On The Urban Growth Of Jiangsu Province From 1985- 2014 Based On Impervious Surface Information From Remote Sensing Imagery

Impervious surface is an important indicator in the study of urban sprawl and regional environment using remote sensing data. Urban sprawl is an important measure to evaluate the level of urbanization, also an important area in the land use/cover change research. Jiangsu Province, as an important part of "Yangtze River Delta" metropolitan, has an important reference for regional development and national urbanization. Using multi-temporal images collected by different Landsat TM, ETM+and OLI sensors, the impervious surface areas of Jiangsu Province are extracted, and the rules and trends of spatio-temporal change are analyzed in detail. Furthermore, the corresponding characteristics and driving forces are also discussed.The main findings are as follows:(1) Biophysical Composition Index(BCI) has a good applicability in extracting impervious surface area from remote sensing images captured by different Landsat sensors, and shows better applicability and more accurate results in the big region. In order to avoid the fuzzy threshold of the experiment in a large area with many scenes of images, a histogram based threshold selection method was recommended. This method can greatly improve the efficiency with precise results.(2) According to the analysis of the province’s impervious surface in 1985,2000, 2014, the distribution of impervious surface mainly follow the pattern of main city, and extend through different ways with the small development outside the city.Through urban expansion index, the urban sprawl in Jiangsu province during 2000-2014 is larger than that during 1985-2000, and during 1985-2000, North Jiangsu has the fastest spread speed, while Middle Jiangsu shows the slowest speed; during 2000-2014, there is an opposite trend. South Jiangsu has a relatively stable expansion and a higher level expansion speed during the two period. Natural factors influence urban space layout, and the social and economic factors also bring strong power, while policy factors guide the urban spatial structure.(3) By choosing Nanjing, Nantong, Xuzhou as case study areas, the trends and characteristics of the surface characteristic parameters are explored. The results show that between 1985-2014 the impervious surface and built-up surface significantly increased, and vegetation coverage decreased, consequently the urban heat island effect is exacerbated which can match with the trend of urban sprawl pattern. Finally, all the results indicate that urban sprawl the urban heat island have a high correlation with BCI and NDBI, so BCI can be used in evaluating urban expansion.