基于南京市第五次和第六次人口普查分乡镇、街道数据,通过街道和圈层双尺度分析了人口老龄化的程度差异、空间差异以及空间相关性,探讨南京市街道老年人口的空间分布格局,采用热点区演化分析了街道老年人口的时空演变特征。结果显示:①近10年南京市街道老龄化系数总体上呈现"跨越式"圈层蔓延扩散的空间分布特征,处于老年人口成长阶段的街道由分布在中心城区和主城区的交界地带转变为向主城区蔓延的趋势,轻度老龄化的街道分布在中心城区,中度老龄化阶段的街道集中分布在主城区和郊区,重度老龄化阶段的街道以郊区为主。②街道老年人口密度类型为密集区,密度最高的区域位于中心城区,郊区次之,主城区内密度最低。③南京市街道人口老龄化率呈现显著的空间正相关,随着时间的推移,街道人口老龄化在空间上的差异增大,集聚效应减弱,空间上的发展渐趋不均衡。热点区分布呈现"冷-次冷-次热-热"的圈层式空间分布格局。④从历史因素、人口生命周期、城市变迁三个角度分析了影响南京市老年人口分布和演变的主要因素。

Based on the fifth and sixth population census data at township and street level, we analyzed the degree difference, spatial difference and spatial correlation of population aging in Nanjing at the street and circle levels, and discuss the spatial distribution pattern of elderly population. With the help of method of the evolution of hot spots, we also explore the spatial and temporal evolution characteristics of elderly population. Results suggest that:1)Nearly 10 years, the aging coefficient shows a "span type" circle spread distribution. 2)The density type of elderly population is compact district. The highest density areas are distributed in central urban areas, and the suburbs are the lower density areas, the main city areas tend to have the lowest density. 3)The population aging at street level in Nanjing presents a significant positive autocorrelation. Space difference becomes larger, agglomeration effect becomes weaker and spatial development is unbalanced over time. The distribution of hot spots shows a "coldest-colder-hotter-hottest" spatial distribution pattern. 4)The main factors that affect the distribution and evolution of the aged population in Nanjing are analyzed from three aspects, the historical factor, the life cycle and the change of the city.