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Comparison between summer and winter urban heat island of Beijing city

Urban heat island (UHI) is a key feature of urban climate. In order to compare the urban heat island phenomenon of Beijing city between summer and winter, Landsat 5 TM images acquired on August 31st 2001 and December 21st 2001 respectively were used to retrieve land surface temperature (LST) of Beijing city based on the generalized single channel algorithm which is a new algorithm applicable to retrieve land surface temperature from only one thermal channel remote sensing image. Then seasonal urban thermal environmental changes were analyzed. The result shows that urban heat island exists in both winter and summer and distribution maps of urban thermal environment are both ring-shaped, which is in accordance with the ring-road system of Beijing city. The result also indicates abnormity exists in the outskirts in winter and reasons for this phenomenon were found.