Accessing the impact of urbanization on land surface temperature case study Kampala, Uganda

Abstract

Urbanization leads to the construction of various urban infrastructures in the city area for residency, transportation, industry, and other purposes, which causes major land use change. Urbanization has been linked to land surface temperature (LST) due to changes in land use and cover. It substantially affects Land Surface Temperature (LST) by unbalancing the surface energy budget. Higher LST in city areas decreases human thermal comfort for city dwellers and affects the urban environment and ecosystem. Therefore, a comprehensive investigation is needed to assess the impact of urbanization on the LST. This study aims to examine the impact of urbanization on LST in and around Kampala city, Uganda, through the use of RS and GIS techniques were used for this detailed investigation. The radiometrically corrected thermal infrared bands of the Landsat images of 2002,2010 and 2020 were used to retrieve land surface temperature while the Maximum Likelihood algorithm in QGIS Hannover using the Semi- Automatic Classification Plugin was used to generate a classified image for the three periods. Land surface temperature maps, land cover index maps, BDI were generated. The LST increased significantly from 2002 to 2010 with a decrease in 2020. Correlation analysis using Pearson’s Product Moment Method was carried out between land surface temperature and NDBI, BD. Built-up area increased within the same periods from 52.35% to 67.32% which could be attributed to anthropogenic activities. The land surface temperature distribution maps showed a more pronounced intensity in areas of significant built area than in areas covered by vegetation and waterbody. There was a positive correlation between LST and BDI, NDBI with NDBI proving to be a better predictor of land surface temperature. The study concluded that the nature of land use / land cover patterns in Kampala have impacted its land surface with a corresponding increase in land surface temperature. It is expected that as the city expands further, the magnitude of the land surface temperature will also increase thereby affecting the living conditions of the urban populace.