• Alford, M. H., , and R. Pinkel, 2000: Observations of overturning in the thermocline: The context of ocean mixing. J. Phys. Oceanogr., 30 , 805832.

    • Search Google Scholar
    • Export Citation
  • Aucan, J., , M. A. Merrifield, , D. S. Luther, , and P. Flament, 2006: Tidal mixing events on the deep flanks of Kaena Ridge, Hawaii. J. Phys. Oceanogr., 36 , 12021219.

    • Search Google Scholar
    • Export Citation
  • Batchelor, G. K., 1959: Small-scale variation of convected quantitites like temperature in turbulent fluid. J. Fluid Mech., 5 , 113139.

    • Search Google Scholar
    • Export Citation
  • D’Asaro, E. A., , and R-C. Lien, 2000: The wave–turbulence transition for stratified flows. J. Phys. Oceanogr., 30 , 16691678.

  • Dillon, T. M., 1982: Vertical overturns: A comparison of Thorpe and Ozmidov length scales. J. Geophys. Res., 87 , 96019613.

  • Dugan, J. P., , W. D. Morris, , and B. S. Okawa, 1986: Horizontal wave number distribution of potential energy in the ocean. J. Geophys. Res., 91 , 1299313000.

    • Search Google Scholar
    • Export Citation
  • Fleury, M., , and R. Lueck, 1992: Microstructure in and around a double-diffusive interface. J. Phys. Oceanogr., 22 , 701718.

  • Galbraith, P. S., , and D. E. Kelley, 1996: Identifying overturns in CTD profiles. J. Atmos. Oceanic Technol., 13 , 688702.

  • Gargett, A. E., 1985: Evolution of scalar spectra with the decay of turbulence in a stratified fluid. J. Fluid Mech., 159 , 379407.

  • Garrett, C. J. R., , and W. H. Munk, 1975: Space-time scales of internal waves: A progress report. J. Geophys. Res., 80 , 291297.

  • Gregg, M. C., 1989: Scaling turbulent dissipation in the thermocline. J. Geophys. Res., 94 , 96869698.

  • Gregg, M. C., 1999: Uncertainties in measuring ε and χt. J. Atmos. Oceanic Technol., 16 , 14831490.

  • Gregg, M. C., , and T. Meagher, 1980: The dynamic response of glass rod thermistors. J. Geophys. Res., 85 , 27792786.

  • Gregg, M., , and T. Sanford, 1980: Signatures of mixing from Bermuda Slope, the Sargasso Sea, and the Gulf Stream. J. Phys. Oceanogr., 10 , 105127.

    • Search Google Scholar
    • Export Citation
  • Gregg, M. C., , T. B. Sanford, , and D. P. Winkel, 2003: Reduced mixing from the breaking of internal waves in equatorial waters. Nature, 422 , 513515.

    • Search Google Scholar
    • Export Citation
  • Henyey, F. S., , J. Wright, , and S. M. Flatté, 1986: Energy and action flow through the internal wave field. J. Geophys. Res., 91 , 84878495.

    • Search Google Scholar
    • Export Citation
  • Holbrook, W. S., , and I. Fer, 2005: Ocean internal wave spectra inferred from seismic reflection transects. Geophys. Res. Lett., 32 .L15604, doi:10.1029/2005GL023733.

    • Search Google Scholar
    • Export Citation
  • Itsweire, E. C., , T. Osborn, , and T. Stanton, 1989: Horizontal distribution and characteristics of shear layers in the seasonal thermocline. J. Phys. Oceanogr., 19 , 301320.

    • Search Google Scholar
    • Export Citation
  • Johnson, H. L., , and C. Garrett, 2004: Efffects of noise on Thorpe scales and run lengths. J. Phys. Oceanogr., 34 , 23592373.

  • Katz, E. J., 1975: Tow spectra from Mode. J. Geophys. Res., 80 , 11631167.

  • Katz, E. J., , and M. G. Briscoe, 1979: Vertical coherence of the internal wave field from towed sensors. J. Phys. Oceanogr., 9 , 518530.

    • Search Google Scholar
    • Export Citation
  • Klymak, J. M., , and M. C. Gregg, 2004: Tidally generated turbulence over the Knight Inlet sill. J. Phys. Oceanogr., 34 , 11351151.

  • Klymak, J. M., , and J. N. Moum, 2007: Oceanic isopycnal slope spectra. Part I: Internal waves. J. Phys. Oceanogr., 37 , 12151231.

