SWOT in the Tropics: High-frequency and small-scale dynamics of sea surface height around New-Caledonia from in situ observations

Guillaume Serazin (LEGOS/IRD, France)

CoAuthors

Frédéric MARIN (IRD, FRANCE); Sophie CRAVATTE (IRD, France); Lionel GOURDEAU (IRD, France); Rosemary MORROW (CNRS, France)

Event: 2017 Ocean Surface Topography Science Team Meeting

Session: Tides, internal tides and high-frequency processes

Presentation type: Type Poster

The oceanic circulation around New Caledonia involves a substantial mesoscale eddy field, associated with submesoscale features, as well as substantial internal tides generated by the steep bathymetry of the region. The future SWOT satellite will fly next to New Caledonia during the Cal/Val cycle and will provide an unprecedented opportunity to characterize the small-scale dynamics down to 20 km in this region. In order to understand the complex content of the observed small-scale sea surface height as well as the impact of the errors linked to the subsampling of scales shorter than 20 km, in situ observing systems could be deployed from the oceanographic centre of Noumea during the Cal/Val cycle. Before such a deployment, analyzing former observing dataset is worthwhile to characterize high-frequency small-scale dynamics in the region and would provide valuable feedbacks on the capacity of different observing systems to probe those dynamics during the SWOT Cal/Val Cycle.

Former glider observations are used to characterize the M2 internal tides around New Caledonia by performing a harmonic fitting on the isopycnal displacements. Such observations are also used to try to estimate high-frequency vertical velocities and detect subsmesocale fronts. Structure functions of surface velocities are computed from several ship ADCP measurements in this region to characterize the kinetic energy spectrum at small scales. A Helmotz decomposition is performed to separate divergent and rotational motions and to analyze a change in the spectrum slope. Those preliminary results will eventually be used to assess the capacity of the high-resolution MITGCM model, forced with barotropic tides, to be representative of the high-frequency and small-scale dynamics around New Caledonia.
 

Poster show times:

RoomStart DateEnd Date
Concerto Ballroom Thu, Oct 26 2017,14:00 Thu, Oct 26 2017,18:00
Guillaume Serazin
LEGOS/IRD
France
guillaume.serazin@legos.obs-mip.fr