Multiple jets in the Malvinas Current

ALBERTO R. PIOLA; BÁRBARA C. FRANCO; ELBIO D. PALMA; MARTÍN SARACENO

JOURNAL OF GEOPHYSICAL RESEARCH

AMER GEOPHYSICAL UNION

Lugar: Washington; Año: 2013 vol. 118 p. 1 - 11

0148-0227

The velocity structure of the Malvinas Current is described based on the analysis ofhigh-resolution hydrographic data and direct current observations. The data show thatthough the current width exceeds 150 km, the flow is concentrated in two relatively narrow(~10?20 km) jets. Within these cores, the direct observations indicate surface velocitiesexceeding 0.5 m.s
1. Surface drifter, satellite-derived mean dynamic topography, and seasurface temperature data suggest that the high-velocity jets are also ubiquitous features ofthe time mean circulation. Both jets appear to be continuous features extending more than900 km along the western slope of the Argentine Basin. These jets closely follow the 200and 1400m isobaths. Additional high-velocity cores are apparent in direct currentmeasurements and hydrographic observations, but these features are weaker and notcontinuous along the slope. Though the Malvinas Current transport is mostly barotropic,baroclinic jets are also identified in relative geostrophic velocity sections. The baroclinicjets are colocated with the barotropic jets. Our results suggest that the main MalvinasCurrent core is located over a relatively flat portion of the bottom, referred to as the PeritoMoreno terrace. This observation is in agreement with recent seismic and geologicalevidence suggesting that in geological time scales the Malvinas Current played a key rolein the configuration of the bottom sediments over the western slope of the Argentine Basin.