A two-mode numerical model with applications to coastal upwelling

A first picture of the Agulhas current is obtained from data of the Quasi synoptic Agulhas current cruise of March 1969. Reinterpretation of other hydrographic data was possible in the light of the 1969 cruise and the information obtained from satellite tracked buoys. For the 1969 cruise acceleration potential diagrams on various sigma-t levels are discussed and indicate that certain features in the current are of such a scale (length and time) that only closely spaced synoptic stations will show them. Of special interest are the following features: two main supplies to the current; a region of dynamical upwelling between East London and Port Elizabeth; the region where the eastward (retroflection); the interaction with the South East Atlantic ocean; the planetary waves in the Agulhas return current over and east of the Agulhas plateau. Volume flux calculations (reference 1100m.) show that the two supplies to the Agulhas current could be estimated at 15 sverdrups each. The main part of the current turns back into the South West Indian ocean. An amount of roughly 5 sverdrups was lost East Atlantic. Property distributions although difficult to interpret, were used to construct the acceleration potential diagrams as the contouring of these diagrams was not always obvious. For a more detailed discussion of the combined data the current system was divided into areas. These areas are: Source area (including the inflow south of Durban and the countercurrent at Durban; Dynamical upwelling region; Mixing and retroflection area; Planetary wave region.

Grantor dc:publisher.institution

Department of Oceanography

Year dc:date.issued

1981

Author dc:creator

• Van Foreest, Dirk

Advisor dc:contributor.advisor

• Harris, T F W

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/16988

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/16988