TEMPORAL-SPATIAL CHARACTERISTICS OF EVOLUTION OF THE URBAN SYSTEM IN THE YANGTZE RIVER DELTA

Based on non-agricultural population data from 1986 to 2007,by using qualitative analysis and various quantitative methods such as scale-rank law,ROXY law and so on,this paper systematically analyzed temporal-spatial characteristics of the evolution of system in the Yangtze River Delta,in view of two issues in development of system:grade scale structure,spatial structure.The results showed that:urban agglomeration was in the trend of decentralization,the number of medium-sized cities increased significantly,and the non-agricultural population concentration of gravity gradually transferred from the traditional big cities to the small and medium-sized cities.Shanghai was the key city in the region.It played a leading role in the regional development,and influenced far beyond the scope of the region.Took Shanghai as the center,Nanjing,Shanghai-Hangzhou,the Yangtze River as the axis to form the remarkable significant layer structure,Xinghua,Gaoyou,western region of Hangzhou,Taizhou were less affected by big cities.Shanghai-Suzhou-Wuxi formed the urban of close internal linkages and fuzzy hierarchy,which was core of the Yangtze River Delta and advanced form of continuous development of urban.Despite the lack of scale advantages in the second-tier cities,Nanjing and Hangzhou played a prominent role in the region due to their location,that is,actually take the role of the regional sub-center.Around the area and two vice center,the Yangtze River Delta built a type of development spindle.