• Bell, T. J., 1976: The structure of internal wave spectra as determined from towed thermistor chain measurements. J. Geophys. Res., 81, 37093714, doi:10.1029/JC081i021p03709.

    • Search Google Scholar
    • Export Citation
  • Egbert, G. D., and R. D. Ray, 2000: Significant dissipation of tidal energy in the deep ocean inferred from satellite altimeter data. Nature, 405, 775778, doi:10.1038/35015531.

    • Search Google Scholar
    • Export Citation
  • Egbert, G. D., and S. Y. Erofeeva, 2002: Efficient inverse modeling of barotropic ocean tides. J. Atmos. Oceanic Technol., 19, 183204, doi:10.1175/1520-0426(2002)019<0183:EIMOBO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Erofeeva, G., and L. Egbert, 2014: TPXO8-ATLAS, v1. Oregon State University, College of Earth, Ocean, and Atmospheric Sciences, accessed 11 July 2016. [Available at http://volkov.oce.orst.edu/tides/tpxo8_atlas.html.]

  • Green, J. A. M., and J. Nycander, 2013: A comparison of tidal conversion parameterizations for tidal models. J. Phys. Oceanogr., 43, 104119, doi:10.1175/JPO-D-12-023.1.

    • Search Google Scholar
    • Export Citation
  • Green, J. A. M., J. H. Simpson, S. Legg, and M. R. Palmer, 2008: Internal waves, baroclinic energy fluxes, and mixing at the European shelf edge. Cont. Shelf Res., 28, 937950, doi:10.1016/j.csr.2008.01.014.

    • Search Google Scholar
    • Export Citation
  • Green, J. A. M., C. L. Green, G. R. Bigg, T. P. Rippeth, J. D. Scourse, and K. Uehara, 2009: Tidal mixing and the strength of the meridional overturning circulation from the Last Glacial Maximum. Geophys. Res. Lett., 36, L15603, doi:10.1029/2009GL039309.

    • Search Google Scholar
    • Export Citation
  • Green, J. A. M., J. S. Simpson, S. Thorpe, and T. P. Rippeth, 2010: Observations of internal tidal waves in the isolated seasonally stratified region of the western Irish Sea. Cont. Shelf Res., 30, 214225, doi:10.1016/j.csr.2009.11.004.

    • Search Google Scholar
    • Export Citation
  • Holloway, G., 1983: A conjecture relating oceanic internal waves and small-scale processes. Atmos.–Ocean, 21, 107122, doi:10.1080/07055900.1983.9649159.

    • Search Google Scholar
    • Export Citation
  • Hopkins, J. E., G. R. Stephenson, J. A. M. Green, and M. E. Inall, 2014: Storms modify baroclinic energy fluxes in a seasonally stratified shelf sea: Inertial-tidal interaction. J. Geophys. Res. Oceans, 119, 68636883, doi:10.1002/2014JC010011.

    • Search Google Scholar
    • Export Citation
  • Inall, M. E., T. P. Rippeth, and T. J. Sherwin, 2000: Impact of nonlinear waves on the dissipation of internal tidal energy at a shelf break. J. Geophys. Res., 105, 86878705, doi:10.1029/1999JC900299.

    • Search Google Scholar
    • Export Citation
  • Inall, M. E., D. Aleynik, T. Boyd, M. Palmer, and J. Sharples, 2011: Internal tide coherence and decay over a wide shelf sea. Geophys. Res. Lett., 38, L23607, doi:10.1029/2011GL049943.

    • Search Google Scholar
    • Export Citation
  • Kelly, S. M., J. Nash, and E. Kunze, 2010: Internal-tide energy over topography. J. Geophys. Res., 115, C06014, doi:10.1029/2009JC005618.

    • Search Google Scholar
    • Export Citation
  • Kelly, S. M., N. L. Jones, J. D. Nash, and A. F. Waterhouse, 2013: The geography of semidiurnal mode-1 internal-tide energy loss. Geophys. Res. Lett., 40, 46894693, doi:10.1002/grl.50872.

