‘n Ruimtelike-analitiese ondersoek na seisoenale reënval- en temperatuurpatrone oor suidelike Afrika

Changes in climatic variability and extremes of weather and climate events have received increased attention in the last few years. Many studies have been done on climate trends, especially for precipitation and temperature, compared to the time before the issue of climate change became more prominent during the 1980s. Since then, one of the biggest motivations for such studies is to establish if and how global warming might have influenced the climate on a global as well as regional scale. Southern Africa is predominantly semi-arid region with generally a high inter-annual rainfall variability and pronounced seasonal cycle. Climate variability and long-term change thus pose serious challenges for southern Africa. The main aim for this study is to investigate the seasonal trends of rainfall and surface temperature from 1950 to 1999 and to compare these seasonal trends with yearly trends. Rainfall and temperature data of the 1 946 Quaternary catchments in South Africa, Swaziland and Lesotho were used as input data. Correlation coefficients were determined and mapped using Geographic Information Systems ArcMap. HotSpot analysis was used to calculate the Getis-Ord Gi* statistic (Z score) for each feature in the data set. Results show more pronounced trends in rainfall and surface temperature during the different seasons.