A Modelling Study of Coastal Upwelling Driven by Wind and Meanders of the Brazil Current

A numerical model is used to investigate coastal upwelling in the South Brazil Bight. The wind in the area is predominantly from the northeast, especially in summer, which is upwelling favorable. Reversals of the wind direction are frequent and intense during the winter, due to the passage of fronta...

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Bibliographic Details
Published in:Journal of coastal research 2004-07, Vol.20 (3), p.662-671
Main Authors: Castelao, Renato M., Campos, Edmo J. D., Miller, Jerry L.
Format: Article
Language:English
Subjects:
Bays
Brazil
Brazil Current
Coastal oceanography
Coastal oceanography, estuaries. Regional oceanography
coastal upwelling
Coasts
cyclonic meander
Earth, ocean, space
Exact sciences and technology
External geophysics
Flow velocity
Ocean circulation models
Ocean currents
Oceans
Physics of the oceans
RESEARCH PAPERS
Salinity
Sea transportation
Sea water
shelf dynamics
South Brazil Bight
Upwelling water
wind-driven circulation
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Summary:A numerical model is used to investigate coastal upwelling in the South Brazil Bight. The wind in the area is predominantly from the northeast, especially in summer, which is upwelling favorable. Reversals of the wind direction are frequent and intense during the winter, due to the passage of frontal systems. The offshore circulation is dominated by the Brazil Current, which flows southward meandering around the 200 m isobath. Significant shelf-break upwelling has being associated with Brazil Current cyclonic meanders. To assess the relative importance of the two processes in the pumping of South Atlantic Central Water (SACW) onto the continental shelf, three cases are analyzed: (1) wind-driven upwelling; (2) upwelling induced by Brazil Current meanders and (3) both effects acting together. The results show that in the coastal area upwelling/downwelling is mainly caused by the wind, whereas the cyclonic meanders of the Brazil Current are the dominant mechanism in the generation of vertical velocities over the shelf break and slope. This meander-induced upward motion brings the SACW to shallower depths, where it is influenced by the wind. In this situation, when both effects act together, the SACW penetrates all the way to the coast.
ISSN:0749-0208
1551-5036
DOI:10.2112/1551-5036(2004)20[662:AMSOCU]2.0.CO;2