Evaluating the impact of land cover change on land surface temperatures in Kira Municipality

Abstract

Changes in Land Surface Temperature (LST) have often been linked to changes in land cover. There is however, lack of adequate accurate information regarding the impact of land cover change on LST especially in developing countries where there is limited or no information regarding LST measurements due to a small number of well-equipped weather stations. This study therefore aimed at assessing the impact of land cover change on LST in Kira municipality which is the most densely populated municipality in Wakiso district, Uganda with a population density of 3,292 people/km2. This high population density puts tremendous pressure on vegetation cover as it is replaced by impervious surfaces like roads and buildings that service the population. The research adopted the Object Based Image Analysis (OBIA) in classifying atmospherically corrected Landsat 7 images into three land cover classes (Vegetation, Water, and Built-up). The images were acquired during the months of January and February, when the study area experiences a dry season, for the years 2003, 2008, 2014 and 2019. LST was derived from the thermal band of the Landsat level 2 image. The results showed that there was a general decrease in vegetation cover and increase in built-up area from 2003 to 2019. The percentage coverage of built-up area increased from 3.25% in 2003 to 25.73% in 2019 while percentage vegetation cover reduced from 95.86% to 73.29% and water coverage remained under 1% during the study period. These land cover changes led to a general increase in mean LST from 24.68 ℃ in 2003 to 31.64 in 2019. The increase in LST can mainly be attributed to the replacement of vegetation cover that has a cooling effect with non-transpiring surfaces like buildings and roads that service the growing population in the study area. The research recommends that further studies should explore the impacts that changes in LST have on ecosystems in urban environments including its effects on microorganisms in the soil. Furthermore, the study also recommends further studies to explore the relationship between LST and the internal properties of earth’s surface.