Dynamics of surface urban biophysical compositions and its impact on land surface thermal field

Abstract

Urban heat effects over Abeokuta city, Nigeria have raised interests by relevant scientific communities owing to the recent infrastructural and economic growth of the area. In this paper, the surface temperatures and land surface biophysical types retrieved from Landsat TM, and ETM+images of Abeokuta city for 1984, 2003 and 2014 were analyzed. The images acquired were classified into appropriate land cover types using supervised classification schemes and a change detection analysis was carried out on the classified imageries using land change modeller (LCM) to evaluate the extent of modification of surface features. A quantitative approach was used to explore the relationships among temperature, surface biophysical components and spectral indices. Results showed that impervious surface and water areas were found to be correlated positively with high temperatures. Conversely, vegetated areas and bare surfaces correlated positively with mid temperature zones. The overall metrics error between the regression-modeled LST and the retrieved LST for the study area is quite low, between 2.63 °C for root mean square error (RMSE) and 2.17 °C for mean absolute error (MAE). This study concluded that, areas with increasing built-up surfaces and surface reflectivity will bring about LST rise, and consequently leads to urban heat island development.