    • Search Google Scholar
    • Export Citation
  • Kunze, E., L. Rosenfeld, G. Carter, and M. Gregg, 2002: Internal waves in Monterey Submarine Canyon. J. Phys. Oceanogr., 32, 18901913, doi:10.1175/1520-0485(2002)032<1890:IWIMSC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Locarnini, R. A., and Coauthors, 2013: Temperature. Vol. 1, World Ocean Atlas 2013, NOAA Atlas NESDIS 73, 40 pp., accessed 11 July 2016. [Available online at https://www.nodc.noaa.gov/OC5/woa13/woa13data.html.]

  • MacKinnon, J. A., and M. Gregg, 2003: Shear and baroclinic energy flux on the summer New England shelf. J. Phys. Oceanogr., 33, 14621475, doi:10.1175/1520-0485(2003)033<1462:SABEFO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Melet, A., R. Hallberg, S. Legg, and K. Polzin, 2013: Sensitivity of the ocean state to the vertical distribution of internal-tide driven mixing. J. Phys. Oceanogr., 43, 602615, doi:10.1175/JPO-D-12-055.1.

    • Search Google Scholar
    • Export Citation
  • Nash, J., M. Alford, and E. Kunze, 2005: Estimating internal wave energy fluxes in the ocean. J. Atmos. Oceanic Technol., 22, 15511570, doi:10.1175/JTECH1784.1.

    • Search Google Scholar
    • Export Citation
  • Nash, J., S. Kelly, E. Shroyer, J. Moum, and T. Duda, 2012: The unpredictable nature of internal tides on continental shelves. J. Phys. Oceanogr., 42, 19812000, doi:10.1175/JPO-D-12-028.1.

    • Search Google Scholar
    • Export Citation
  • Nycander, J., 2005: Generation of internal waves in the deep ocean by tides. J. Geophys. Res., 110, C10028, doi:10.1029/2004JC002487.

  • Osborne, A. R., T. L. Burch, and R. I. Scarlet, 1978: The influence of internal waves on deep-water drilling. J. Pet. Technol., 30, 14971504, doi:10.2118/6913-PA.

    • Search Google Scholar
    • Export Citation
  • Palmer, M., G. R. Stephenson, M. E. Inall, C. Balfour, A. Dusterhus, and J. A. M. Green, 2015: Turbulence and mixing by internal waves in the Celtic Sea determined from ocean glider microstructure measurements. J. Mar. Syst., 144, 5769, doi:10.1016/j.jmarsys.2014.11.005.

    • Search Google Scholar
    • Export Citation
  • Pinkel, R., 2008: Advection, phase distortion, and the frequency spectrum of finescale fields in the sea. J. Phys. Oceanogr., 38, 291313, doi:10.1175/2007JPO3559.1.

    • Search Google Scholar
    • Export Citation
  • Rippeth, T., and M. Inall, 2002: Observations of the internal tide and associated mixing across the Malin shelf. J. Geophys. Res., 107, 11 98011 990, doi:10.1029/2000JC000761.

    • Search Google Scholar
    • Export Citation
  • Robins, P., and A. J. Elliott, 2009: The internal tide of the Gareloch, a Scottish fjord. Estuarine Coastal Shelf Sci., 81, 130142, doi:10.1016/j.ecss.2008.10.022.

    • Search Google Scholar
    • Export Citation
  • Sharples, J., C. Moore, and E. Abraham, 2001: Internal tide dissipation, mixing, and vertical nitrate flux at the shelf edge of NE New Zealand. J. Geophys. Res., 106, 14 06914 081, doi:10.1029/2000JC000604.

    • Search Google Scholar
    • Export Citation
  • Sharples, J., and Coauthors, 2007: Spring-neap modulation of internal tide mixing and vertical nitrate fluxes at a shelf edge in summer. Limnol. Oceanogr., 52, 17351747, doi:10.4319/lo.2007.52.5.1735.

    • Search Google Scholar
    • Export Citation
  • Shroyer, E., J. N. Moum, and J. Nash, 2011: Nonlinear internal waves over New Jersey’s continental shelf. J. Geophys. Res., 116, C03022, doi:10.1029/2010JC006332.

