Abstract:
Urban heat island (UHI) has been mostly observed as urbanization accelerated. UHI are closely affected by land use types and their landscape pattern, population, and geological conditions (altitude). Land surface temperature (LST) and land use types of Guangzhou were retrieved by using Landsat-8 images, and altitude was extracted by using Digital Elevation Model (DEM). Landscape indicators of different towns and streets were calculated based on the landscape ecological methodologies, as population-related data collated from statistical yearbook. This paper focused on the impacting mechanism of UHI from the three aspects including population, altitude, and changes of land use types and their landscape patterns exemplified by Guangzhou. We founded that LST was significantly correlated with population density, altitude and proportions of different land use types. Moreover, LST was critically affected by three key factors such as ecological-land cover, constructed-land cover and altitude as stepwise regression analysis used. It indicated that altitude should be taken into consideration when affecting factors of UHI discussed. Also, increasing proportion of constructed-land cover would strengthen the intensity of UHI, while increasing proportion of ecological-land cover would decrease the intensity of UHI. Except for some landscape indicators, most of landscape indicators of different landscape indicators were significantly correlated with LST. Stepwise regression analysis showed that LST was mainly controlled by aggregation index (AI), edge density (ED) and landscape division index (DIVISION) of constructed-land use type and also obviously affected by DIVISION of forest. As urban planning in the future, a better proportion and spatial pattern of different land use types (especially forest and constructed land use types) should be comprehensively and systematically taken into consideration in order to mitigate the UHI effect, as topological factors such as altitude should betaken into consideration.