The Study On Urban Heat Island Effect In Chang-Zhu-Tan Urban Fringe

Urban Heat Island is defined as phenomenon of difference in temperature that urban temperature is higher than suburban temperature,highly influenced on environmental ecological system and activity of human being.In these years,Because of its macroscopic, multi-spectral and multi-temporal advantage,3S(RS,GIS,GPS) applied to urban thermal island research,which becomes a new hotspot of environmental science.On the basis of the research results at home and abroad,the data of remote sensing image of Chang-Zhu-Tan in 2001 and 2006,together with field survey,the UHI,the green space and the relationship between vegetation cover and UHI in Chang-Zhu-Tan were investigated using the technology of remote sensing and geography information system.Suggestions for mitigation of the UHI in Chang-Zhu-Tan were also proposed.The main results are as follows.1.Dynamic changes of urban heat island effect in Chang-Zhu-Tan.The distributions of brightness temperature(B.T.) were analyzed detailed by making use of the Landsat TM heat infrared bands in 2001 and 2006.Results showed that the areas of UHI significantly expanded with the development of Chang-Zhu-Tan city,and the UHI expanded along the roads in and out of the city or spread in the form of patches in newly development zones.These results indicated that urban expansion and industrial construction were the tow major driving forces of UHI.The property of underlying surface,artificial heat and emission gas all influenced the intensity of UHI.2.The distribution and change of green space.The normalized difference vegetation index(NDVI) map of 2001 and 2006 were produced with TM image data,and then the distributions of greens spaces in Chang-Zhu-Tan were analyzed.The change of green space information was obtained by composing of real color method.These results showed that the vegetation cover assumes the declining trend.The area of vegetation cover space decreased by 196.20 km~2 from 2001 to 2006,and the major part concentrates around the built-up district, which is the result of urban expansion,industrial development and the countryside residential area expands.The study on relation between vegetation cover and urban heat island discovered that vegetation cover changes and urban heat island changes coincided very well, and the green space could greatly mitigate the UHI.