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Accueil > Équipes > Equipe MEIGE : Modélisation, Expériences et Instrumentation pour la Géophysique et l’Environnement > Diffusion scientifique > Séminaires internes

Séminaire d’équipe

Fronts de marée interne sur le "Great Meteor Seamount" et resuspension de sédiments

Louis Gostiaux 05/2008

We present a 19 days, high frequency record of temperature profiles above the eastern
shelfbreak of the Great Meteor Seamount. We used a new "NIOZ-3" high sampling
rate thermistor string developed at the Netherlands Institute for sea Research
(www.nioz.nl), which consists of 100 independent thermistors sampling temperature
at 1Hz with an accuracy of 1mK. Sensors were set 0.5m apart above a bottom-lander,
allowing high resolution measurements of temperature both in space and time in the
first 50 meters above the edge of the Great Meteor’s shelf, at a depth inbetween 550m
and 500m.
Seamounts are known to be efficient regions for internal tides generation, but also participate
in the conversion of internal waves energy to mixing and transport through
nonlinear processes. We measured strongly nonlinear fronts with evidence of overtunings
up to several tens of meters high, that are systematically associated with the
upgoing tidal flux that pushes cold water up the seamount’s slope. The backscattered
echo-intensity data from the ADCP (acoustic Doppler current profiler) mounted on
the bottom-lander revealed an important sediment resuspension associated with the
passage of the fronts, that is strongly correlated in space and time with the thermal
fronts structures.

Abstract from Geophysical Research Abstracts,
Vol. 10, EGU2008-A-00000, 2008
EGU General Assembly 2008