基于辐射扩散测度的中国城市群发育格局识别

Identification of Urban Agglomeration in China Based on Radiation Diffusion Measurement

基于空间相互作用理论,采用合适的场强模型对中心城市辐射作用强度的高值区域识别,是界定城市群空间范围和全国城市群发育格局的重要方法。首先,以区县单元2010年的GDP和人口的几何平均值作为核心城市的结节性指数,采用辐射场能模型计算657个中心城市的辐射场强,得到全国公里栅格单元的辐射场强累加值;然后,用剖面曲率公式计算地理表面场强曲率,识别曲率高值区域即是辐射场强变化的"拐点"区域,研究确定识别城市群的空间曲率的两个关键阈值分别为60和80;最后将这些"拐点"区域所围成的场强高值区域提取出来即是城市群的空间范围。最终识别出:全国2010年共发育有18个城市群,其中都市连绵区、准都市连绵区和联合都市区的个数分别是3个、6个和9个。

Using the appropriate field model to identify the high value area of the radiation intensity of center city on the basis of the theory of spatial interaction is the important method to define the spatial scope and the growth pattern of urban agglomeration in the country. First, this paper calculates the geometric average of GDP and population in 2010 as the nodular index, uses the model of radiation field to calculate the radiation field strength of 657 center cities, and gets the accumulated value of radiation field strength of km grid units throughout the country. Second, the curvature of field strength of geographical surface is calculated by using the formula of section curvature. The high value areas of the curvature are the ＂inflection points＂ region of the radiation field intensity, and the two key thresholds to determine the spatial curvature of urban agglomeration are 60 and 80. Finally the extracted high field strength value areas surrounded by the ＂inflection points＂ are the scope of urban agglomeration. Eventually there are 18 urban agglomerations identified in 2010, including 3 metropolitan interlocking regions, 6 quasi metropolitan interlocking regions and 9 joint metropolitan regions.