Journal of Oceanography

, Volume 58, Issue 1, pp 11–24 | Cite as

Aspects of Deep Ocean Mixing

  • Chris Garrett
  • Louis St. Laurent


The turbulent motions responsible for ocean mixing occur on scales much smaller than those resolved in numerical simulations of oceanic flows. Great progress has been made in understanding the sources of energy for mixing, the mechanisms, and the rates. On the other hand, we still do not have adequate answers to first order questions such as the extent to which the thermohaline circulation of the ocean, and hence the earth's climate, is sensitive to the present mixing rates in the ocean interior. Internal waves, generated by either wind or flow over topography, appear to be the principle cause of mixing. Mean and eddy flows over topography generate internal lee waves, while tidal flows over topography generate internal tides. The relative importance of these different internal wave sources is unknown. There are also great uncertainties about the spatial and temporal variation of mixing. Calculations of internal tide generation are becoming increasingly robust, but we do not know enough about the subsequent behavior of internal tides and their eventual breakdown into turbulence. It does seem, however, that most internal tide energy flux is radiated away from generation sites as low modes that propagate over basin scales. The mechanisms of wave-wave interaction and topographic scattering both act to transfer wave energy from low modes to smaller dissipative scales.

Ocean mixing internal tides internal waves turbulence 


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Copyright information

© The Oceanographic Society of Japan 2002

Authors and Affiliations

  • Chris Garrett
    • 1
  • Louis St. Laurent
    • 1
  1. 1.School of Earth and Ocean SciencesUniversity of VictoriaVictoriaCanada

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