Study On The Land Use Change And Information Extraction Of Urban Heat Island And Evaporation/Transpiration In Fuzhou City With Its Surrounding Areas Of SE China

Remote sensing technology has been used in this thesis to study the land use changes and urban expansion of the Fuzhou area in SE China in the years from 1996 to 2003. The urban heat island and evaporation/transpiration information of the area were also extracted and related to the land use change and urban expansion to see their interaction for the urban heat environmental changes during this period. The study was based on two Landsat TM/ETM+ images acquired on September 6, 1996 and May 29, 2003 respectively and a SPOT 5 multispectral image dated on December 14, 2003. To reveal urban expansion areas, the original 7-band TM/ETM+ image was compressed into a 3-band image using the band-dimension compression technique. The 3 new bands were derived from three thematic indices, which are Soil Adjusted Vegetation Index (SAVI), Modified Normalized Differences Water Index (MNDWI), and Normalized Differences Built-up Index (NDBI). A supervised classification was carried out on this new 3-band image and the urban built-up lands were extracted from the classified maps. The results show that the urban area of Fuzhou City has increased by 86.9 km~2 during the seven-year study duration. The expanded areas are generally coordinated with the City's Planning. The at-satellite temperatures of the study years were derived from the thermal infrared bands of the two Landsat images. The Urban-heat-island Ratio Indexes of two study years (URI) were further computed for the city. The results reveal that the URI has increased from 0.44 to 0.48, indicating an increase in urban heat island distribution area from 1996 to 2003. The regional evaporation/transpiration was also computed using the Surface Energy Balance Algorithm for Land (SEBAL). This indicates a great decrease in evaporation/transpiration in the expanded urban areas. The correlation analysis among evaporation/transpiration, urban heat island and vegetation changes within the expanded urban areas shows that both evaporation/transpiration and vegetation are negatively correlated with the urban heat island.