Spatial and Temporal Analysis of Urban Heat Island Effects in College of Science and Technology

Abstract

The phenomenon of Urban Heat Island (UHI) which is defined by increasing surface and air temperature in urban areas compared to surrounding areas is a growing concern due to several impacts. These includes heat stress, increase in energy consumption, degradation in environmental quality among others. Understanding the spatial and temporal variation of UHI will be useful in the planning of urban infrastructures. Therefore, the aim of the present study is to analyze the spatial and temporal variations of UHI in the College of Science and Technology (CST) from 2013 to 2023. The study analyzed the changes in Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI) and Normalized Difference Built-up Index (NDBI). Air temperature was recorded at multiple locations at 8 AM, 12 PM and 4 PM over four days to examine the variation in air temperature due to the type of ground surface using handheld thermometer. The findings of the study show that there was a 3.5% increase in built-up area and a 17.14% decrease in vegetation cover during the 10-year period. The lower and upper limit of LST decreased over the decade which may be attributed to different seasonal timing. Normalized LST (NLST) analysis revealed that UHI zones expanded from 46.7% in 2013 to 53.3% in 2023.  A weakening negative correlation between NDVI and LST (from -0.65 to -0.52) and a strengthening positive correlation between NDBI and LST (from 0.58 to 0.60) were observed, highlighting the cooling effect of vegetation and the heat retention of built-up surfaces. Air temperature patterns showed consistently higher values over built-up areas and cooler, more stable temperatures over vegetated zones. The findings provide valuable insight into the extent of the UHI effect in CST.