AN ANALYSIS ON THE COUPLING RELATIONSHIP BETWEEN URBAN VEGETATION AND LAND SURFACE TEMPERATURE IN HANGZHOU BASED ON ASTER IMAGERY

Both urban vegetation and urban land surface thermal environment (ULSTE) are vital factors to the health of citizens, city image and the further development. Urban vegetation is greatly influenced as the development of social economy and the urban expansion, and the ULSTE is significantly changed as well. Therefore, they have both been the most important components in urban ecological environment research. On the other hand, land surface temperature (LST) is the main factor of ULSTE. The coupling relationship between urban vegetation and LST is therefore of great interest to a variety of environmental studies Hangzhou, the provincial capital of Zhejiang Province in China, is also well known as the tourism city in and out of China. The ecological environment plays an important role in the influence of city image and further development. This paper chooses Hangzhou as the study area, and the urban vegetation and LST is monitored and analyzed utilizing Terra ASTER imagery in the year 2007. The coupling relationship is studied accordingly, so as to provide the basis for decision making of ecological planning and environment protection. The research consists of 3 steps: 1) Retrieval of urban vegetation and urban forest from ASTER image. Urban forest plays a much more important role in most of the ecosystem subjects, so it is chosen as a special part of urban vegetation for the analysis; and both urban vegetation abundance (UVA) and urban forest abundance (UFA) are estimated in each pixel of ASTER image. UVA is calculated utilizing the dimidiate pixel model, while the LST is calculated using a classification and regression tree algorithm. 2) Retrieval and analysis of LST in the urban area of Hangzhou. LST is calculated introducing a split-window algorithm 3) Coupling relationship research between urban vegetation and LST. This is the main part of this paper. Firstly, the relationships between NDVI and LST are studied in the following 3 parts: 1, th