Deep lenses of circumpolar water in the Argentine Basin.

• Published in: Journal of Geophysical Research
• Main Authors: Arhan, Michel, Carton, X., Piola, A., Zenk, W.
• Other Authors: Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Servicio de Hidrografia Naval, Servicio de Hydrografia Naval, Institut für Meereskunde Kiel (IFMK), Christian-Albrechts-Universität zu Kiel (CAU)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2002
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Argentine; Falkland Escarpment; North Atlantic Deep Water; North Atlantic
• Online Access: https://hal.science/hal-00276433; https://doi.org/10.1029/2001JC000963

International audience Three deep anticyclonic eddies of a species only reported once before [ Gordon and Greengrove, 1986 ] were intersected by hydrographic lines of the World Ocean Circulation Experiment (WOCE) and South Atlantic Ventilation Experiment (SAVE) programs in the Argentine Basin. The vortices are centered near 3500 m depth at the interface between North Atlantic Deep Water and Bottom Water. They have ∼1500-m-thick cores containing Lower Circumpolar Deep Water and a dynamic influence that may span up to two thirds of the water column. As one eddy was observed just downstream of the western termination of the Falkland Escarpment, a destabilization of the deep boundary current by the sudden slope relaxation is suggested as a potential cause of eddy formation. Besides isopycnal interleaving at the eddy perimeters, strongly eroded core properties in the upper parts of the lenses, associated with low density ratios, hint at double diffusion at the top of the structures as another major decay mechanism. The presence of an eddy in the northern Argentine Basin shows the possibility for a northward drift of the vortices, in this basin at least. Deep events in recent current measurements from the Vema Channel are presented that raise the question of further equatorward motion to the Brazil Basin.