Satellite image analysis of thermal comfort for a sustainable urban ecology of Winneba, Ghana

To mitigate thermal heat effects for a sustainable urban living environment through planning and interventions, studies on land surface temperature (LST) in urban settings are crucial. Thus, the relationship between LST and surface landscape must be established to accurately assess the impacts of surface temperature changes for planning purposes. This will help gain knowledge about the spatial concentration of the heat effects and to design practical needs of urban planning. The study aimed to analyse and reveal the spatial dynamics of LST and its statistical relationship with two normalised satellite indices using Landsat satellite data. The Landsat-derived LST is validated using the MODIS surface temperature data. It also mapped the heat spots (HS) and evaluated the ecological evaluation index and thermal comfort using the thermal field variance index (TFVI). The results showed spatial variation in LST even within the built-up areas due to heterogeneity in the surface characteristics. Thus, localised heat islands (HIs) exist within short distances. The analysis established an inverse correlation for LST-NDVI and a direct correlation for LST-NDBI. The vegetation and water surfaces served as important heat reduction sinks while heavily built-up areas and the hardened-clayey bare surfaces served as heat-enhancing sources. More than half (52.80%) of the study area enjoys an excellent (48.57%) and good (4.23%) ecological evaluation index, indicating excellent to good thermal comfort. Much of these areas are in the urban periphery. Also, more than one-third (38.96%) enjoy the worst (34.85%) and worse (4.11%) ecological evaluation index and thus high thermal discomfort. Identifying these HS areas and evaluating the thermal comfort will help the planners and decision-makers to fully evaluate the thermal consequences of different landuse or land development scenarios and therefore improve the scientific basis of future planning and regulations.