Urban Land Surface Temperature and Vegetation Correlation in the Kumasi Metropolis

Abstract

Urban heat is considered as a worrying issue in cities because of the unbearable feelings associated with heat especially on sunny days. Urban heat is not as a result of any one time event but a chain of processes associated with land use activities such as infrastructure development that replaces the green vegetation. This paper investigated how land surface temperature has changed in the Kumasi Metropolis in 10 years from an environment of low temperature to much warmer land surface temperature due to the loss of trees in the city. The objectives of the study were to assess the extent of Land Surface Temperature (LST) in the metropolis, determine the kind of correlation that exist between Land Surface Temperate and vegetation health and examine the extent to which vegetation has influenced the city temperature. Multiple methods were used to calculate Land Surface Temperature (LST) such as converting the digital numbers of Landsat 2009, 2015 and 2019 images to radiance, top of brightness temperature and at-sensor brightness temperature using the Plank’s inverse function. NDVI analysis was done by subtracting the near infrared bands from the red band, divided by addition of the near infrared band to the red Band. Study results showed a linear increase in LST from an average of about 18°C to 31°C. The NDVI result showed decline in vegetation cover as such the correlation analysis was a negative correlation showing places of high temperature had minimal vegetation cover while places of low temperature had more vegetation cover.