Circulation on the western South Atlantic continental shelf 1. Numerical process studies on buoyancy

I. D. Soares, Vassiliki H Kourafalou, T. N. Lee

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Buoyancy-driven currents are investigated in the western South Atlantic Ocean, where a major river plume, La Plata, interacts with a minor one, Patos Lagoon. A series of simulations were performed with a three-dimensional, free-surface numerical model, to better understand the processes which control both plumes evolution and their interaction. The simulations are focused on the importance of turbulent mixing to the evolution of the La Plata plume and its downshelf penetration toward the Patos Lagoon. Satellite observations and historical data show that the La Plata plume has a tendency to expand along the river southern margin, before it turns north in the direction of coastal trapped waves propagation. Our results, on the other hand, show that in the absence of the tides and the wind, this plume tends to leave the estuary attached to its northern margin (downstream), unless the model parameters are tuned to produce unrealistically high turbulent mixing. We then address the role of each parameter that controls mixing, and show that by tuning the model parameters we can get plumes similar to those observed in nature. However, the plumes produced in the experiments with excessively high mixing parameters showed unbounded southward (upstream) expansion. By introducing the tides we show that the plumes produced in the presence of tidal stirring, and normally set mixing parameters, are more realistic, suggesting that tidal stirring is more effective than artificially tuned turbulent mixing on causing the plume lateral expansion.

Original languageEnglish (US)
Article numberC04002
JournalJournal of Geophysical Research C: Oceans
Volume112
Issue number4
DOIs
StatePublished - Apr 8 2007

Fingerprint

continental shelves
Buoyancy
buoyancy
plumes
continental shelf
plume
turbulent mixing
Tides
lagoons
Rivers
stirring
tides
lagoon
rivers
tide
margins
Estuaries
trapped wave
Wave propagation
river plume

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Atmospheric Science
  • Astronomy and Astrophysics
  • Oceanography

Cite this

Circulation on the western South Atlantic continental shelf 1. Numerical process studies on buoyancy. / Soares, I. D.; Kourafalou, Vassiliki H; Lee, T. N.

In: Journal of Geophysical Research C: Oceans, Vol. 112, No. 4, C04002, 08.04.2007.

Research output: Contribution to journalArticle

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