GIS-Based Determination of Urban Heat Island Profile of Kaduna Metropolis, Nigeria

Studies on Urban Heat Island (UHI) have become an important way to create sustainable and lively cities; it improves public health and enhances urban quality of life.  An increase in the level of Land Surface Temperature (LST) and a corresponding rise in the urban temperature as UHI among many cities of Nigeria brings about more outbreaks of heat related diseases.  The current research focused on the assessment of spatial patterns of LST and UHI in the Kaduna metropolis.  Land sat 8, operational land imager (OLI) imagery of April 2024 was used for the research.  Analysis was conducted through the determination of the Normalized Difference Vegetation Index (NDVI), vegetation density map, satellite brightness temperature, LST, and finally, UHI profile on ArcGIS 10.8 software.  Results on vegetation density revealed that areas with very low vegetation cover recorded the highest (44.86%) while those with moderate vegetation cover had the lowest (12.06%).  The findings also indicated that the highest (47.55%) percent of the study area experienced higher LST while only 8.93% experienced lower LST.  Results also show that most (37.43%) percent of the research area recorded a high (6.55oC) rate of UHI, 16.38% recorded about 8.5oC, while only 1.87% experienced a low UHI of 3.4oC.  Results of the regression analysis between NDVI and UHI indicated an inverse relationship between vegetation density and urban heat islands in such a way that, for every 1-unit increase in vegetation density, UHI decreases by ~19.63 units while the negative sign means more vegetation resulted in lower urban heat (cooling effect).  In conclusion, the study indicated that the western and heart of the metropolis had high UHI profiles while the eastern part of the area and other areas along the water bodies experienced lower UHI.  Based on these, the study recommends the provision of strategies such as plating trees which will help in reducing higher rate of heat, this is more especially during the hot and dry season.