Cruise around Kerguelen Island

Image of the Month - April 2009

Near real time absolute dynamic topography and corresponding surface geostrophic currents during the TRACK cruise, compared with L-ADCP measurements at the surface. Three moorings have been deployed underneath Jason ground track # 94 for a one year period.

The Kerguelen Plateau forms a major topographic barrier to the path of the Antarctic Circumpolar Current, with the exception of the Fawn Trough passage, a deep passage (2650 m) located in the central part of the Kerguelen Plateau (56°S). The existence of an important current in this passage has been recently confirmed by hydrographic observations from elephant seals carrying instruments to measure the physical parameters of their environment. Although  the Fawn Trough role as a privileged passage for the transport of water masses from the Enderby Basin to the Australian Antarctic Basin appears more and more evident, no systematic measurements of currents and hydrographic parameters specially dedicated to have been made until now.

The TRACK (Transport across the Kerguelen Plateau) project is a French contribution to the International Polar Year activities. Its general objective is to fill a gap in our knowledge on the physics and dynamic of the Southern Ocean. In particular, TRACK proposes to quantify the transport of the Antarctic Circumpolar Current passing through the Fawn Trough. It is also to determine the exchange of circumpolar water masses between basins of either side of the plateau, and to test the feasibility of monitoring the transport variability using satellite altimetry.

The project is based on two oceanographic cruises on board R/V Marion Dufresne II in 2009 and 2010, involving mooring deployment and recovery, intensive hydrographic measurements, and float deployments. The TRACK project is funded by Ipev, Cnes and  Insu

During the fisrt cruise (arch 2009), near real time altimetry proved a valuable tool for the deployment, showing overall good agreement with in situ surface currents measured by LADCP. This synoptic view of surface currents in real time is of great interest to confirm or refine the cruise plan and in particular to adjust Argo float deployment position.

It must be noted that, among the drifters launched, two were part of the Argonautica educational project, one built by a French middle school (Jeliote) the other one a "profesional" drifter (Lasseube) (see Une bouée nommée Jéliote, Cnes educational web site) .

 

See also:

Websites on this subject:

  • LOcean
  • Ipev (Institut Paul-Emile Victor)