中国地级以上城市建成区2006—2016年 人口密度变化的时空格局及驱动因素

土地扩张速度快于人口增长速度导致城市建成区总体人口密度下降，研究建成区人口密度的变化规律，对于城市健康发展决策具有重要意义。基于中国285个地级以上城市2006—2016年人口和建成区面积数据，分析中国城市建成区人口密度的变化趋势和空间分布差异，并探讨人口密度变化的驱动因素。结果表明：1）中国城市建成区平均人口密度由2006年的10 845人/km2降低至2016年的8 279人/km2，平均每年降低2.66%。2）超过5/6的研究城市的人口密度降低，但不同城市人口密度变化率存在显著差异。人口密度快速降低、中速降低、缓慢降低和密度增加的地级以上城市分别占比为13.3%、30.5%、41.1%和15.1%。3）人口密度快速降低城市主要分布在东部地区，人口密度中速降低和缓慢降低城市主要位于中部地区，人口密度增加城市呈现两极分化，主要包括北上深等人口快速流入城市和经济发展缓慢的小城市。4）经济发展水平、城市规模、区位因素、城市发展政策是影响人口密度变化的主要驱动因素。

Spatio-temporal Patterns and Driving Factors of Urban Population Density Change of Prefecture-level Cities in China during 2006-2016

When the rate of land expansion was faster than that of population growth, the overall population density would decrease in urban built-up areas. Studying the law of urban population density change in built-up areas is of great significance for the decision-making of national land safety and urbanization health development. Based on the data of the urban resident population and built-up areas in 285 cities in China during 2006-2016, this paper analyzes the temporal trends and spatial distribution of urban population density in Chinese cities, and explains the drivers of urban population density changes. The results show that: 1) The average population density within the built-up area in China decreased from 10 845 person/km2 in 2006 to 8 279 person/km2 in 2016, with an average annual decreasing rate of 2.66%. 2) The urban population density decreased in more than 5/6 cities, while there was a significant difference of the changing rate of population density among cities. Cities with rapidly decreased, moderately decreased, slowly decreased, and increased population density accounted for 13.3%, 30.5%, 41.1% and 15.1%, respectively. 3) Cities, experiencing rapidly decreased population density were mainly distributed in Eastern China. Cities with moderately decreased and slowly decreased population density were mainly distributed in the Central China. Cities with fast inflow of population experienced an increase of urban population density, such as Beijing, Shanghai, and Shenzhen. We also found that urban population density increased in some small cities with slow development of economy. 4) Economic development level, city scale, location factor and urban development policy are the main driving factors of population density change.