论文标题
城市人口增长的空间结构
Spatial Structure of City Population Growth
论文作者
论文摘要
我们在这里表明，在县一级解决的人口增长在美国都会大都会统计区之间是在空间上异质的。我们对3,100多个美国县的数据分析表明，2015年至2019年期间国内移民导致的年度流量比自然人口增长大得多，并且主要负责这种异构增长。更准确地说，我们表明城市内流通常沿负人口密度梯度，而城市间流则集中在高密度的核心区域。城市内流是各向异性的，通常针对城市外部县，驱动不对称的城市蔓延。这种国内移民动态还负责通过重新分配给定城市的流入来缓解当地人口冲击。与在城市一级观察到的相比，这种“溢出”效应在县一级导致了县级的人口动态。了解国内移民流的空间结构是分析其驱动因素和后果的关键要素，从而代表了城市政策制定者和计划者的重要知识。
We show here that population growth, resolved at the county level, is spatially heterogeneous both among and within the U.S. metropolitan statistical areas. Our analysis of data for over 3,100 U.S. counties reveals that annual population flows, resulting from domestic migration during the 2015 - 2019 period, are much larger than natural demographic growth, and are primarily responsible for this heterogeneous growth. More precisely, we show that intra-city flows are generally along a negative population density gradient, while inter-city flows are concentrated in high-density core areas. Intra-city flows are anisotropic and generally directed towards external counties of cities, driving asymmetrical urban sprawl. Such domestic migration dynamics are also responsible for tempering local population shocks by redistributing inflows within a given city. This "spill-over" effect leads to a smoother population dynamics at the county level, in contrast to that observed at the city level. Understanding the spatial structure of domestic migration flows is a key ingredient for analyzing their drivers and consequences, thus representing a crucial knowledge for urban policy makers and planners.
