| The surface circulation in the western Argentine Basin is described based on surface drifters from the period 1990-2001, a total of over 100 drifter years, hydrographic data and numerical simulations. The data reveals well defined mean flow patterns of the Brazil and Malvinas Currents. The latter is formed by three branches of the Antarctic Circumpolar Current associated to the Subantarctic Front that deflect northward downstream of Drake Passage. These branches originate west of Burdwood Bank and at the North Scotia Ridge gaps located at 55ZW and 48ZW, and merge on the western boundary of the Argentine Basin near 48ZS. The drifter derived flow also clearly depicts the regions of tight recirculations of the western boundary currents and the South Atlantic Current. High mean and eddy kinetic energies (>2500 cm2/s2) are observed downstream of the separation of the western boundary currents from the continental margin. High eddy kinetic energy (~1000 cm2/s2) is also obseverd along the eastward extension of the Confluence and along the Falkland Escarpment Front. These features of the surface circulation are in good agreement with regional, high-resolution, numerical simulations based on the Princeton Ocean Model, forced with ECMWF winds, and tides and flows at the open boundaries derived from global models. The subsurface thermohaline structure of the model across the main currents is compared with observations from hydrographic data. |
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