The AltiGlidEx project: monitoring the ocean circulation around New Caledonia from a combination of SARAL/AltiKa measurements and dedicated in situ observing systems

Fabien Durand (LEGOS, Toulouse, France, France)


Frederic Marin (LEGOS, IRD, Noumea, New Caledonia); Jean-Luc Fuda (DT-INSU, La Seyne/mer, France, France)

Event: 2014 SARAL/AltiKa workshop

Session: Oceanography

Presentation type: Type Poster

The South-West Pacific basin is a key region for the ocean circulation and the climate system of the tropical Pacific:
- it is a region where a broad westward-flowing current - the South Equatorial Current (SEC) - encounters a large number of islands and subdivides into multiple intense zonal jets.
- it is the region where thermocline waters of subtropical origin transit in their route towards the equator, giving to this area a potential role for the low-frequency modulation of El Niño - Southern Oscillation (ENSO).

The main motivation of the AltiGlidex project is to monitor, from the combination of altimeter measurements and in situ observations, the time variability of two major oceanic currents of the regional circulation in the South-West Pacific - the East Caledonia Current and the South-Caledonian Jet - that flow along the coasts of New Caledonia. This project relies both on the new SARAL/AltiKa altimeter measurements that are expected to provide accurate observations of sea level and associated geostrophic velocities in coastal regions, and on a dedicated in situ observing system that was carried out since 2010 to get insight in the main properties of these currents. This observing system includes a long-term subsurface current mooring, repeated hydrographic surveys with SLOCUM and SPRAY gliders and a dedicated oceanographic cruise. It was specifically designed to assess the performance of the AltiKa altimeter along two tracks (#202 and #746) of the SARAL satellite.

In this poster, we will present some preliminary results of this project. A direct comparison of SARAL/Altika measurements with in situ observations in the East Caledonian Current will first be presented. Then the spatial structure of these currents, and the time variability of the associated mass transport, will be discussed from the ongoing observations acquired during the AltiGlidex project.
Fabien Durand
LEGOS, Toulouse, France