EGU2020-3390
https://doi.org/10.5194/egusphere-egu2020-3390
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

A parameterization of local and remote tidal mixing

Casimir de Lavergne1, Clément Vic2, Gurvan Madec1, Fabien Roquet3, Amy Waterhouse4, Caitlin Whalen5, Yannis Cuypers1, Pascale Bouruet-Aubertot1, and Toshiyuki Hibiya6
Casimir de Lavergne et al.
  • 1LOCEAN Laboratory, Sorbonne University-CNRS-IRD-MNHN, France
  • 2LOPS Laboratory, UBO-IFREMER-CNRS-IRD, France
  • 3Department of Marine Sciences, University of Gothenburg, Sweden
  • 4Scripps Institution of Oceanography. University of California, California
  • 5Applied Physics Laboratory, University of Washington, Whasington
  • 6Department of Earth and Planetary Science, The University of Tokyo, Japan

Vertical mixing is often regarded as the Achilles’ heel of ocean models. In particular, few models include a comprehensive and energy-constrained parameterization of mixing by internal ocean tides. Here, we present an energy-conserving mixing scheme which accounts for the local breaking of high-mode internal tides and the distant dissipation of low-mode internal tides. The scheme relies on four static two-dimensional maps of internal tide dissipation, constructed using mode-by-mode Lagrangian tracking of energy beams from sources to sinks. Each map is associated with a distinct dissipative process and a corresponding vertical structure. Applied to an observational climatology of stratification, the scheme produces a global three-dimensional map of dissipation which compares well with available microstructure observations and with upper-ocean finestructure mixing estimates. Implemented in the NEMO global ocean model, the scheme improves the representation of deep water-mass transformation and obviates the need for a constant background diffusivity.

How to cite: de Lavergne, C., Vic, C., Madec, G., Roquet, F., Waterhouse, A., Whalen, C., Cuypers, Y., Bouruet-Aubertot, P., and Hibiya, T.: A parameterization of local and remote tidal mixing, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3390, https://doi.org/10.5194/egusphere-egu2020-3390, 2020

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