Seasonal different effects of land cover on urban heat island in Wuhan's metropolitan area

Urban sprawl increases impervious surfaces and decreases vegetation cover, which exacerbates the urban heat island phenomenon. In this study, we analyzed the spatiotemporal evolution law and determined the differences between urban heat islands in winter and summer. The Land Use Contribution Index introduced a new idea for studying the relationship between land cover and heat islands. We found that with urbanization, the area of heat islands increased in the winter and summer. However, heat island intensity varied greatly depending on the season among different land types. Specifically, rivers showed the characteristics of a warm winter and cool summer, which provided new strategies for improving the urban thermal environment. Heat island intensity change maps and land transfer maps were spatially superimposed to visualize how the intensity of the heat island of the land changes with the differences in the type of cover. The results indicated that the conversion of cultivated land into construction land was the main reason for changes in the land type, and the intensity of the heat island effect of most of these converted lands was enhanced. However, the proportion of enhancement decreased gradually.