Simulation of thermal effects due to different amounts of urban vegetation within the built-up area of Beijing, China

Urban heat islands (UHI) are a common phenomenon in most cities, and one of the most effective ways to mitigate UHI negative effects is with urban vegetation. This paper uses the mono-window algorithm for retrieving land surface temperature (LST) based on remote-sensing data, and simulates thermal effects in five situations, using different amounts of urban vegetation within the built-up area of Beijing. Our analyses indicated that the computed Near Surface Air Temperature (NSAT) of the current situation (25 July 2005) was 295.86K at 02:47 which is comparable to the real observed mean NSAT (296K) at that time. When all urban vegetation was removed, the mean LST and NSAT increased by 1.95K and 0.92K compared to the current situation. In addition, the mean NDVI (normalized difference vegetation index) increased to 0.22-0.42, while the mean NSAT decreased to 294.98-293.08K, which is close to a temperature comfortable to humans (295-293K) in that area. Our work should provide information for the government of Beijing and the public on the importance of urban vegetation in counteracting effects of UHI during urban land use and management projects.