Laboratoire d’Océanographie Physique et Biogéochimique
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Séminaire d’Annalisa Griffa
par - 14 janvier 2009
mardi 10 février à 14h00 Déplacé à une date ultérieure - suite au mouvement de grève en cours
Cyclonic and anticyclonic motion in the global upper ocean from drifters : from large eddies to submeso- scale
Annalisa Griffa (Research Professor au RSMAS de l’Université de Miami et chercheure au CNR La Spezia) présentera un séminaire le mardi 10 février à 14h00 en salle de réunion du COM à Luminy :
“Cyclonic and anticyclonic motion in the global upper ocean from drifters : from large eddies to submesoscale”
Upper ocean variability is highly energetic and contributes to key processes such as heat transport and water mass formation. Here, the distribution of surface cyclonic and anticyclonic motion is computed from global drifter observations for scales from large eddies (100 km) to submesocale structures (10-20 km). Two zonal bands of small-scale motion are recovered : a known anticyclonic band at 30-40° latitude, mostly wind-induced, and an unexpected cyclonic band at 10-20° latitude. It is suggested that this is due to submesoscale processes related to salinity front instabilities. Submesoscale dynamics contributes to mixed layer restratification and subsurface water formation, with climate implication for sea interaction and exchanges with the stratified interior. These results provide a first global view of the upper ocean including these motions.
