Barker, C. H.Van der Walt, Adriaan Johannes2015-08-192015-08-192014-07http://hdl.handle.net/11660/931English: 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.Afrikaans: Variasies in klimaatsveranderlikheid en uiterstes van die weer en klimaat ontvang meer aandag oor die laaste paar jaar. Baie studies oor die afgelope dekades is gedoen oor die klimaatneigings, veral vir reënval en oppervlaktemperatuur, in vergelyking met die 1980’s voor die kwessie van klimaatsverandering prominent geword het. Sedertdien, is een van die grootste motiverings vir sodanige studies om vas te stel of en hoe aardverwarming die klimaat op 'n globale sowel as plaaslike skaal kan beïnvloed. Suidelike Afrika is hoofsaaklik ‘n semi-droë streek met 'n algemene hoë inter-jaarlikse reënvalwisselvalligheid en seisoenale siklusse. Klimaatveranderlikheid en langtermynveranderinge is dus ernstige uitdagings vir Suidelike Afrika. Die hoofdoel van hierdie studie is om die seisoenale tendense van reënval en temperatuur te ondersoek vanaf 1950 tot 1999 en die seisoenale tendense met jaarlikse tendense te vergelyk. Reënval- en temperatuurdata van die 1 946 Kwaternêre opvanggebiede in Suid- Afrika, Swaziland en Lesotho is gebruik as inset data. Die korrelasiekoëffisiënte van elke Kwaternêre opvangsgebiede is bepaal. Met behulp van die Geografiese Inligtingstelsel ArcMap, is kaarte geproduseer deur gebruik te maak van die warmkol-analise ontledingsinstrument. Die warmkolanalise-instrument bereken die Getis - Ord Gi * statistiek vir elke waarde in die datastel. Resultate toon duidelike tendense ten opsigte van reënval en oppervlaktemperature binne die verskillende seisoene aan.afClimate variabilitySeasonal trendsQuaternary catchmentsCorrelation coefficientsGeographical Information SystemsHotSpot AnalysisClimate changeDissertation (M.Sc. (Geography))--University of the Free State, 2014DissertationUniversity of the Free State