Simulating and forecasting southern Africa's ocean


Models allow us to virtually 'observe' the ocean in a manner that is temporally and spatially cohesive. Pseudo-synoptic 'snapshots' of model-derived ocean processes are impossible to achieve with either satellite or in situ observations. Models can therefore provide improved insight into the evolution of ocean features that are highly dynamic.

The figure shows SSTs from a HYCOM ocean model simulation of the Agulhas Current that aims to be as realistic as possible.

One ocean modelling approach is to numerically reproduce the ocean as realistically as possible. Even if it were possible to perfectly simulate a realistic ocean, it would be no easier to understand. A second kind of approach is to simplify ocean models in order to obtain conclusive answers to questions on the generation and fate of ocean processes. Research activities, based on both modelling approaches, are essential if we are to improve our understanding of the dynamics of important ocean features so that we can anticipate how they might evolve in any of the possible climate change scenarios.

The figure shows SSTs from a ROMS simulation that 'removes' the influence of the Agulhas on the Benguela system, by constructing a virtual dam off the west coast of South Africa.

The use of ocean models in South Africa as a tool for research has increased significantly in the last decade and continues to do so as local expertise develops. Currently, research-based ocean modelling activities are primarily associated with UCT and, to some extent, with the CSIR.

continental shelf continental shelf
The figures above show the usefulness of models in testing hypotheses. In this case, the continental shelf has been smoothed (left) in order to test its influence on the mean transport (right).