Energetics of internal tides around the Kerguelen Plateau from modeling and altimetry

• Published in: Journal of Geophysical Research
• Main Authors: Maraldi, C, Lyard, F, Testut, L, Coleman, R
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Geophysical Union 2011
• Subjects: Earth Sciences; Oceanography; Physical Oceanography; Antarctic; Kerguelen; The Antarctic; Antarc*
• Online Access: https://doi.org/10.1029/2010JC006515; http://ecite.utas.edu.au/75857

A barotropic tidal model, with a parameterization term to account for the internal wavedrag energy dissipation, is used to examine areas of possible M2 internal tide generationin the Kerguelen Plateau region. Barotropic energy flux and a distribution of wave dragdissipation are computed. The results suggest important conversion of barotropic energy intobaroclinic tide generation over the northern Kerguelen Plateau shelf break, consistent with atheoretical criterion based on ocean stratification, tidal forcing frequency, and bathymetricgradients. The sea surface height signatures of time‐coherent internal tides are studiedusing TOPEX/Poseidon and Jason‐1 altimeter data, whose ascending tracks cross nearlyperpendicular to the eastern and western Kerguelen Plateau shelf break. Oscillations of a fewcentimeters associated with phase‐locked internal tides propagate away fromthe plateau overdistances of several hundred kilometers with a ∼110 km wavelength. When reaching thefrontal area of the Antarctic Circumpolar Current, the internal tide cannot be identified becauseof the aliasing of mesoscale variability into the same alias band as M2. Finally, using altimeterdata, we estimate the M2 barotropic tidal power converted through the internal tide generationprocess. We find consistent values with the barotropic model parameterization estimation,which is also in good agreement with global internal tide model estimates. Combined withmodeling, this study has shown that altimetry can be used to estimate internal tide dissipation.