Modeling the Heat Island Intensity (HII) Based on Distance Diffusion and Typical Ground Feature Types in Beijing Downtown

Understanding the spatiotemporal evolution and the causes of the formation of urban heat island (UHI) is of great significance to ease the urban thermal environment and improve the comfortability for human settlement. The land surface temperature (LST) of Beijing downtown is retrieved based on Landsat thermal infrared images, and the LST is graded to obtain multi-grade heat island intensity (HII) for analyzing the evolution law and spatial pattern of UHI. The Beijing downtown was divided into 30 ring buffers, and the proportion of ground feature types and the information on HII in each ring buffer was analyzed. Also, the relationship between the influence factor and the HII is established based on the statistical data onto each ground feature type and the distance from the downtown. The results showed that the overall HII is increasing every year in Beijing downtown. The impervious surface has a great impact on the HII, the strength of HII becomes greater with the growth of impervious surface percentage (ISP). The strength of HII decreases gradually with the increasing distance from the center of the city.