Malvinas Current at 44.7ºS: Analysis of its Variability from in-situ Data and 25 years of Satellite Altimetry Data

SARACENO MARTIN; ARTANA, CAMILA; CHRISTINE PROVOST; GUILLERMINA PANIAGUA; LAGO, LORELEY S.; GUERRERO RAUL; FERRARI, RAMIRO; PIOLA ALBERTO

Congreso; 25 Years of Progress in Radar Altimetry Symposium,; 2018

In the framework of the CASSIS project three tallmoorings equipped with current-meters were deployedin a zonal section at 44.7ºS across the continental shelfbreakof the Southwestern Atlantic between December2015 and June 2017. The section is orthogonal to theMalvinas Current (MC) that flows northward in thislocation. This is the first time that a time series of theMC is recorded at this latitude. Previous measurementswere made at 41ºS, being strongly affected by theproximity of the Brazil-Malvinas Confluence region. The18-month twenty-day low pass filtered time series of insitu velocities obtained from the shallowest instrumentsare significantly correlated with geostrophic velocitiesobtained from a gridded altimetry product (r=0.8). Thein situ velocity measurements present large oscillations(up to 50 cm/s in less than a week). These short-termoscillations are severely smoothed in the altimetry field.The large oscillations in the in-situ observations arecoherent with the presence of multiple current jets and,during some events, of a strong, zonally oscillating jet.The altimetry data suggests that the MC broadens andstrengths alternatively and that those changes are theresult of the interaction with mesoscale activity on theeastern side of the MC. The analysis of the 25-years timeseries of altimeter data no significant trend inmagnitude of the geostrophic velocity of the MC at thislatitude