The Algorithms of Urban Sprawl Dynamics on Surface Temperature Characteristics of Greater Port Harcourt Region, Using Remote Sensing- GIS Approach

Urbanization has global notable alteration on thermal, radiative, moisture and aerodynamic features of the landscape, which adversely affects the surface energy balance within the atmosphere. These alterations can propel a higher air and surface temperature of the urban centres when compared with the surrounding environment which is typically termed as urban heat island. In this study GIS and remote sensing were used to evaluate urban sprawl variation on surface temperature in Greater Port Harcourt. Landsat Thermatic Mapper (TM), Enhanced Thermatic Mapper plus (ETM+) and Landsat 8 Operational Land Image (OLI) images of 1986, 2000 and 2018 sequentially were adopted. The maximum likelihood algorithm classifiers were used in generating the land use land cover. Three land use land cover were generated and they are; vegetation cover, built up area and waterbodies. The normalized difference vegetation index (NDVI) was calculated using near infrared (Band 5) and Red (Band4) bands. Land surface temperature data were acquired through the landsat infrared thermal bands for the three years and the relationship between NDVI and land surface temperature was analysed. The result of this study showed that there is a great decrease in the natural environment and an increase in developed environment from 1986 to 2018. The GIS analysis showed that built up area has 629.73% increase within the study period while the maximum surface temperature has risen with 7oC from 1986 to 2018. If the increase in built up area still prevails in the study area as mentioned above surface temperature will be on the high side and this may bring about urban heat island. Hence, growing of trees and vegetation in and around the study area should be encouraged so as to reduce the rise in surface temperature of the land cover in the greater Port Harcourt.

Keywords: Urban growth, landcover, thermal characteristics, surface temperature, land use.