The ELISA Experiment (1997 - 1998)

ELISA stands for Eddies and Leddies  Interdisciplinary Study off Algeria. This experiment was part of the MATER (MAST3-MTP2) European program, and involved 44 physicists, biologists and geochemists from 8 countries (not to mention the persons who provided technical and logistical help!).
 

OBJECTIVES:

The main objectives of the ELISA experiment were to study, in the eastern part of the Algerian Basin:

• The general circulation of the water masses (MAW, LIW, WMDW)

• The Algerian Eddies (AEs) origin, structure, and trajectory

• The biological activity associated to the mesocale dynamical phenomena

• The role of the mesocale dynamics on the biological functioning of the Algerian Basin.

MEANS:

Work at sea was carried out in the eastern part of the Algerian Basin from July 1997 to July 1998 involving :

1 - High resolution interdisciplinary in situ study (MATER WP2/W216): campaigns at sea
 4 main campaigns were scheduled year-round i) to carry moorings operations and periodic maintenance of bio-optical moored sensors, and ii) to sample mesoscale structures.  Together with additional unexpected campaigns, ELISA shiptime totalized  ~100 days.

Thanks to the collaboration of the DLR, NOAA/AVHRR SST images were sent aboard in near-real time in order to track hydrodynamical features (AEs especially) and pinpoint sampling.
 

• ELISA-1,  July 1. to August 4. 1997 (35 days), on board  RV “Le Suroît”. It was the main campaign and interdisciplinary effort. It was divided into 3 legs respectively to put the moorings in place, make rapid synoptic surveys of an eddy with XBT’s, CTD and Seasoar (tow-yo), and lastly to biological and biogeochemical sampling in the eddy.

• ELISA-2,  October 20. to 29. 1997, on board   RV “Tethys-2”. Unexpected mooring operations and bad weather conditions prevented any coherent mesoscale sampling.

• ELISA-3, March 19. to 30. 1998, on board RV “Le Suroît”. Additional unexpected mooring operations had to be carried out, however an eddy could be sampled.

• ELISA-4, June 22. to July 8. 1998, on board RV “Le Suroît”.  All mooring lines were recovered and an eddy sampled.

Click here to access to general information about ELISA campaigns

Click here to see preliminary results
 
 

2 - Long-term monitoring of mesoscale activity (MATER WP2/W218):

• 1-year deployment of a 9-mooring network

• 1-year deployment of 15 sub-surface lagrangian floats ballasted to drift in the LIW layer

• Continuous monitoring of the Algerian Basin by satellite imagery for mesoscale phenomena detection and tracking
• Data source
• Methods

• High resolution interdisciplinary in situ study (MATER WP2/W216)
• Long-term monitoring of mesoscale activity (MATER WP2/W218)