• Agrawal, Y. C., E. A. Terray, M. A. Donelan, P. A. Hwang, A. J. Williams III, W. M. Drennan, K. K. Kahma, and S. A. Kitaigorodskii, 1992: Enhanced dissipation of kinetic energy beneath surface waves. Nature,359, 219–220.

  • Anis, A., and J. N. Moum, 1992: The superadiabatic surface layer of the ocean during convection. J. Phys. Oceanogr.,22, 1221–1227.

  • ——, and ——, 1995: Surface wave–turbulence interactions: Scaling ε(z) near the sea surface. J. Phys. Oceanogr.,25, 2025–2045.

  • Craig, P. D., 1996: Velocity profile and surface roughness under breaking waves. J. Geophys. Res.,101, 1265–1277.

  • ——, and M. L. Banner, 1994: Modeling wave-enhanced turbulence in the ocean surface layer. J. Phys. Oceanogr.,24, 2546–2559.

  • D’Asaro, E. A., and G. T. Dairiki, 1997: Turbulence intensity measurements in a wind-driven mixed layer. J. Phys. Oceanogr.,27, 2009–2022.

  • Drennan, W. M., K. K. Kahma, E. A. Terray, M. A. Donelan, and S. A. Kitaigorodskii, 1992: Observations of the enhancement of kinetic energy dissipation beneath breaking wind waves. Breaking Waves IUTAM Symposium, M. L. Banner and R. H. J. Grimshaw, Eds., Springer-Verlag, 95–101.

  • ——, M. A. Donelan, E. A. Terray, and K. B. Katsaros, 1996: Oceanic turbulence measurements in SWADE. J. Phys. Oceanogr.,26, 808–815.

  • Efron, B., and G. Gong, 1983: A leisurely look at bootstrap, the jackknife, and cross-validation. Amer. Stat.,37, 36–48.

  • Farmer, D., and M. Li, 1994: Oil dispersion by turbulence and coherent circulation. Ocean Eng.,21 (6), 575–586.

  • ——, and ——, 1995: Patterns of bubble clouds organized by Langmuir circulation. J. Phys. Oceanogr.,25, 1426–1440.

  • ——, and J. R. Gemmrich, 1996: Measurements of temperature fluctuations in breaking surface waves. J. Phys. Oceanogr.,26, 816–825.

  • ——, ——, and V. Polonichko, 1998: Velocity, temperature and spatial structure of Langmuir circulation. Physical Processes in Lakes and Oceans, J. Imberger, Ed., Coastal and Estuary Studies, Vol. 54, Amer. Geophys. Union.

  • Frost, W., and T. H. Moulden, 1977: Handbook of Turbulence, Vol. 1. Plenum Press, 498 pp.

  • Gemmrich, J. R., 1997: A study of turbulence and fine scale temperature variability of the ocean thermal boundary layer under breaking surface waves. Ph.D. thesis, University of Victoria, Victoria, BC, Canada, 209 pp.

  • ——, T. D. Mudge, and V. D. Polonichko, 1994: On the energy input from wind to surface waves. J. Phys. Oceanogr.,24, 2413–2417.

  • Hasse, L., 1971: The sea surface temperature deviation and the heat flow at the sea–air interface. Bound.-Layer Meteor.,1, 368–379.

  • Jessup, A. T., 1996: The infrared signature of breaking waves. The Air–Sea Interface, M. A. Donelan, W. H. Hui, and W. J. Plant, Eds., University of Toronto Press, 665–670.

  • Katsaros, K. B., 1980: The aqueous thermal boundary layer. Bound.-Layer Meteor.,18, 107–127.

  • Kitaigorodskii, S. A., 1984: On the fluid dynamical theory of turbulent gas transfer across an air–sea interface in the presence of breaking waves. J. Phys. Oceanogr.,14, 960–972.

  • Kundu, P. K., 1990: Fluid Mechanics. Academic Press, 638 pp.

  • Large, W. G., J. C. McWilliams, and S. C. Doney, 1994: Oceanic vertical mixing: A review and a model with a nonlocal boundary layer parameterization. Rev. Geophys.,32, 363–403.

  • Li, M., and C. Garrett, 1995: Is Langmuir circulation driven by surface waves or surface cooling? J. Phys. Oceanogr.,25, 64–76.

  • Mellor, G. L., and T. Yamada, 1982: Development of a turbulent closure model for geophysical fluid problems. Rev. Geophys. Space Phys.,20, 851–875.

  • Mudge, T. D., and R. G. Lueck, 1994: Digital signal processing to enhance oceanographic observations. J. Atmos. Oceanic Technol.,11, 825–835.

  • Myer, G. E., 1969: A field study of Langmuir circulations. Proc. 12th Conf. on Great Lakes Research, Ann Arbor, MI, Int. Assoc. for Great Lakes Res., 652–663.

  • Osborn, T., D. M. Farmer, S. Vagle, S. A. Thorpe, and M. Cure, 1992:Measurements of bubble plumes and turbulence from a submarine. Atmos.–Ocean,30, 419–440.

