Analysis of spatio-temporal rainfall trends across southern African biomes between 1981 and 2016

Abstract

Southern African biomes experience significant changes in the distribution of rainfall that are linked to El Niño–Southern Oscillation. As such, an understanding of the spatio-temporal rainfall trends is key in predicting rainfall patterns as well as validation of climate change projections. Currently, the available information on rainfall trends in southern Africa is scanty with most studies focusing either on the spatial or the temporal dimension at localised levels. The novelty of this study is its regional aspect (i.e. all of southern African arid and semi-arid biomes) and the simultaneous integration of space and time in rainfall trend analysis through the use of space time rainfall cube. In this study, we simultaneously examined spatial and temporal rainfall trends based on the space-time rainfall cube derived from 1981 to 2016 CHIRPS satellite rainfall data. The space time rainfall trend analysis revealed a significant (P < 0.05) decrease of rainfall across most biomes particularly in the northern parts of the savanna biome and southwestern biomes (i.e. karoo, desert and fynbos). Statistically significant (P < 0.05) rainfall increase was observed in the central parts of the region mostly within the savanna biome. In terms of the magnitude of rainfall change, some of the areas experienced as much as 12 mm rainfall decrease in the mean annual rainfall while others recorded an increase of 14 mm. Our results provide baseline information for climate change adaptation and ecosystem conservation.