Assessment of the thermal response of variations in land surface around an urban area

The ancient city of Ibadan has experienced major development and this development has led to modifications of the land surface over the years. This study assessed the changes that have occurred in the Land Use Land Cover (LULC) of Ibadan city using satellite image from Landsat covering 1984, 2000 and 2016. Supervised classification scheme was done using the maximum likelihood classifier for classifying the images. The extent of change of the LULC classes was performed on the classified images using Land Change Modeller (LCM). The implication of the change in LULC on Land Surface Temperature (LST) and related indices was assessed. Over a period of 32 years (1984–2016), the area coverage of the built-up region of Ibadan increased from 11.23 to 54.64 hectares in thousands with a net change of 8%. Thick vegetation was identified as the major contributor to the increase in the built-up area thus indicating urban encroachment. The implication of this was observed in thermal hotspots distribution and increase in the average LST over Ibadan as there was a decrease in vegetated surfaces that dampen the LST and an increase in the impervious surface revealed by the impervious and built-up index. In general, this study showed the capability of impervious surface indices in depicting the variations in land use land cover around a region, majorly urban sprawl. Furthermore, the evaluation of the spectral indices showed Urban Index (UI) as the best predictor LST.