长三角地区人口城镇化的空间极化过程及其演变格局研究

在中国人口城镇化的快速推进下，人口非对称流动引致的城市间集聚差异不断循环累积而产生空间极化现象，研究极化形成的格局及其空间效应对区域协调发展具有重要现实意义。论文以长三角地区的41个城市为研究案例，构建人口城镇化水平综合评价指标体系，在测度2000—2019年人口集聚指数的基础上，运用极化指数和变异系数等，探究长三角人口城镇化空间极化的演变过程、空间特征及其正负效应。研究发现：① 2000年以来长三角地区人口城镇化的时空分异逐年上升，空间极化度提高近40%，城市发展的非均衡性不断增强；空间极化表现出随尺度放大而递增的趋势，呈现出长三角地区整体大于长三角城市群的极化特征，形成“上海—南京—杭州—合肥”的“多中心”空间极化格局，核心区已演变为空间正极化区域。② 随着人口集聚程度的变化，不同维度的空间极化时空分异不断扩大，高值区主要集中在以上海—南京为中心的长三角沿江轴线上，由此向安徽、江苏北部、浙江南部等区域递减，呈现明显的“核心—边缘”结构，形成人口素质>人口结构>人口潜力的空间极化态势。③ 研究期内绝大多数城市的极化水平发生了的跃迁，正—正型和负—负型城市的增多加剧了区域的空间极化效应，呈现出“哑铃型”分布特征。④ 在人口城镇化中，人口结构是长三角地区空间极化的主要驱动力，未来不断提升人口素质，并调控正—正型和负—负型城市分别向正—负型和负—正型城市转型将有助于推动长三角地区人口城镇化高质量协调发展。

Process of change of the spatial polarization of population urbanization in the Yangtze River Delta region

With the rapid advancement of population urbanization in China, the agglomeration differences between cities caused by asymmetric population flow continue to accumulate and generate spatial polarization. The study of the pattern of polarization formation and its spatial effects is of great practical significance for coordinated regional development. Taking 41 cities in the Yangtze River Delta region as research cases, this study built a comprehensive evaluation indicator system for the level of population urbanization. On the basis of measuring the population agglomeration index from 2000 to 2019, this study used polarization index and coefficient of variation to explore the evolution process, spatial characteristics, and positive- negative effects of the spatial polarization of population urbanization. The research found that: 1) Since 2000, the spatial and temporal differentiation of population urbanization in the Yangtze River Delta region has been increasing year by year, the spatial polarization has increased by nearly 40%, and the unevenness of urban development has continued to increase; The overall polarization of the Yangtze River Delta region is larger than that of the Yangtze River Delta urban agglomeration, forming a multi-center spatial polarization pattern with Shanghai-Nanjing-Hangzhou-Hefei as centers, and the core area has evolved into a spatially positive area. 2) With the change in the degree of agglomeration, the spatial and temporal differentiation of spatial polarization in different dimensions continues to expand. The high-value areas are mainly concentrated along the Yangtze River Delta axis with Shanghai-Nanjing as the center, and then decrease to Anhui, northern Jiangsu, and southern Zhejiang. It presents an obvious core-periphery structure, forming a spatial polarization trend of population quality > population structure > population potential. 3) During the study period, the polarization level of most cities has changed. The increase of positive-positive and negative-negative cities has intensified the spatial polarization effect of the region, showing a dumbbell-shaped distribution characteristic. 4) In the process of population urbanization, population structure is the main driving force of spatial polarization in the region. In the future, continuously improving the population quality and regulating the transformation of positive-positive and negative-negative cities into positive-negative and negative-positive cities will help promote the high-quality and coordinated development of population urbanization in the Yangtze River Delta.