• Alves, J. H., M. L. Banner, and I. R. Young, 2003: Revisiting the Pierson–Moskowitz asymptotic limits for fully developed wind waves. J. Phys. Oceanogr., 33 , 13011323.

    • Search Google Scholar
    • Export Citation
  • Belcher, S. E., and J. C. R. Hunt, 1993: Turbulent shear flow over slowly moving waves. J. Fluid Mech., 251 , 109148.

  • Belcher, S. E., and J. C. R. Hunt, 1998: Turbulent flow over hills and waves. Annu. Rev. Fluid Mech., 30 , 507538.

  • Cohen, J. E., and S. E. Belcher, 1999: Turbulent shear flow over fast-moving waves. J. Fluid Mech., 386 , 345371.

  • Donelan, M. A., 1990: Air–sea interaction. The Sea, B. LeMehaute and D. M. Hanes, Eds., Ocean Engineering Science, Vol. 9, John Wiley and Sons, 239–291.

    • Search Google Scholar
    • Export Citation
  • Donelan, M. A., J. Hamilton, and W. H. Hui, 1985: Directional spectra of wind generated waves. Philos. Trans. Roy. Soc. London, 315 , 509562.

    • Search Google Scholar
    • Export Citation
  • Donelan, M. A., W. M. Drennan, and K. B. Katsaros, 1997: The air–sea momentum flux in conditions of wind sea and swell. J. Phys. Oceanogr., 27 , 20872099.

    • Search Google Scholar
    • Export Citation
  • Drennan, W. M., H. C. Graber, D. Hauser, and C. Quentin, 2003: On the wave age dependence of wind stress over pure wind seas. J. Geophys. Res., 108 .8062, doi:10.1029/2000JC000715.

    • Search Google Scholar
    • Export Citation
  • Drennan, W. M., K. K. Kahma, and M. A. Donelan, 1999: On momentum flux and velocity spectra over waves. Bound.-Layer Meteor., 92 , 489515.

    • Search Google Scholar
    • Export Citation
  • Edson, J., and Coauthors, 2007: The coupled boundary layers and air–sea transfer experiment in low winds. Bull. Amer. Meteor. Soc., 88 , 341356.

    • Search Google Scholar
    • Export Citation
  • Grachev, A. A., and C. W. Fairall, 2001: Upward momentum transfer in the marine boundary layer. J. Phys. Oceanogr., 31 , 16981711.

  • Grachev, A. A., C. W. Fairall, J. E. Hare, J. B. Edson, and S. D. Miller, 2003: Wind stress vector over ocean waves. J. Phys. Oceanogr., 33 , 24082429.

    • Search Google Scholar
    • Export Citation
  • Hara, T., and S. E. Belcher, 2002: Wind forcing in the equilibrium range of wind-wave spectra. J. Fluid Mech., 470 , 223245.

  • Harris, D. L., 1966: The wave-driven wind. J. Atmos. Sci., 23 , 688693.

  • Hasselmann, D., and J. Bosenberg, 1991: Field measurements of wave-induced pressure over wind–sea and swell. J. Fluid Mech., 230 , 391428.

    • Search Google Scholar
    • Export Citation
  • Janssen, P. A. E. M., 1989: Wave-induced stress and the drag of air flow over sea waves. J. Phys. Oceanogr., 19 , 745754.

  • Kudryavtsev, V. N., and V. K. Makin, 2004: Impact of swell on the marine atmospheric boundary layer. J. Phys. Oceanogr., 34 , 934949.

  • Kukulka, T., and T. Hara, 2005: Momentum flux budget analysis of wind-driven air-water interfaces. J. Geophys. Res., 110 .C12020, doi:10.1029/2004JC002844.

    • Search Google Scholar
    • Export Citation
  • Makin, V. K., V. N. Kudryavtsev, and C. Mastenbroek, 1995: Drag of the sea surface. Bound.-Layer Meteor., 73 , 159182.

  • Mastenbroek, C., 1996: Wind-wave interaction. Ph.D. thesis, Delft Technical University, 118 pp.

  • Meirink, J. F., and V. K. Makin, 2000: Modelling low-Reynolds-number effects in the turbulent air flow over water waves. J. Fluid Mech., 415 , 155174.

    • Search Google Scholar
    • Export Citation
  • Phillips, O. M., 1966: The Dynamics of the Upper Ocean. 1st ed. Cambridge University Press, 336 pp.

  • Phillips, O. M., 1985: Spectral and statistical properties of the equilibrium range in wind-generated gravity waves. J. Fluid Mech., 156 , 505531.

    • Search Google Scholar
    • Export Citation
  • Pierson, W. J., and L. Moskowitz, 1964: A proposed spectral form for fully developed wind seas based on the similarity theory of S. A. Kitaigorodskii. J. Geophys. Res., 69 , 51815190.

    • Search Google Scholar
    • Export Citation
  • Plant, W. J., 1982: A relationship between wind stress and wave slope. J. Geophys. Res., 87 , 19611967.

  • Polton, J. A., D. M. Lewis, and S. E. Belcher, 2005: The role of wave-induced Coriolis–stokes forcing on the wind-driven mixed layer. J. Phys. Oceanogr., 35 , 444457.

    • Search Google Scholar
    • Export Citation
  • Smedman, A. S., M. Tjernström, and U. Högström, 1994: The near-neutral atmospheric boundary layer with no surface shearing stress: A case study. J. Atmos. Sci., 51 , 33993411.

