中国中部地区城镇体系规模结构演变

Evolution of Urban System Structure Scale in Central China

基于城区常住人口指标,运用城镇体系规模分析的多种方法,分析1995—2017年我国中部地区多尺度的规模结构演变特征。结果表明:(1)地级市数目与人口金字塔均由较规则塔形结构演化成"纺锤型";建制市数目金字塔趋于完善,人口金字塔演化成"纺锤型";城镇数目金字塔变化不明显,人口金字塔演化为不规则形。(2)城市首位度指数呈现波动性下降趋势且逐渐偏离理想值,以武汉、郑州为首的高位序城市的辐射带动作用不理想。(3)整体城市规模体系符合分形规律但体系分布日益分散,拟合线不断向外偏离。地级市视角下拟合线斜率波动变化,建制市及城镇视角下斜率逐渐减小。(4)城镇密集区范围均不断扩大,且在同时间段内集聚程度由强至弱、集聚范围由大到小依次为县城、建制市、地级市。地级市和建制市的核心集聚区最终演变为以合肥为顶端,以郑州、太原为"撇",以武汉、长沙为"捺"的"人字型"结构;城镇密集区由以武汉、郑州为核心的"双星"格局演变成以武汉、郑州、合肥、长沙为增长极的"四核T字型"分布格局。

Based on the index of urban resident population, using multiple methods of urban system scale, the rank-size structure evolution of three scales in Central China from 1995 to 2017 was researched. The results were shown as follows. Firstly, the urban system pyramid structure by the index of number and population changed from relatively regular pyramid to “Spindle shape” at prefecture-level city. The number pyramid was gradually improved and the population pyramid was evolved to “Spindle shape” at common country. However, the number pyramid didn’t change obviously and the population pyramid was evolved to irregular structure at country town. Secondly, from the point of law of primate city, the structure showed a declining trend which was gradually away from the ideal value, and the radiating action in high-order cities headed by Wuhan and Zhengzhou hasn’t achieved an ideal result. Thirdly, from the point of rank-size rule, the overall urban system structure fitted the fractal pattern which scattered increasingly. In detail, the slope of the regression equation fluctuated at prefecture-level city, but it was showed a declining trend from the perspective of common city and country town. Fourthly, from the point of city-and-town concentrated area, it was enlarged day by day. However, the degree and range of agglomeration of city-and-town concentrated area was different in three scales, which ranked as country town, common city and prefecture-level city in descending order. Specifically, from the spatial distribution pattern, it gradually formed the “double star” pattern with Wuhan and Zhengzhou, and eventually evolved to “four cores with T-shaped” pattern with Wuhan, Zhengzhou, Hefei and Changsha as the growth poles.