    • Search Google Scholar
    • Export Citation
  • Stephenson, G. R., J. E. Hopkins, J. A. M. Green, M. E. Inall, and M. R. Palmer, 2015: Baroclinic energy flux at the continental shelf edge modified by wind-mixing. Geophys. Res. Lett., 42, 18261833, doi:10.1002/2014GL062627.

    • Search Google Scholar
    • Export Citation
  • Vlasenko, V., N. Stashchuk, M. Inall, and J. E. Hopkins, 2014: Tidal energy conversion in a global hot spot: On the 3-D dynamics of baroclinic tides at the Celtic Sea shelf break. J. Geophys. Res. Oceans, 119, 32493265, doi:10.1002/2013JC009708.

    • Search Google Scholar
    • Export Citation
  • Wunsch, C., and R. Ferrari, 2004: Vertical mixing, energy, and the general circulation of the oceans. Annu. Rev. Fluid Mech., 36, 281314, doi:10.1146/annurev.fluid.36.050802.122121.

    • Search Google Scholar
    • Export Citation
  • Zweng, M., and Coauthors, 2013: Salinity. Vol. 2, World Ocean Atlas 2013, NOAA Atlas NESDIS 74, 39 pp., accessed 11 July 2016. [Available online at https://www.nodc.noaa.gov/OC5/woa13/woa13data.html.]

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 79 28 0
PDF Downloads 64 24 0

Systematic Bias in Baroclinic Energy Estimates in Shelf Seas

View More View Less
  • 1 School of Ocean Science, Bangor University, Menai Bridge, Anglesey, United Kingdom
  • | 2 Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll, United Kingdom
Restricted access

Abstract

A simple model of an internal wave advected by an oscillating barotropic flow suggests flaws in standard approaches to estimating properties of the internal tide. When the M2 barotropic tidal current amplitude is of similar size to the phase speed of the M2 baroclinic tide, spectral and harmonic analysis techniques lead to erroneous estimates of the amplitude, phase, and energy in the M2 internal tide. In general, harmonic fits and bandpass or low-pass filters that attempt to isolate the lowest M2 harmonic significantly underestimate the strength of M2 baroclinic energy fluxes in shelf seas. Baroclinic energy flux estimates may show artificial spatial variability, giving the illusion of sources and sinks of energy where none are actually present. Analysis of previously published estimates of baroclinic energy fluxes in the Celtic Sea suggests this mechanism may lead to values being 25%–60% too low.

Denotes Open Access content.

Current affiliation: University of Southern Mississippi, Stennis Space Center, Mississippi.

Current affiliation: University of Edinburgh, School of Geosciences, Edinburgh, United Kingdom.

Corresponding author address: J. A. Mattias Green, Bangor University, School of Ocean Science, Menai Bridge, Anglesey, LL59 5AB, United Kingdom. E-mail: m.green@bangor.ac.uk

Abstract

A simple model of an internal wave advected by an oscillating barotropic flow suggests flaws in standard approaches to estimating properties of the internal tide. When the M2 barotropic tidal current amplitude is of similar size to the phase speed of the M2 baroclinic tide, spectral and harmonic analysis techniques lead to erroneous estimates of the amplitude, phase, and energy in the M2 internal tide. In general, harmonic fits and bandpass or low-pass filters that attempt to isolate the lowest M2 harmonic significantly underestimate the strength of M2 baroclinic energy fluxes in shelf seas. Baroclinic energy flux estimates may show artificial spatial variability, giving the illusion of sources and sinks of energy where none are actually present. Analysis of previously published estimates of baroclinic energy fluxes in the Celtic Sea suggests this mechanism may lead to values being 25%–60% too low.

Denotes Open Access content.

Current affiliation: University of Southern Mississippi, Stennis Space Center, Mississippi.

Current affiliation: University of Edinburgh, School of Geosciences, Edinburgh, United Kingdom.

Corresponding author address: J. A. Mattias Green, Bangor University, School of Ocean Science, Menai Bridge, Anglesey, LL59 5AB, United Kingdom. E-mail: m.green@bangor.ac.uk
Save