a) Scheme of the Kelvin wave propagations along the equator and along the African coast with bathymetry (colors), b) and c) Sea Level Anomaly (SLA, cm) for wave period range (between 30 and 90 days): (b) along the equator (20°W-10°E) and (c) along the coast of Africa (0° and 30°S). (Michon et al., in prep).
The main objective of this project is to use altimetry, both single-mission and multi-mission (T/P, ERS, JASON 1, 2 and 3) using the long-term series of altimetry data to study the local versus remote forcing in the Eastern Boundary Upwelling Systems at different time scales: intra-seasonal to interannual, as well as decadal scales and the detection of any trends. Despite the significant advances based on observations and theories/models, the issue of the relative contribution of the remote versus local forcing on the Eastern Boundary Upwelling Systems (EBUS) remains unresolved.
We will use the altimetry data in conjunction with other remotely sensed data such as surface winds (ERS, QuikSCAT, ASCAT), sea surface temperature (AVHRR, TMI,...), ocean colour (SeaWiFS, MODIS/Aqua, MERIS), new Sea Surface Salinity (SSS from SMOS), to address the following three issues:
- The influence of local forcing, the winds, on the EBUS forced by the large scale atmospheric circulation (South Atlantic Anticyclone),
- The influence of the remote forcing on the EBUS: Kelvin waves coming from the equatorial area, circulation (poleward/equatorward currents, and associated fronts),
- The influence of other processes generated locally in the EBUS for the dynamics of these areas as well as the connection of the EBUS with the open ocean: (sub)mesoscale processes : Rossby waves, eddies, filaments, fronts,..
The study will be focused in the Southern Hemisphere where two Eastern Boundary Upwelling Systems in South Atlantic and South Pacific Oceans are the most productive of the global ocean and present a strong link with the equatorial variability.