Internal tides are known to draw around 1 Terrawatt of energy from the Earth-Moon gravitational system. This energy-flux ultimately plays an important role in ocean mixing, which in turn impacts the Earth’s climate. Numerical simulations and satellite altimetry data suggest that over 70% of the internal tide energy-flux comes from a handful of steep ocean ridges, which act as generation hot spots. Many of these ridges, however, have complicated shapes, making comprehensive field studies and numerical simulations challenging. As such, a clear picture of internal tide generation by three-dimensional topography has yet to be established.
The Luzon Strait, between Taiwan and the Philippines, is such an exceptional location with one of the strongest tides observed in the world. Surface elevations of the order of 0.5m and currents up to 1 m/s make it a source of strongly nonlinear barotropic and baroclinic tides.
An ambitious laboratory experiment at the Coriolis platform took place during the fall of 2010, in collaboration with researchers from Coriolis, ENS Lyon, MIT and Woods Hole Oceanographic Institution. The main goal of this project was to study the generation of internal tide at the Luzon Strait, taking into account the realistic 3D topography and background stratification, in order to produce a set of experimental data that would improve the present understanding based on in-situ measurements, SAR observations and numerical simulations.
publication :
Large-scale, realistic laboratory modeling of M2 internal tide generation at the Luzon Strait" , 2013 , Matthieu J. Mercier1, Louis Gostiaux, Karl Helfrich, Joel Sommeria, Samuel Viboud, Henri Didelle, Sasan J. Ghaemsaidi, Thierry Dauxois and Thomas Peacock,
Geophysical Research Letters, DOI : 10.1002/2013GL058064.
Other publications and web sites on the project :
Journal Le Monde ( 09.12.2013) : Les mystères des tsunamis sous-marins
Ecole Normale Supérieure Lyon, focus : Simuler des tsunamis internes en laboratoire (12/12/2013)
MIT front page (08/01/2014)
Scientific American : Long a Mystery, How 500-Meter-High Undersea Waves Form Is Revealed (15/01/2014)
site du CNRS (07/02/2014)