Using satellite altimetry and Argo floats data to study the vertical structure of mesoscale eddies in the four major Eastern Boundary Upwelling Systems

Cori Pegliasco (LEGOS, France)


Alexis Chaigneau (Institut de Recherche pour le Développement, France); Rosemary Morrow (Laboratoire d\'Etudes en Géophysique et Océanographie Spatiales, France); Yves Morel (Laboratoire d\'Etudes en Géophysique et Océanographie Spatiales, France)

Event: 2014 Ocean Surface Topography Science Team Meeting

Session: Science Results from Satellite Altimetry: Finer scale ocean processes (mesoscale and coastal)

Presentation type: Type Poster

The four major Eastern Boundary Upwelling Systems (EBUS) are populated by numerous mesoscale eddies. These eddies are preferentially generated in the near-coastal upwelling regions and propagate offshore transporting coastal waters toward the open ocean. Investigating the spatio-temporal evolution of their vertical structure along the eddy life-cycles is thus important to better understand the impact of mesoscale eddies on the cross-shore redistribution of tracers.
Firstly, using 10 years of daily satellite altimetry maps and Argo floats data, we show the mean thermohaline vertical structure of the eddies formed in the 4 EBUS and their cross-shore variations. Secondly, a clustering hierarchical classification method is applied to the Argo floats profiles located inside eddies to depict the main eddy types (e.g. surface or subsurface intensified) that coexist in the EBUS. On average, in the Peru-Chile upwelling system, anticyclonic eddies are subsurface intensified whereas cyclonic eddies are surface intensified. In the California upwelling system, surface intensified anticyclonic eddies are found in the northern part of the upwelling area whereas in the southern part they are subsurface-intensified. In this upwelling system, cyclonic eddies are surface intensified. In the Benguela upwelling system, both the anticyclonic and cyclonic eddies are subsurface intensified with large vertical extent and the most intense anomalies are found in the southern part of the upwelling area. Finally, in the Canary upwelling system, cyclonic eddies are intensified sligtly above the anticyclonic eddies, but each are composed by different eddies types without spatial location pattern.
Thus, despite similar near coastal large-scale dynamics in each EBUS, the eddies exhibit distinct vertical characteristics.

Cori Pegliasco