Dynamic Change Analysis For Heat Island Effects Of Hefei Based On Remote Sensing Data And Landscape Ecology Theory

In recent years，in the context of rapid progress of urbanization，the urban heatenvironment was one of the main factors that dominate the urban environment. The urbanconstruction greatly changed the underlying surface thermodynamic properties，whichclosely linked with the formation of the heat island effect. Hefei，as the capital of AnhuiProvince，has undergone a rapidly economic development and fast acceleration ofurbanization in recent years. This resulted in changes of a lot of farmland and woodlandinto urban construction. Although known as the Garden City, Hefei can not be avoid theheat island effect. Therefore，it is necessary to study the characteristics of the spatialdistribution, evolution, causes and mitigation of the urban heat island effect in order toprovide a theoretical basis for making Hefei into a beautiful and comfortable modern city.Based on the basic principles of thermal infrared remote sensing and methods oflandscape ecology with the satellite remote sensing data, by using RS and GIS technology，the spatial distribution，the dynamic evolution of urban heat island，and the effects ofthermal landscape pattern，land use change were studied in Hefei. The relationship betweenvegetation parameters and urban heat island intensity was analyzed. The results are asfollows.The spatial distribution characteristic and the dynamic evolution of urban heat islandeffect in Hefei：There were significant heat island effect in2002,2006and2010in Hefei.The heat island occurred only in the urban center in2002. It was similar to2002in2006.In2010, however, the heat island area was fully expanded, with somewhat decrease inheat island intensity in some area. The heat island was significant only in the summer witha strong intensity while not very obvious in the other seasons.Analysis of dynamic changes in the pattern of thermal landscape: The thermallandscape pattern maps of Hefei were obtained by normalizing the surface temperaturedata. In2002, the plaque area ratio and largest patch index were larger in the lowtemperature region than in the other thermal landscape types, indicating that the lowtemperature region was the dominant plaque. The dominant plaque in2006was similar to2002. The patch area ratio and largest patch index of the middle temperature region werelargest in all thermal landscape types in2010，indicating that the middle temperatureregion was the dominant plaque. From2002to2010，the dominant plaque of the thermallandscape types was changed from low temperature region into the middle temperatureregion，and the middle temperature region was mainly distributed in the urban center. Therefore, the intensity of the urban heat island as a whole has been enhanced.Use visual interpretation to classification the land-use in Hefei，and analyze the impactof land use change on the urban heat island. From2002to2010，the urban land area hasbeen sharp rise，while the farmland area dropped sharply，and the reduce of farmlandmainly converted into urban land. In all land-use types，the average temperature of theurban land was highest，the average temperature lowest was water. The urban land toenhance the urban heat island intensity，while the waters to mitigate urban heat islandintensity of the best，followed by green land and farmland. The expansion of urban landarea resulted in the expansion of the urban heat island spatial distribution.Analysis of the relationship between NDVI，GVI，Pv with the surface temperature.There was a significant negative correlation between NDVI and surface temperature，the greater the NDVI the lower surface temperature，the linear regression equation wasy=303.31-10.23x（R~2=0.63）.There was a significant negative correlation between GVI andsurface temperature too，the linear regression equation was y=304.66-10x（R~2=0.62）.NDVI and GVI almost identical to the indicated effect of the spatial distribution of thesurface temperature and the Pv indicated effect was slightly worst.