基于等级钟理论的中国城市规模等级体系演化特征

The Time-Scale Effects of the City-Size Hierarchy in China Based on Rank-Clock Methodology

首次引入国际著名城市地理学家M.Batty提出的"城市规模等级钟"、"等级距离钟"和"半生命周期"理论;利用地级以上城市的人口—等级数据,测算了表征中国城市规模等级演化特点的"等级钟"、"等级距离钟"和"半生命周期",探讨了演化过程与机制;利用历史人口数据,研究了若干历史城市近2000年间的"等级钟"演化特征。等级钟研究表明,中国特大城市的规模等级钟变化较小,城市位序稳定;在区域空间差异上,东部沿海城市等级钟变化明显,位序上升迅速;东北地区城市等级钟呈现较大变化,但演化方向与东部沿海城市相反,城市位序逐渐下降;西部和内陆城市等级钟变化缓慢,位序难以进入顶级序列之中。等级距离钟表明,中国高位序城市等级距离变化较小,低位序和新设立城市的等级距离变化明显,整个城市系统的变化较为平缓,仅在1980-1985年间和2000-2005年间出现较大变化,体现了中国在改革开放初期与21世纪开始的二次较为迅速的城市化发展历程。半生命周期研究表明,中国城市体系在生命周期现象不明显的总体背景下,以20世纪80年代为时间界标,百位城市的前、后半生命周期仍然显现有较为明显的时间尺度差异,自该时间界标以后,新兴城市替代传统城市的速度开始加快。中国历史城市"等级钟"表明,城市位序等级的变化是多种动因的叠加,以政治职能为主的城市位序与其政治地位密切相关;沿海、沿江城市的位序则更多地与地理区位条件和经济政策相关联。

The theories of ＂Rank-Clock＂, ＂Rank-Distance Clock＂, and ＂Half-Life of City＂ suggested by Prof. M Batty, a famous urban geographer in the world, has been introduced in this paper. Using data of population and cities＇ rank at and above prefecture for more than 50 years since the founding of the People＇s Republic of China in 1949, the ＂Rank-Clock＂, ＂Rank-Distance Clock＂ and ＂Half-Life of City＂ depicting the evolving characteristics of cities＇ hierarchy in China have been researched and drawn up. As well, using some historical population data, the ＂Rank-Clock＂ characteristics of a few historical cities in China for the last 2000 years have been researched and discussed briefly. The outcomes of the ＂Rank-Clock＂ study indicate that variations of the ＂Rank-Clock＂ of metropolises in China appear more slowly and the cities＇ rank order is stable. As for the regional spatial differences, variations of the ＂Rank-Clock＂ of cities located in eastern China are more evident, and their rank order advances more quickly. Correspondingly, although variations of the ＂Rank-Clock＂ of cities located in northeastern China are also greater, the direction of variations is opposite compared with that of eastern cities and their rank order drops markedly. Furthermore, variations of the ＂Rank-Clock＂ of a few cities located in western and inland China are relatively small, and their rank order is kept beyond the top 100 cities for the study periods. The outcomes of the ＂Rank-Distance Clock＂ study show that changes of ＂Rank-Distance＂ in some cities with higher rank order are relatively small, and changes of cities with lower rank order and/or newly established cities increase more quickly. As to the whole urban system of China, the Rank-Distance changes placidly, only in the periods of 1980-1985 and 2000-2005, the significant changes of the Rank-Distance took place, representing two rapid urbanization processes occurred in the early days of ＂reform and opening up＂ and the beginning of the 21st century. The results of the ＂Half-Life of City＂ study display that as a whole city system of China, because of the shorter temporal span of the system, the ＂Half-Life of City＂ is not evident. Even if that is how things stand, taking the 1980s as a demarcation line of time, there is a clear duration difference between the forwards and backwards half-life of the top 100 cities. Just starting from the demarcation line, the speed of replacing old cities by new developing ones is quickening. The outcomes of the ＂Rank-Clock＂ study for some historical cities show that rank changes of the cities with political functions are closely related to their political status as old administrative capitals. And rank changes of the cities located in eastern and coastal areas of China are closely related to their geographical conditions and economic policy.