Satellite Remote Sensing of the Urban Heat Island (UHI) Effect in Johannesburg
Hardy, Caroline H.; Nel, Andre L.
University of Johannesburg, SOUTH AFRICA

The objective of this study is to use Earth Observation data to study the Urban Heat Island (UHI) effect in South Africa; where the primary focus area of this study is Johannesburg. The UHI effect describes urban areas that exhibit temperatures that are warmer than that of surrounding areas. The UHI effect is strongest in densely populated urban areas and areas that have low levels of vegetative cover. With over 10 million trees, Johannesburg is often considered to be an urban forest. Many of Johannesburg's trees can can be found in private gardens, however vegetation levels vary across Johannesburg's residential suburbs and townships. Communities with high levels of vegetation benefit from cooling due to evo-transpirative processes and thus exhibit weaker UHI effects; while their impoverished counterparts are not so fortunate. Multi-temporal, multi-spectral remotely sensed satellite data from multiple sensors (such as AATSR, ASTER and Landsat) has provided us with the opportunity to perform a spatio-temporal investigation into the spatial variability and the trend in the UHI effect over various established and rapidly urbanizing residential regions in Johannesburg.