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A circulação oceânica de larga-escala na região oeste do Atlântico Sul com base no modelo de circulação Global OCCAM

The OCCAM (Ocean Circulation and Climate Advanced Modeling Project) is one of the global ocean circulation models which has been commonly used by the Brazilian oceanographic community. In most cases it is associated to regional numerical modeling studies, where it provides initial and boundary conditions for higher resolution models. The aim of this work, based on the concept of water masses, is to compare on an annual basis, the OCCAM with the use of: i) climatological temperature and salinity data from the NODC (National Oceanographic Data Center) and ii) volume transports associated with the water masses and based on values available in the literature. The selected levels of comparison were chosen to represent the core of the main water masses of the South Atlantic and the associated currents, described based on their volume transports. The main results indicate that the model is capable of representing realistically the vertical structure of the main currents and the associated water masses for the study region. In the equatorial portion of the subtropical gyre the model shows, for example, the southward zonal migration of the South Equatorial Current bifurcation with the increase of depth. According to the model and for the Tropical Water level, the bifurcation occurs between 9ºS-15ºS, moving to 25ºS at the level of the South Atlantic Central Water and between 25ºS-30ºS at the level of the Antarctic Intermediate Water. The North Atlantic Deep Water, which is part of the thermohaline circulation, is represented in the model with a net southward transport between 15 Sv and 20 Sv for the region of study and is in agreement with the literature values.

OCCAM; NODC; ocean circulation model; termohaline fields; South Atlantic; Tropical Water; South Atlantic Central Water; Antarctic Intermediate Water; North Atlantic Deep Water


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