  • Klymak, J. M., and Coauthors, 2006: An estimate of tidal energy lost to turbulence at the Hawaiian Ridge. J. Phys. Oceanogr., 36 , 11481164.

    • Search Google Scholar
    • Export Citation
  • Kunze, E. L., , L. K. Rosenfeld, , G. S. Carter, , and M. C. Gregg, 2002: Internal waves in Monterey Submarine Canyon. J. Phys. Oceanogr., 32 , 18901913.

    • Search Google Scholar
    • Export Citation
  • Lee, C. M., , E. Kunze, , T. B. Sanford, , J. D. Nash, , M. A. Merrifield, , and P. E. Holloway, 2006: Internal tides and turbulence along the 3000-m isobath of the Hawaiian Ridge. J. Phys. Oceanogr., 36 , 11651183.

    • Search Google Scholar
    • Export Citation
  • Levine, E. R., , and R. G. Lueck, 1999: Turbulence measurements with an autonomous underwater vehicle. J. Atmos. Oceanic Technol., 16 , 15331544.

    • Search Google Scholar
    • Export Citation
  • Levine, M. D., , and T. J. Boyd, 2006: Tidally forced internal waves and overturns observed on a slope: Results from HOME. J. Phys. Oceanogr., 36 , 11841201.

    • Search Google Scholar
    • Export Citation
  • Lindborg, E., 2006: The energy cascade in a strongly stratified fluid. J. Fluid Mech., 550 , 207242.

  • MacKinnon, J., , and M. Gregg, 2003: Shear and baroclinic energy flux on the summer New England shelf. J. Phys. Oceanogr., 33 , 14621475.

    • Search Google Scholar
    • Export Citation
  • Marmorino, G., 1987: Observations of small-scale mixing processes in the seasonal thermocline. Part II: Wave breaking. J. Phys. Oceanogr., 17 , 13481355.

    • Search Google Scholar
    • Export Citation
  • McKean, R. S., 1974: Internal wave measurements in the presence of fine-structure. J. Phys. Oceanogr., 4 , 200213.

  • McKean, R. S., , and T. E. Ewart, 1974: Temperature spectra in the deep ocean off Hawaii. J. Phys. Oceanogr., 4 , 191199.

  • Moum, J. N., 1990: The quest for κρ–preliminary results from direct measurements of turbulent fluxes in the ocean. J. Phys. Oceanogr., 20 , 19801984.

    • Search Google Scholar
    • Export Citation
  • Moum, J. N., 1996a: Efficiency of mixing in the main thermocline. J. Geophys. Res., 101 , 1205912069.

  • Moum, J. N., 1996b: Energy-containing scales of turbulence in the ocean thermocline. J. Geophys. Res., 101 , 1409514109.

  • Moum, J. N., , and R. G. Lueck, 1985: Causes and implications of noise in oceanic dissipation measurements. Deep-Sea Res., 32 , 379390.

  • Moum, J. N., , M. C. Gregg, , R. C. Lien, , and M. Carr, 1995: Comparison of turbulence kinetic energy dissipation rate estimates from two ocean microstructure profilers. J. Atmos. Oceanic Technol., 12 , 346366.

    • Search Google Scholar
    • Export Citation
  • Moum, J. N., , D. R. Caldwell, , J. D. Nash, , and G. D. Gunderson, 2002: Observations of boundary mixing over the continental slope. J. Phys. Oceanogr., 32 , 21132130.

    • Search Google Scholar
    • Export Citation
  • Moum, J. N., , D. M. Farmer, , W. D. Smyth, , L. Armi, , and S. Vagle, 2003: Structure and generation of turbulence at interfaces strained by internal solitary waves propagating shoreward over the continental shelf. J. Phys. Oceanogr., 33 , 20932112.

    • Search Google Scholar
    • Export Citation
  • Nash, J. D., , D. R. Caldwell, , M. J. Zelman, , and J. N. Moum, 1999: A thermocouple for high-speed temperature measurements in the ocean. J. Atmos. Oceanic Technol., 16 , 14741483.

    • Search Google Scholar
    • Export Citation
  • Osborn, T. R., 1980: Estimates of the local rate of vertical diffusion from dissipation measurements. J. Phys. Oceanogr., 10 , 8389.

  • Osborn, T. R., , and C. S. Cox, 1972: Oceanic fine structure. Geophys. Fluid Dyn., 3 , 321345.

  • Osborn, T. R., , and W. R. Crawford, 1980: An airfoil probe for measuring velocity fluctuations in water. Air–Sea Interactions: Instruments and Methods, F. Dobson, L. Hasse, and R. Davis, Eds., Plenum, 369–386.

