Monitoring thermal environment deterioration and its dynamic response to urban expansion in Wuhan, China

Abstract

Understanding how urban heat island (UHI) effect responds to urbanization is of great significance to develop appropriate UHI mitigation measures. However, the dynamic response of thermal environment to urban expansion is still less discussed. In this study, the spatiotemporal variation of thermal characteristics and its dynamic response to urbanization was monitored at the pixel level in 1987, 1996, 2007 and 2016 in Wuhan, China based on multi-temporal remotely sensed images. The results indicate that Wuhan experienced significant thermal deterioration during the 29-year period, which was largely attributed to the rapid urbanization from 1996 to 2007. Due to the high spatial heterogeneity of urban development, the thermal characteristic variation did not always spatially correspond to urbanization process. The urbanization dynamics alone can explain only 14.84% ~ 36.37% of the spatiotemporal variation in thermal environment throughout the study area. Nevertheless, the thermally deteriorated areas had good spatial consistence with the rapidly developed areas in all cases, suggesting that urban development could better explain the dynamic characteristics of thermal environment in more rapidly urbanized areas (with the R2 values of 0.7013–0.9989). An obvious “context effect” was detected during the dynamic influence of urban development on thermal environment variation. Urban development based on the increase of construction density only strengthened UHI intensity, but contributed little to the spread of thermal environment deterioration. Urban expansion with amounts of newly expanded construction land should be responsible for thermal environment deterioration. These findings provide detailed information and sound evidence to adjust urban planning options accordingly to improve thermal environment.