The Role of Whitecapping in Thickening the Ocean Surface Boundary Layer

The 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 adj...

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Main Authors: Gerbi, Gregory P., Kastner, Samuel E., Brett, Genevieve Elizabeth
Other Authors: Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Format: Article
Language:en_US
Published: American Meteorological Society 2016
Online Access:http://hdl.handle.net/1721.1/101394
https://orcid.org/0000-0001-6170-8633
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author Gerbi, Gregory P.
Kastner, Samuel E.
Brett, Genevieve Elizabeth
author2 Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
author_facet Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Gerbi, Gregory P.
Kastner, Samuel E.
Brett, Genevieve Elizabeth
author_sort Gerbi, Gregory P.
collection MIT
description The 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.
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spelling mit-1721.1/1013942022-09-27T20:38:23Z The Role of Whitecapping in Thickening the Ocean Surface Boundary Layer Gerbi, Gregory P. Kastner, Samuel E. Brett, Genevieve Elizabeth Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Woods Hole Oceanographic Institution Brett, Genevieve Elizabeth The 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. 2016-03-02T01:57:12Z 2016-03-02T01:57:12Z 2015-08 2015-05 Article http://purl.org/eprint/type/JournalArticle 0022-3670 1520-0485 http://hdl.handle.net/1721.1/101394 Gerbi, Gregory P., Samuel E. Kastner, and Genevieve Brett. “The Role of Whitecapping in Thickening the Ocean Surface Boundary Layer.” Journal of Physical Oceanography 45, no. 8 (August 2015): 2006–2024. © 2015 American Meteorological Society https://orcid.org/0000-0001-6170-8633 en_US http://dx.doi.org/10.1175/jpo-d-14-0234.1 Journal of Physical Oceanography Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Meteorological Society American Meteorological Society
spellingShingle Gerbi, Gregory P.
Kastner, Samuel E.
Brett, Genevieve Elizabeth
The Role of Whitecapping in Thickening the Ocean Surface Boundary Layer
title The Role of Whitecapping in Thickening the Ocean Surface Boundary Layer
title_full The Role of Whitecapping in Thickening the Ocean Surface Boundary Layer
title_fullStr The Role of Whitecapping in Thickening the Ocean Surface Boundary Layer
title_full_unstemmed The Role of Whitecapping in Thickening the Ocean Surface Boundary Layer
title_short The Role of Whitecapping in Thickening the Ocean Surface Boundary Layer
title_sort role of whitecapping in thickening the ocean surface boundary layer
url http://hdl.handle.net/1721.1/101394
https://orcid.org/0000-0001-6170-8633
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