author = "Vianna, Marcio L. and Menezes, Vivian V. de",
                title = "Further evidence for a tropical water gyre in the Southwestern 
                 year = "2002",
         organization = "Simp{\'o}sio Brasileiro de Oceanografia, 1.",
             keywords = "OCEANOGRAFIA.",
             abstract = "Two views for the gyre structure of the upper layer geostrophic 
                         circulation in the southwestern Atlantic Ocean has been presented 
                         in the literature: (i)a single gyre, limited in the north at 
                         10S-15S, and in the south by the Brazil-Malvinas confluence, with 
                         a recirculation cell centered at 35o S, and (ii)a double-gyre 
                         structure, with the northern gyre dominated by a single water 
                         mass, the Salinity Maximum Water (SMW), with about the same 
                         northern limit, but with its southern limb coinciding with a 
                         subtropical front and its associated eastward current at about 28o 
                         S. We discuss evidence favoring the double-gyre view, by focusing 
                         on analysis of new data (ADCP, hydrographic and Topex/ERS 
                         altimeter). Evidence supporting the existence of a strong (50 
                         cm/s)geostrophic eastward current at 28o S, and a Brazil Current 
                         upper layer retroflection near this latitude, is described. This 
                         eastward current reaches depths of 300m, and its dynamics may be 
                         the same as the open-ocean Subtropical Countercurrents of the 
                         north Pacific and Atlantic oceans. Transport estimates will be 
                         presented. The detailed structure of recirculation cells inside 
                         this gyre domain is presented, and its annual cycle described. It 
                         is shown that while variability to the east of the gyre domain is 
                         dominated by Rossby waves, inside its domain the gyre is dominated 
                         by frontal eddies aligned along the 28S-30S quasi-zonal front, by 
                         eddies at the shelf break and possibly by open ocean eddies 
                         related to subsidence of mixed layer water into the thermocline. 
                         The data analysis suggests future research priorities could be 
                         oriented into processes that might explain such complex 
                         interaction patterns between the atmosphere, the upper water 
                         layer, the intermediate layer and the abrupt change in the 
                         coastline, not far from the Brazilian coast, but still further 
                         into the open ocean than present-day programs. It could require a 
                         system of deep sea moorings to study the evolution of the water 
                         column, as was done in the FASINEX program in the north Atlantic. 
                         We may add that biogeographic studies reporting the discovery of 
                         the presence of a strong gradient in zooplankton biodiversity at 
                         that same latitude is suggested as consistent with the existence 
                         of the countercurrent, which also supports a rich tuna fishery 
                         exploited by fishing industry based in the city of 
  conference-location = "S{\~a}o Paulo",
      conference-year = "26-30 ago. 2002",
                label = "11380",
           targetfile = "vianna.pdf",
        urlaccessdate = "21 jan. 2021"