改革开放以来,中国涌现出大规模的"乡—城"流动人口,深刻改变着中国的城市规模体系结构,不同规模城市间的人口集疏表现为显著的不均衡特征。根据1990年、2000年、2010年三期人口普查数据,构建中国城市人口及其流动人口的空间数据库。借鉴城市位序规模理论,提出城市流动人口服从类似规律的假设,探究城市流动人口位序规模分布服从的数学规律,进行斜率等关键参数的测算和无标度区的识别,并根据城市人口位序规模分布与城市流动人口位序规模分布耦合关系,将城市划分为吸纳流动人口绝对超前型、相对超前型、相对滞后型、绝对滞后型等4种类型。研究表明:1中国城市流动人口位序规模分布符合幂函数,且向高位序城市集聚的特征显著,集聚力量大于分散力量,这种极化特征不断提高。2中国大多数城市属于绝对滞后型,其流动人口规模仍未达到其理论值,具有较大的提升空间与潜力。3特大和大城市的流动人口位序规模大多超前,其流动人口集聚能力持续提升,目前大多已相对超载;而中小城市的位序规模大多滞后,其流动人口集聚能力一直较弱,目前大多相对规模不足,提升潜力与空间极大。4城市在经济水平、公共服务水平等引力上差异、流动人口自身的地域认识和定居意愿等均是影响中国城市流动人口位序规模分布的重要因素。
Since the reform and opening up, the migration of floating population from rural to urban area, which rebuilds China's urban size system, is being mirrored in China. And there was a large gap of floating population among cities of different sizes. According to census data in 1990, 2000 and 2010, this paper builds up the spatial database of urban floating population and total population. Referring to the theory and the parameters meaning of urban total population rank-size rule, this paper puts forward an assumption that it is similar to explore mathematic rule of urban floating population rank-size distribution by calculating the parameters and identifying the fractal scaling region. According the coupling relationship between rank-size distributions of urban floating population and total population, this paper divided cities into four coupling types in terms of absorbing floating population, which are absolutely advanced type, relatively advanced type, absolutely lagging type and relatively lagging type. Some interesting findings are listed as follows.(1) China's urban floating population rank-size distribution was also submitted to typical power function rule, with a highrank oriented aggregation feature. What's more, agglomeration power was stronger than dispersive power which improves the degree of aggregation.(2) Among the four types, the majority of cities have always been belonged to the absolutely lagging type, which means that the majority of Chinese cities still have rather large potential for absorbing more floating population.(3) The cities of different sizes located in southeastern coastal urban agglomeration and capital cities in central and western China were usually characterized as the absolutely advanced type or the relatively advanced type. These cities should focus on making floating population into local residents. While those cities with middle small sizes located in northern China's coastal areas, central China, western China and Northeast China were usually characterize