基于城市流空间的城市群变形结构识别——以长江三角洲城市群为例

全球化、信息化时代,城市群空间结构在城市流的作用下发生剧烈的变形。基于长三角城市流的测度和关系矩阵构建,通过流要素分析、多维尺度分析,从“节点-联系-格局”3个方面识别流空间下城市群变形结构。研究表明：流空间下城市中心性层级特征变化明显,中间层级的城市数量大幅增加;局域范围内城市流网络仍受地理空间距离的制约,但高等级城市流具有跨地理空间流动特征;中心城市和边缘城市呈“异化”发展趋势,表现为中心城市的集聚组团以及边缘城市的分散偏离。

Identification of Urban Agglomerations Deformation Structure Based on Urban-flow Space: A Case Study of the Yangtze River Delta Urban Agglomeration

The expansion of informatization, networking and globalization makes internal communication of urban agglomeration increased sharply. Due to the powerful shaping strength of urban flows, spatial structure of urban agglomeration has suffered dramatic structure deformation. It is meaningful to identify and optimize the structure of urban agglomeration from the prospect of the urban flow. Based on economic-social data and road traffic data of the Yangtze River Delta in 2014, this article carries on a comprehensive measurement of urban flow in the Yangtze River Delta. From the prospects of “Node-contact-pattern”, we try to identify the deformation structure of the Yangtze River Delta urban agglomeration with Multidimensional Scaling Analysis. The results indicate that: 1) At the node level, there is a significant hierarchy change of urban centricity in flow space. 67 cities are divided into four levels, the number of middle level city (including level I and level II) in flow space increased dramatically in contrast to traditional rank-size distribution. 2) The connections between nodes in local districtsare restricted to the law of geographic space distance, but high level flows exist between Nanjing, Shanghai, Hangzhou and some other cities, which characterized by the trans-regional intercourse feature and “7” glyph structure in space. 3) In terms of node spatial pattern identification, Multi-dimensional Scaling Analysis can make multidimensional connection matrixreduce to two-dimensional space matrix, the result is more objective and intuitive. Flow space structure pattern shows a dramatic deformation due to the core node “concentration” and the edgenode “discrete”. On one hand, cities such as Shanghai, Hangzhou, Nanjing, and Suzhou present a group concentration, which formed a “core area” characterized by large-scale, continuous urban space, and closely connection; On the other hand, cities in the north of the Yangtze River and south of Hangzhou bay show a scattered deviating trend from the “core area”. In order to improve the efficiency and integration level of the Yangtze River Delta, urban agglomeration, economic development and transport network construction of those structural deviation cities should be noticed by both state and local governments.