Determination of Urban Thermal Characteristics on an Urban/Rural Land Cover Gradient Using Remotely Sensed Data

Abstract

The transformation from natural to impervious surfaces in an urbanization process and the urban heat island (UHI) phenomenon is known to significantly compromise urban environmental quality and has been linked to climate change and associated impacts. Whereas the existence of UHI is common knowledge, the implication of urban land use land cover (LULC) gradient on intra-urban thermal characteristics is often poorly understood. A recent proliferation of remotely sensed datasets offer great potential in understanding the relationship  between urban LULCs and their respective thermal characteristics, a critical basis for urban environmental  management and designing climate change mitigation measures. This study explores the potential of  multispectral remotely sensed dataset in determining the influence of rural/urban LULC gradient on urban  thermal characteristics. A rectangular eleven band Landsat 8 image subset was delineated from the central  business district to the rural periphery and classified into most dominant LULCs and a corresponding Landsat 8 thermal layer used to determine the LULCs thermal characteristics. Digitized point data was used to  determine differences in land surface temperature (LST) over gradient's LULC types. Results showed that  there was varied contribution of LULCs to the LST. As expected, the density of built up surfaces and LST  decreased towards the city’s periphery while a decline in vegetation density from the periphery led to an  increase in LST. These results provide valuable insights into the value of remotely sensed datasets in  understanding the implication of intra-urban LULC gradient on LST characteristics. Specifically, the study  demonstrates the value of remotely sensed data as aids to sustainable urban environmental planning.