Trend Analysis of Climate Variability over the West Bank - East London Area, South Africa (1975-2011)

In recent years, climate change has received considerable attention by the scientific community at different scales concerning its potential impacts on Earth system processes. This study focused at local scale by analysing trends in rainfall and temperature data for the West Bank–East London area in South Africa, spanning 36 years from 1975–2011. Sen’s and Man-Kendall non-parametric tests were performed on derived mean observed rainfall and temperature data to establish trends for monthly, seasonal, annual, and 30 year (1975–2005 and 1980–2011) climatic regimes. Results revealed that, 1977 recorded the highest annual rainfall (2272.9 mm) while the month of August received the highest total rainfall (493.8 mm) in 2002, whereas it never had rain in 1995. Seasonal and annual rainfall showed statistically no significant trend (at a = 0.10) while the magnitude of change varied between 1.87 mm (January) and -1.67 mm (September) across the study period. Rainfall decreased by 13.99 mm within the two climatic regimes. On the other hand, maximum and minimum annual mean temperature experienced an increasingly statistically significant trend (at a < 0.05) at 95% confidence level. February recorded the highest mean monthly temperature (21.8 °C) while July with the lowest (12.6 °C). Seasonal mean maximum temperature trends were statistically not significant (a = 0.10) while autumn minimum temperatures revealed a statistically significant trend (at a < 0.1). However, the period 1990-1999 predominantly experienced numerous extreme events. The seasonal trends showed substantial variability across the months and years during the study period. The significance of these findings lies in the linkage of rainfall and temperature to climate change and its potential impacts on vegetation in particular and changes in the ecology in general.