A study on urban growth, vegetation space variation and thermal environmental changes of Beijing city based on TM imagery data

With the adoption of opening up and reform policy, growth of Beijing city has accelerated and exerted a dramatic influence on its thermal environment. Urban growth, vegetation space variation and their influence on the thermal environment of Beijing city were analyzed based on the 3 scenes of Landsat5 TM data acquired on September 26th 1987, August 28th 1994 and August 31st 2001 separately. Radiometric normalization between the three images from different dates was made firstly, followed by information extraction of urban growth and vegetation changes. The generalized single channel algorithm proposed by Jiménez-Muñoz J C, et al. in 2003 was applied to retrieve land surface temperature (LST) and thermal environmental changes were examined based on the normalized LST. The result shows urban growth area coincides with the thermal intensified area and a good similarity exists between vegetation increasing area and thermal relieved area or no change area. The characteristics of urban growth and thermal intensified area changes were similar, both spreading from the center of Beijing city to its outside in accordance with the ring road system.