    • Search Google Scholar
    • Export Citation
  • Smedman, A. S., U. Högström, H. Bergström, A. Rutgersson, K. K. Kahma, and H. Pettersson, 1999: A case study of air–sea interaction during swell conditions. J. Geophys. Res., 104 , 2583325851.

    • Search Google Scholar
    • Export Citation
  • Smedman, A. S., X. G. Larsén, U. Högström, K. K. Kahma, and H. Pettersson, 2003: Effect of sea state on the momentum exchange over the sea during neutral conditions. J. Geophys. Res., 108 .3367, doi:10.1029/2002JC001526.

    • Search Google Scholar
    • Export Citation
  • Snodgrass, F. E., G. W. Groves, K. F. Hasselman, G. R. Miller, W. H. Munk, and W. H. Powers, 1966: Propagation of ocean swell across the Pacific. Philos. Trans. Roy. Soc. London, 259 , 431497.

    • Search Google Scholar
    • Export Citation
  • Sullivan, P. P., J. C. McWilliams, and C-H. Moeng, 2000: Simulation of turbulent flow over idealized water waves. J. Fluid Mech., 404 , 4785.

    • Search Google Scholar
    • Export Citation
  • Sullivan, P. P., J. B. Edson, T. Hristov, and J. C. McWilliams, 2008: Large eddy simulations and observations of atmospheric marine boundary layers above non-equilibrium surface waves. J. Atmos. Sci., 65 , 12251245.

    • Search Google Scholar
    • Export Citation
  • Teixeira, M. A. C., and S. E. Belcher, 2002: On the distortion of turbulence by a progressive surface wave. J. Fluid Mech., 458 , 229267.

    • Search Google Scholar
    • Export Citation
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Wave-Driven Wind Jets in the Marine Atmospheric Boundary Layer

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  • 1 Department of Meteorology, University of Reading, Reading, United Kingdom
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Abstract

The interaction between ocean surface waves and the overlying wind leads to a transfer of momentum across the air–sea interface. Atmospheric and oceanic models typically allow for momentum transfer to be directed only downward, from the atmosphere to the ocean. Recent observations have suggested that momentum can also be transferred upward when long wavelength waves, characteristic of remotely generated swell, propagate faster than the wind speed. The effect of upward momentum transfer on the marine atmospheric boundary layer is investigated here using idealized models that solve the momentum budget above the ocean surface. A variant of the classical Ekman model that accounts for the wave-induced stress demonstrates that, although the momentum flux due to the waves penetrates only a small fraction of the depth of the boundary layer, the wind profile is profoundly changed through its whole depth. When the upward momentum transfer from surface waves sufficiently exceeds the downward turbulent momentum flux, then the near-surface wind accelerates, resulting in a low-level wave-driven wind jet. This increases the Coriolis force in the boundary layer, and so the wind turns in the opposite direction to the classical Ekman layer. Calculations of the wave-induced stress due to a wave spectrum representative of fast-moving swell demonstrate upward momentum transfer that is dominated by contributions from waves in the vicinity of the peak in the swell spectrum. This is in contrast to wind-driven waves whose wave-induced stress is dominated by very short wavelength waves. Hence the role of swell can be characterized by the inverse wave age based on the wave phase speed corresponding to the peak in the spectrum. For a spectrum of waves, the total momentum flux is found to reverse sign and become upward, from waves to wind, when the inverse wave age drops below the range 0.15–0.2, which agrees reasonably well with previously published oceanic observations.

Corresponding author address: Kirsty E. Hanley, Department of Meteorology, University of Reading, Earley Gate, P.O. Box 243, Reading RG6 6BB, United Kingdom. Email: k.e.hanley@rdg.ac.uk

Abstract

The interaction between ocean surface waves and the overlying wind leads to a transfer of momentum across the air–sea interface. Atmospheric and oceanic models typically allow for momentum transfer to be directed only downward, from the atmosphere to the ocean. Recent observations have suggested that momentum can also be transferred upward when long wavelength waves, characteristic of remotely generated swell, propagate faster than the wind speed. The effect of upward momentum transfer on the marine atmospheric boundary layer is investigated here using idealized models that solve the momentum budget above the ocean surface. A variant of the classical Ekman model that accounts for the wave-induced stress demonstrates that, although the momentum flux due to the waves penetrates only a small fraction of the depth of the boundary layer, the wind profile is profoundly changed through its whole depth. When the upward momentum transfer from surface waves sufficiently exceeds the downward turbulent momentum flux, then the near-surface wind accelerates, resulting in a low-level wave-driven wind jet. This increases the Coriolis force in the boundary layer, and so the wind turns in the opposite direction to the classical Ekman layer. Calculations of the wave-induced stress due to a wave spectrum representative of fast-moving swell demonstrate upward momentum transfer that is dominated by contributions from waves in the vicinity of the peak in the swell spectrum. This is in contrast to wind-driven waves whose wave-induced stress is dominated by very short wavelength waves. Hence the role of swell can be characterized by the inverse wave age based on the wave phase speed corresponding to the peak in the spectrum. For a spectrum of waves, the total momentum flux is found to reverse sign and become upward, from waves to wind, when the inverse wave age drops below the range 0.15–0.2, which agrees reasonably well with previously published oceanic observations.

Corresponding author address: Kirsty E. Hanley, Department of Meteorology, University of Reading, Earley Gate, P.O. Box 243, Reading RG6 6BB, United Kingdom. Email: k.e.hanley@rdg.ac.uk

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