Evaluation of Greenery and Thermal Environment using Remote Sensing Data

In urban areas, the Urban Heat Island (UHI) phenomenon—characterized by significantly higher air temperatures in city centers compared to surrounding suburban areas— has become increasingly evident. This phenomenon is primarily attributed to the intensification of anthropogenic heat emissions, the artificialization of land cover, and the densification of urban morphology. Fukuoka City, a representative regional city in Japan, is no exception to this trend. This study aims to quantitatively evaluate the impact of vegetation and land use/land cover on the urban thermal environment of Fukuoka City by utilizing satellite-based remote sensing. Specifically, this study visualizes land use and land cover (LULC), land surface temperature (LST), and the Normalized Difference Vegetation Index (NDVI) in order to assess the relationship between vegetation coverage and urban thermal conditions. According to the analysis, urban areas in Fukuoka City are characterized by a high ratio of artificial structures, where regions with elevated LST are concentrated and NDVI values are notably low. Artificial surfaces exhibit low NDVI values and a wide range of LST, whereas green spaces show higher NDVI values and a narrower LST range. Furthermore, there is a clear inverse correlation between NDVI and LST: as NDVI increases, LST tends to decrease. These findings indicate that the presence of vegetation has a significant mitigating effect on the rise of LST. The results indicate elevated land surface temperatures throughout Fukuoka City, highlighting the urgent need for improvements in the context of sustainable urban planning and environmental policy. Enhancing vegetation, even within dense urban areas, is shown to be an effective measure for mitigating urban thermal environment.