An ADCP study of subtidal scale density-driven exchange in Saldanha Bay, South Africa

An ADCP and water-column temperature study was conducted to determine the circulation aspect of subtidal-scale, density-driven exchange in Saldanha Bay, South Africa. Density-driven exchange conditions develop in response to synoptic-scale wind events in the southern Benguela region, even under light (<5m s-') wind conditions. During a density-driven exchange event, directionally opposing bi-level flow, similar to an estuarine system, develops in response to remote upwelling-favourable winds. The bi-level flow component occurs in two distinct bands, bayward at 0-9m height from bottom and seaward 15-20m height off bottom, and is very sensitive to changes in wind forcing. Observations of current behaviour are added to the four-phase conceptual model of density-driven exchange developed by Monteiro and Largier (1999). In addition, estimates of bay flushing based on ADCP current velocities and the four-phase conceptual model are calculated and implications of shelf water influx into Saldanha Bay are discussed.

Grantor dc:publisher.institution

Department of Oceanography

Year dc:date.issued

2003

Author dc:creator

• Stewart, Helen Frances

Advisors dc:contributor.advisor

• Monteiro, Pedro M S
• Waldron, Howard
• Brundrit, Geoff

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/6455

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/6455