‘n Ruimtelike-analitiese ondersoek na seisoenale reënval- en temperatuurpatrone oor suidelike Afrika
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Van der Walt, Adriaan Johannes
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University of the Free State
Abstract
Showing abstract in English
English: 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.