IN-SITU SURFACE TEMPERATURE AND THERMAL INFRARED SATELLITE DATA COLLECTION FOR HEAT ISLAND EVALUATION AND DATA COMPARISON IN AN URBAN AREA IN SOUTHWEST NIGERIA

Abstract

Urban Heat Island (UHI), which is due to differential cooling and heating of land surfaces, can increase the environmental and social vulnerabilities in an urban area. This study validated ground-based surface temperature from the digital infrared thermometer and thermal infrared satellite data to assess heat islands in Ibadan Metropolis, Nigeria. The study employed a single-channel algorithm method (SCA) to retrieve land surface temperature (LST), an important factor in global climate change, vegetation growth, and glacier. This was derived from the thermal band of Landsat-8. The results indicate that the mean surface temperatures derived from Landsat imageries during the study period differ from ground-based measurements in all the sample locations. Satellite-based LST over different locations had a range reading between 26.05 ºC and 29.28 ºC, while ground-based LST over the various communities ranged between 30.04ºC and 32.57ºC. Validation of satellite LST against ground-based LST data for each site yielded an average RMSE of between 3.69 and 5.56. The LSTs estimated for different sites are positively correlated between the two methods, with a correlation coefficient (r) between 0.87 and 0.40.
There is a problem with the accuracy of temperature data derived from satellite images, and these problems vary for many reasons.