New look at the weather

For the first time in South African history, daily weather forecasts are taking place outside of the South African Weather Service, thanks to a four-year WRC funded project.

The project, undertaken by members of the Meteorology at the University of Pretoria’s Department of Geography, Geoinformatics and Meteorology, has led to the establishment of a website where members of the public can view daily forecasts, up to four days in advance, over South Africa and the rest of the Southern African Developing Community.

The information is extracted from a so-called numerical weather prediction model, a complex computer program that simulates atmospheric behaviour and rainfall over southern Africa through the use of intricate mathematical equations.

The research team obtained a licence agreement for an existing model, known as C-CAM, which was originally developed by the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) Division of Atmospheric Research (AR), and adapted it to provide more accurate rainfall simulations over South Africa and the region. One of the main achievements of this project is the fact that the newly-improved model simulates rainfall events over the country more accurately than ever before.

“Rainfall is very difficult to simulate,” explains project leader Prof Hannes Rautenbach of the Meteorology Group. “Previous research indicates that regional-scale numerical models, in general, developed mostly in the US and Europe, tend to overestimate rainfall over South Africa by an average of as high as 400 mm a month. However, by adapting the CSIRO-AR model we have refined it to 10 mm to 20 mm a month in the C-CAM model.”

The groundwork has now also been laid for the development of the southern African region’s own numerical weather prediction model. To access the website, click on www.up.ac.za/academic/geog/meteo.