Equilibrium dynamics of the Benguela system : a numerical modelling approach

• Main Author: Veitch, Jennifer Anne
• Other Authors: Shillington, Frank
• Format: Doctoral Thesis
• Language: English
• Published: University of Cape Town 2015
• Subjects: Oceanography
• Online Access: http://hdl.handle.net/11427/12153

Includes abstract. === Includes bibliographical references (p. 237-255). === The Regional Ocean Modelling System (ROMS) is used to systematically investigate equilibrium conditions and seasonal variations of the Benguela system, including both the large-scale flow regime as well as the coastal upswelling regime. A shelf-edge poleward flow exists in the northern Benguela region and is driven primarily by the wind-stress curl via the Sverdup relation. As such, it is strongly seasonal and is most intense during spring and summer when the wind-stress curl is most negative. The poleward flow deepens as it moves southward and between 25-27° much of it veers offshore due to the nature of of the wind-stress curl. In the mean state, the Benguela Current is characterized by two streams: the more inshore stream is topographically controlled and follows the run of the shelf-edge. The offshore stream is driven by nonlinear reactions of passing Aghulas rings and eddies and does not have a striking seasonal signal. The model simulates all seven of the major upswelling cells within its domain.