    • Search Google Scholar
    • Export Citation
  • Osborn, T. R., , and R. G. Lueck, 1985: Turbulence measurements from a towed body. J. Atmos. Oceanic Technol., 2 , 517527.

  • Polzin, K. L., , J. M. Toole, , and R. W. Schmitt, 1995: Finescale parameterizations of turbulent dissipation. J. Phys. Oceanogr., 25 , 306328.

    • Search Google Scholar
    • Export Citation
  • Riley, J. J., , and S. M. deBruynKops, 2003: Dynamics of turbulence strongly influenced by buoyancy. Phys. Fluids, 15 , 20472059.

  • Rosenblum, L. J., , and G. Marmorino, 1990: Statistic of mixing patches observed in the Sargasso Sea. J. Geophys. Res., 95 , 53495357.

  • Seim, H. E., , and M. C. Gregg, 1997: The importance of aspiration and channel curvature in producing strong vertical mixing over a sill. J. Geophys. Res., 102 , 34513472.

    • Search Google Scholar
    • Export Citation
  • Smyth, W. D., , J. N. Moum, , and D. R. Caldwell, 2001: The efficiency of mixing in turbulent patches: Inferences from direct simulations and microstructure observations. J. Phys. Oceanogr., 31 , 19691992.

    • Search Google Scholar
    • Export Citation
  • Sreenivasan, K. R., 1996: The passive scalar spectrum and the Obukhov-Corrsin constant. Phys. Fluids, 8 , 189196.

  • Tennekes, H., , and J. L. Lumley, 1972: A First Course in Turbulence. The MIT Press, 300 pp.

  • Thorpe, S. A., 1977: Turbulence and mixing in a Scottish loch. Philos. Trans. Roy. Soc. London, 286A , 125181.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 59 59 12
PDF Downloads 57 57 15

Oceanic Isopycnal Slope Spectra. Part II: Turbulence

View More View Less
  • 1 Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California
  • | 2 College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon
© Get Permissions
Restricted access

Abstract

Isopycnal slope spectra were computed from thermistor data obtained using a microstructure platform towed through turbulence generated by internal tidal motions near the Hawaiian Ridge. The spectra were compared with turbulence dissipation rates ε that are estimated using shear probes. The turbulence subrange of isopycnal slope spectra extends to surprisingly large horizontal wavelengths (>100 m). A four-order-of-magnitude range in turbulence dissipation rates at this site reveals that isopycnal slope spectra ∝ ε2/3k1/3x. The turbulence spectral subrange (kx > 0.4 cpm) responds to the dissipation rate as predicted by the Batchelor model spectrum, both in amplitude and towed vertical coherence. Scales between 100 and 1000 m are modeled by a linear combination of internal waves and turbulence while at larger scales internal waves dominate. The broad bandwidth of the turbulence subrange means that a fit of spectral amplitude to the Batchelor model yields reasonable estimates of ε, even when applied at scales of tens of meters that in vertical profiles would be obscured by other fine structure.

Corresponding author address: J. Klymak, School of Earth and Ocean Sciences, University of Victoria, P.O. Box 3055, STN CSC, Victoria, BC V8W 3P6, Canada. Email: jklymak@ uvic.ca

Abstract

Isopycnal slope spectra were computed from thermistor data obtained using a microstructure platform towed through turbulence generated by internal tidal motions near the Hawaiian Ridge. The spectra were compared with turbulence dissipation rates ε that are estimated using shear probes. The turbulence subrange of isopycnal slope spectra extends to surprisingly large horizontal wavelengths (>100 m). A four-order-of-magnitude range in turbulence dissipation rates at this site reveals that isopycnal slope spectra ∝ ε2/3k1/3x. The turbulence spectral subrange (kx > 0.4 cpm) responds to the dissipation rate as predicted by the Batchelor model spectrum, both in amplitude and towed vertical coherence. Scales between 100 and 1000 m are modeled by a linear combination of internal waves and turbulence while at larger scales internal waves dominate. The broad bandwidth of the turbulence subrange means that a fit of spectral amplitude to the Batchelor model yields reasonable estimates of ε, even when applied at scales of tens of meters that in vertical profiles would be obscured by other fine structure.

Corresponding author address: J. Klymak, School of Earth and Ocean Sciences, University of Victoria, P.O. Box 3055, STN CSC, Victoria, BC V8W 3P6, Canada. Email: jklymak@ uvic.ca

Save