Wind-driven mixed layer and coastal upwelling processes off the south coast of South Africa
Abstract:Most coastal mixed layer and upwelling investigations have concentrated on the more important fisheries regions situated on the west coasts of the continents, while this paper analyzes conditions on the zonally-orientated south coast of South Africa. Most of the data originate from a short measurement program in the southern summer of 1995, involving both CTD measurements from a small boat and data from a temperature array and coastal sea surface temperature (SST).
Limited mixed layer statistics are derived and yield results similar to those of Lentz (1992), although a lack of current measurements precludes any assessment of the Ekman drift. It is shown that the nature of the summer wind forcing is very different to the situation off the South African west coast, with wind variability occurring on much shorter time scales from 2 to 6 days: this has important consequences for plankton blooms and is a likely reason why production is not as efficient off this coast. Past results (Tilney et al., 1996) have shown the importance of coastal trapped waves at depth, but it is apparent that very different conditions occur near the surface.
It is found that the coastal SST is a very good monitor of wind-forced coastal upwelling conditions, probably because of the abrupt topography. Substantial baroclinic tidal signals are also apparent at times in the temperature measurements.
Document Type: Research Article
Publication date: 1999-07-01
More about this publication?
- The Journal of Marine Research publishes peer-reviewed research articles covering a broad array of topics in physical, biological and chemical oceanography. Articles that deal with processes, as well as those that report significant observations, are welcome. In the area of biology, studies involving coupling between ecological and physical processes are preferred over those that report systematics. Authors benefit from thorough reviews of their manuscripts, where an attempt is made to maximize clarity. The time between submission and publication is kept to a minimum; there is no page charge.
- Editorial Board
- Information for Authors
- Subscribe to this Title
- Ingenta Connect is not responsible for the content or availability of external websites