Spatial analysis of urban expansion, land-use dynamics and its effects on land surface temperature in Oyo town, Southwestern Nigeria

Abstract

This paper assessed the expansion of land use and land cover that occurred in Oyo State, Southwestern Nigeria, over a period of thirty-year. This was to assess urban expansion, landuse dynamics and their effects on land surface temperature in the area. The study used four multi-date imageries of the area. Landsat 7 ETM + , 1990, 2000, 2012, and Landsat 8 OLI/TIR, 2021 were collected from the United States Geological Survey (USGS) website were used. The ArcGIS 10.1 environment was utilised to clip the area of interest, and ERDAS Imagine remote sensing software was employed to efficiently improve and categorise the images. The images were then divided into five major: cultivation, built-up area, vegetation, water body, and bare soil using a maximum likelihood supervised classification algorithm. These categories were then utilised to conduct time series analysis or change detection analysis.Results of this study revealed that the built-up area has changed over the preceding three decades because of urban expansion. The built-up area increased from 19.83 km2 to 35.67 km2 in 2012 and 44.84 km2 in 2021, indicating increases of 14.93% to 79.87% and 25.71%, respectively, whereas the vegetative land cover decreased from -0.11% to -3.01 48% and 12.75% during the study period. Findings revealed that anthropogenic factors including urbanisation and agricultural expansion, have significantly altered the surface and atmospheric characteristics of the study area, causing a variety of heat patterns within the area. The built-up area had average temperatures between 35.05 °C and 36.16 °C between 1990 and 2021, which indicated a higher temperature with evidence of an urban heat island.This study concludes that the city’s land surface temperature is rising and that the expanding built-up area’s density and a corresponding decline in vegetation over time significantly impact it. Therefore, the study suggests cultivating and maintaining trees, promoting green environment,, public awareness, campaigns and education on actions that aggravate high temperatures are also required.