  • Polonichko, V. D., 1997: Response of the upper ocean to wind, wave and buoyancy forcing. Ph.D. thesis, University of Victoria, Victoria, BC, Canada.

  • Prandtl, L., 1925: Bericht über Untersuchungen zur ausgebildeten Turbulenz. Z. angewandte Math. Mech.,5, 136–139.

  • Rapp, R. J., and W. K. Melville, 1990: Laboratory measurements of deep-water breaking waves. Philos. Trans. Roy. Soc. London, Ser. A,331, 731–800.

  • Schlüssel, P., W. J. Emery, H. Graßl, and T. Mammen, 1990: On the bulk skin temperature difference and its impact on satellite remote sensing of sea surface temperature. J. Geophys. Res.,95, 13 341–13 356.

  • Terray, E. A., M. A. Donelan, Y. C. Agrawal, W. M. Drennan, K. K. Kahma, A. J. Williams III, P. A. Hwang, and S. A. Kitaigorodskii, 1996: Estimates of kinetic energy dissipation under breaking waves. J. Phys. Oceanogr.,26, 792–807.

  • Terrill, E., and W. K. Melville, 1997: Sound speed measurements in the surface-wave layer. J. Acoust. Soc. Amer.,102, 1–19.

  • Thorpe, S. A., 1984a: The effect of Langmuir circulation on the distribution of submerged bubbles caused by breaking wind waves. J. Fluid Mech.,142, 151–170.

  • ——, 1984b: A model of the turbulent diffusion of bubble clouds below the sea surface. J. Phys. Oceanogr.,14, 841–854.

  • ——, 1992: Bubble clouds and the dynamics of the upper ocean. Quart. J. Roy. Meteor. Soc.,118, 1–22.

  • ——, 1995: Dynamical processes of transfer at the sea surface. Progress in Oceanography, Vol. 35, Pergamon, 315–352.

  • ——, and A. J. Hall, 1982: Observations of the thermal structure of Langmuir circulation. J. Fluid Mech.,114, 237–250.

  • ——, and ——, 1987: Bubble clouds and temperature anomalies in the upper ocean. Nature,328, 48–51.

  • Woolf, D. K., and S. A. Thorpe, 1991: Bubbles and the air–sea exchange of gases in near saturation conditions. J. Mar. Res.,49, 435–466.

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Near-Surface Turbulence and Thermal Structure in a Wind-Driven Sea

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  • 1 Institute of Ocean Sciences, Sidney, British Columbia, Canada, and University of Victoria, Victoria, British Columbia, Canada
  • | 2 Institute of Ocean Sciences, Sidney, British Columbia, Canada
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Abstract

Ocean surface turbulence at high sea states is evaluated using heat as a naturally occurring passive tracer. A freely drifting instrument with a mechanically driven temperature profiler, fixed depth thermistors, and conductivity cells was used to monitor breaking wave activity and fine-scale temperature structure within the upper 2 m of the water column. The combination of temperature profiles and independent heat flux measurements demonstrate the presence of wave-enhanced turbulence and the effects of subsurface advection due to Langmuir circulation. The turbulence length scale, extracted from the temperature profile fine structure, suggests a surface value significantly smaller than previously reported. A Prandtl-type mixing length model matched with a surface energy flux due to wave breaking and the observed turbulent length scale is consistent with the authors’ observations. Both advection and enhanced diffusion are reconciled in a two-dimensional model of the upper-ocean boundary layer, providing a framework for studying Langmuir circulation and upper-ocean turbulence in terms of the measured temperature structure.

Corresponding author address: Dr. David M. Farmer, Institute of Ocean Sciences, Post Office Box 6000, Sidney, BC V8L 4B2, Canada.

Email: farmerd@dfo-mpo.gc.ca

Abstract

Ocean surface turbulence at high sea states is evaluated using heat as a naturally occurring passive tracer. A freely drifting instrument with a mechanically driven temperature profiler, fixed depth thermistors, and conductivity cells was used to monitor breaking wave activity and fine-scale temperature structure within the upper 2 m of the water column. The combination of temperature profiles and independent heat flux measurements demonstrate the presence of wave-enhanced turbulence and the effects of subsurface advection due to Langmuir circulation. The turbulence length scale, extracted from the temperature profile fine structure, suggests a surface value significantly smaller than previously reported. A Prandtl-type mixing length model matched with a surface energy flux due to wave breaking and the observed turbulent length scale is consistent with the authors’ observations. Both advection and enhanced diffusion are reconciled in a two-dimensional model of the upper-ocean boundary layer, providing a framework for studying Langmuir circulation and upper-ocean turbulence in terms of the measured temperature structure.

Corresponding author address: Dr. David M. Farmer, Institute of Ocean Sciences, Post Office Box 6000, Sidney, BC V8L 4B2, Canada.

Email: farmerd@dfo-mpo.gc.ca

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