Surface oceanic circulation along the S-SE coast of Brazil, obtanined by satellite tracked drifters / Analise da circulacao superficial oceanica na costa Sudeste-Sul do Brasil, a partir da utilizacao dos dados de derivadores rastreados por satelites

AUTOR(ES)
DATA DE PUBLICAÇÃO

1998

RESUMO

This study is about the surface oceanic circulation in the Southwest Atlantic, in particular along the South-Southeast coast of Brazil (22°S,43°W to 38°S,53°W). The data utilized are obtained from 13 WOCE (World Ocean Circulation) standard LCDs (Low Cost Drifters), launched in 1993 and 1994, as part of project COROAS (Oceanic Circulation in the Western Region of the South Atlantic). Due to the fact that these drifters had been launched in groups of 5, at semestral intervals, it was possible to analyse the mean semestral velocities of these parameters between the 1st semester of 1994. The results showed that there was uniformity, even between the different seasons, as well as the tendency of the currents to flow over the 200 m, 1000 m e 2000m isobaths. However, the mean velocities of these currents varied significantly, smaller values being observed in the 2nd semester. Between the 1st semester of 1993 and the 1st semester of 1994, relevant differences in both the mean conditions and perturbations of the circulation were verified. It is shown in this work that these variations were due to the anomalies in the regimes of the meteorological systems verified for the year of 1993. The analysis of the Kinetic Energy of Vortices (EKE) and the Mean Kinetic Energy (MKE) pointed to the great importance of the mesoscale perturbations on the circulation of the waters of the region in question. It was also observed that there was variability in regard to the mean position of the Brasil Current; sometimes the Brazil Current is deflected toward the open ocean. One of the groups of drifters exhibited an atypical deflection in position at 30°S, the result of the intrusion of the Malvinas Currentes northward, along the Continental Platform of Brazil. The parameters associated with the various vortices detected are presented; and one can observe the importance of these in the characterization of the local circulation. The spectral analysis of the data indicated that the principal sources of energy for the detected periodicities are due to meteorological effects, together with the passing of vortices and the meandering of the Brazil Current.

ASSUNTO(S)

oceanografia satelites meteorologicos boias de deriva sistema argos meandramentos sistema de aquisicao de dados oceanograficos escoamento turbulento

ACESSO AO ARTIGO

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