ASSESSING URBAN HEAT ISLAND (UHI) IN IFE CENTRAL LGA, OSUN STATE, USING MULTI-TEMPORAL LANDSAT THERMAL INFRARED IMAGERY

Abstract

Urban Heat Island (UHI) phenomenon is becoming an increasing environmental issue in areas that are 
urbanizing quickly, as it exacerbates local temperature rises and impacts human health and the stability of 
ecosystems. This study aimed to assess and map UHI intensity in Ife Central Local Government Area, 
Osun State, using multi-temporal Landsat thermal infrared imagery. The specific objectives were to (i) 
assess temporal changes in land cover types between 2015 and 2025, (ii) evaluate UHI intensity over the 
same period, and (iii) determine the relationship between selected spectral indices (NDVI, NDBI, NDBSI, 
NDWI, and NDRI) and Land Surface Temperature (LST) to identify the key drivers of UHI. Landsat 8 and 
9 OLI/TIRS images and the Local Government Area boundary were processed and analyzed using 
radiometric calibration, atmospheric correction, supervised land cover classification, NDVI-based 
emissivity estimation, LST retrieval, and UHI calculation. Correlation analyses between LST and spectral 
indices were also performed. The results revealed the land cover types in the study area include built-up, 
vegetation, water bodies, bare land, and rocky surfaces. The results further showed that urban areas 
increased from 16.4% to 26.1%, while vegetation cover declined from 70.2% to 65.4% between 2015 and 
2025. UHI intensity also intensified, with minimum surface temperatures rising from 25.2 °C to 27.3 °C 
and maximum temperatures from 31.1 °C to 33.9 °C. Correlation analysis indicated that NDBI ((113.95x 
+ 19.28) and NDRI (149.38x + 13.208) had substantial positive relationships with LST (R² = 0.52 and 
0.66, respectively), while NDVI (-32.236x + 17.072), NDWI (-33.535x + 5.287), and NDBSI (-32.236x + 
17.072) were weakly negatively correlated (R² < 0.02), highlighting built-up and rocky surfaces as the 
main contributors to UHI. The study recommends the adoption of sustainable urban planning measures 
such as expanding green infrastructure, increasing vegetation cover, and promoting heat-mitigating 
materials to reduce UHI effects and enhance environmental resilience in the area.