Urban Expansion in Wuxi City and Heat Island Response by RS Analysis

Taking the Landsat TM / ETM + images of Wuxi City in 2001and 2008 as the data source,this paper uses the DBI-SAVI index to extract the information of town in Wuxi City,and achieves the urban expansion map of Wuxi City from 2001 to 2008.At the same time it uses thermal infrared band to invert the urban surface temperature,and respectively achieves the surface temperature map of Wuxi City in 2001 and 2008.At last,combining with urban thermal field variance index and the data of socio-economic and humanities,the relationship between urban expansion and heat island response is analyzed.The results show that urbanization of Wuxi City presents a growing trend from 2001 to 2008,with an uneven development of spatial expansion which mainly includes centralized development and ribbon-shaped development.The mostly direction is along the centerline of Changzhou-Wuxi-Suzhou Cities and encircles the Taihu Lake.The expansion speed in south-east is the fastest.In the process of urban expansion,surface temperature of Wuxi City has increased,area of urban heat island has been growing,and from ribbon-shaped to dumbbell-shaped distribution,urban expansion and heat island distribution have shown consistency in space,so urban heat island is a direct reflection of the urban expansion.