Publications des scientifiques de l'IRD

Assassi C., Morel Yves, Vandermeirsch F., Chaigneau Alexis, Pegliasco C., Morrow R., Colas François, Fleury S., Carton X., Klein P., Cambra R. (2016). An index to distinguish surface- and subsurface-intensified vortices from surface observations. Journal of Physical Oceanography, 46 (8), p. 2529-2552. ISSN 0022-3670.

Titre du document
An index to distinguish surface- and subsurface-intensified vortices from surface observations
Année de publication
2016
Type de document
Article référencé dans le Web of Science WOS:000384030900001
Auteurs
Assassi C., Morel Yves, Vandermeirsch F., Chaigneau Alexis, Pegliasco C., Morrow R., Colas François, Fleury S., Carton X., Klein P., Cambra R.
Source
Journal of Physical Oceanography, 2016, 46 (8), p. 2529-2552 ISSN 0022-3670
In this study, the authors first show that it is difficult to reconstruct the vertical structure of vortices using only surface observations. In particular, they show that the recent surface quasigeostrophy (SQG) and interior and surface quasigeostrophy (ISQG) methods systematically lead to surface-intensified vortices, and those subsurface-intensified vortices are thus not correctly modeled. The authors then investigate the possibility of distinguishing between surface-and subsurface-intensified eddies from surface data only, using the sea surface height and the sea surface temperature available from satellite observations. A simple index, based on the ratio of the sea surface temperature anomaly and the sea level anomaly, is proposed. While the index is expected to give perfect results for isolated vortices, the authors show that in a complex environment, errors can be expected, in particular when strong currents exist in the vicinity of the vortex. The validity of the index is then analyzed using results from a realistic regional circulation model of the Peru-Chile upwelling system, where both surface and subsurface eddies coexist. The authors find that errors are mostly associated with double-core eddies (aligned surface and subsurface cores) and that the index can be useful to determine the nature of mesoscale eddies (surface or subsurface intensified) from surface (satellite) observations. However, the errors reach 24%, and some possible improvements of the index calculations are discussed.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Limnologie physique / Océanographie physique [032]
Localisation
Fonds IRD [F B010068115]
Identifiant IRD
fdi:010068115
Contact