泛长三角地区城市的空间结构演变

Evolution of urban spatial structure in the Pan Yangtze River Delta

随着长江三角洲经济发展带来的环境和成本问题,长江三角洲泛化势在必然。研究泛长三角地区的空间结构演变有利于正确认识和把握其空间发展规律,从而为泛长三角地区的发展提供科学依据。基于扩散理论并结合现代GIS空间分析技术,构建场扩散模型,从城市场空间结构演化角度分析泛长三角地区核心—边缘结构的形成过程。研究发现:泛长三角地区经历了行政中心孕育、行政中心极化、点轴扩散、网络化过渡和复合式核心—边缘结构形成五个阶段。城市场主体区经历了"之"字型—"几"字型—"虾"型—"鳊鱼"型四种空间形态;场强极强区—场强较强区—场强一般区面积呈递增格局并且各自逐年递增;城市节点、扩散通道(线)、行政区面的扩散值大大增强,但中部区域普遍大于外缘地带。

With the rapid development of economy, there has emerged economic diffusion of the Yangtze River Delta. Research on the economic diffusion can help us have a better understanding of space evolution, forecast its future development trend and provide the basic data and scientific analysis for regional integration of the Pan Yangtze River Delta. Based on the diffusion theory, a diffusion effect model of field logarithmic（DEMFL） is constructed with the aid of the modern GIS spatial analysis technology. In addition, the formation process of a core-periphery structure in the Yangtse River Delta economy zone is analyzed according to the evolution of field spatial structure in cities.The research shows that the evolution of the economic spatial structure in the Pan Yangtze River Delta has gone through five phases： the inoculation of administrative center, the polarization of administrative center, the point-axis diffusion, the transition of network and the compound core-periphery structure. Obviously, the five phases are closely related to the social and economic development of the Pan Yangtze River Delta.The primary urban field regions are distributed along the Yangtze River and Hangzhou Bay. The urban district of field intensity has gone through four kinds of spatial forms： the Chinese character ＂之＂ – ＂几＂ – the aquatic animal ＂shrimp＂ – ＂parabramis pekinensis＂. It can be seen that the evolution of urban spatial morphology has gone through the evolutionary process from spot to line, and then from line to surface. The regions of field intensity in middle cities are much larger than those in outer regions, which apparently has a close relationship with the economic status and traffic convenience in these regions.The area displays an increasing trend ranging from the districts of extremely strong field intensity to the districts of strong field intensity, as well as the districts of ordinary field intensity. Furthermore, the three kinds of districts expand year by year respectively. However,the districts of weak field intensity and the districts of extremely weak field intensity are decreasing year by year. The diffusion value of city nodes, diffusion channels and administrative districts increase greatly, but this situation appears more commonly in middle regions than in outer regions. The spatial distribution of field intensity in city nodes and the whole diffusion area is uneven. Generally speaking, the urban field intensity in the Yangtze River Delta is stronger than that in outer regions. The increasing diffusion value of diffusion channels benefits from these newly built traffic lines as well as the improving grades of traffic lines.