Surface Boundary Layer ◽  
Large Eddy ◽  
Free Parameters

<p>Parameterizations of turbulent mixing in the ocean surface boundary layer (OSBL) are key Earth System Model (ESM) components that modulate the communication of heat and carbon between the atmosphere and ocean interior. OSBL turbulence parameterizations are formulated in terms of unknown free parameters estimated from observational or synthetic data. In this work we describe the development and use of a synthetic dataset called the “LESbrary” generated by a large number of idealized, high-fidelity, limited-area large eddy simulations (LES) of OSBL turbulent mixing. We describe how the LESbrary design leverages a detailed understanding of OSBL conditions derived from observations and large scale models to span the range of realistically diverse physical scenarios. The result is a diverse library of well-characterized “synthetic observations” that can be readily assimilated for the calibration of realistic OSBL parameterizations in isolation from other ESM model components. We apply LESbrary data to calibrate free parameters, develop prior estimates of parameter uncertainty, and evaluate model errors in two OSBL parameterizations for use in predictive ESMs.</p>

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