Urban population during the daytime and at night and their spatial distribution are important bases for planning urban infrastructure, public services and disaster relief. As current population statistics cannot disti...Urban population during the daytime and at night and their spatial distribution are important bases for planning urban infrastructure, public services and disaster relief. As current population statistics cannot distinguish urban population during the daytime from that at night, existed research in this field are quite limited. This paper tries to advance studies at this aspect by establishing a relationship model for the three components of ＇population, land use and time （daytime or night）＇ to explore the temporal and spatial characteristics of different types of population, which is aimed to estimate urban population during the daytime and at night and to analyze their spatial characteristics at grid scale. Furthermore, an empirical case study has been carried out at the Haidian District in Beijing, China to test the model. The results are as follows： （1） The spatial structure of urban population during the daytime is significantly different from that at night. The spatial distribution of urban population during the daytime is more extensive and more agglomerated that that at night. （2） Several types of spatial coupling relationship between population during the daytime and that at night have been identified, such as sandwich mode, symmetry mode, convergence mode and single mode, etc. （3） The spatial distribution of daytime and nighttime population also reflects certain factors during the development of China, such as the distribution of old residential areas, the construction of new industrial districts, and the differences between urban and rural areas, which can provide reference points for studies in this field and other regional research.展开更多
This study examines the impact of spatial landscape configuration(e.g.,clustered,dispersed)on land-surface temperatures(LST)over Phoenix,Arizona,and Las Vegas,Nevada,USA.We classified detailed land-cover types via obj...This study examines the impact of spatial landscape configuration(e.g.,clustered,dispersed)on land-surface temperatures(LST)over Phoenix,Arizona,and Las Vegas,Nevada,USA.We classified detailed land-cover types via object-based image analysis(OBIA)using Geoeye-1 at 3-m resolution(Las Vegas)and QuickBird at 2.4-m resolution(Phoenix).Spatial autocorrelation(local Moran’s I)was then used to test for spatial dependence and to determine how clustered or dispersed points were arranged.Next,we used Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)data acquired over Phoenix(daytime on 10 June and nighttime on 17 October 2011)and Las Vegas(daytime on 6 July and nighttime on 27 August 2005)to examine day-and nighttime LST with regard to the spatial arrangement of anthropogenic and vegetation features.Local Moran’s I values of each land-cover type were spatially correlated to surface temperature.The spatial configuration of grass and trees shows strong negative correlations with LST,implying that clustered vegetation lowers surface temperatures more effectively.In contrast,clustered spatial arrangements of anthropogenic land-cover types,especially impervious surfaces and open soil,elevate LST.These findings suggest that city planners and managers should,where possible,incorporate clustered grass and trees to disperse unmanaged soil and paved surfaces,and fill open unmanaged soil with vegetation.Our findings are in line with national efforts to augment and strengthen green infrastructure,complete streets,parking management,and transit-oriented development practices,and reduce sprawling,unwalkable housing development.展开更多
城市昼夜人口数据是了解城市活力和城市综合治理的重要依据。本文以郑州市主城区为研究区,结合无线网络数据和兴趣点(Point of Interest,POI)数据构建人口吸引力指标,采用城乡分区策略和随机森林模型开展人口空间化实验,生成100 m格网...城市昼夜人口数据是了解城市活力和城市综合治理的重要依据。本文以郑州市主城区为研究区,结合无线网络数据和兴趣点(Point of Interest,POI)数据构建人口吸引力指标,采用城乡分区策略和随机森林模型开展人口空间化实验,生成100 m格网尺度的城市昼夜人口分布图;之后将结果与公开格网人口数据进行精度对比,并分析研究区昼夜人口分布格局。结果表明:1)融合无线网络数据和POI数据可以提高格网人口精度,能够有效反映城市昼夜人口分布差异;2)研究区人口分布呈现显著的“中心—边郊—乡村”的衰减模式,中心城区白天人口聚集效应高于夜晚,昼夜人口流动方式主要为内部流动;3)本文估算结果的各类误差均小于公开数据集,与真实人口信息更加符合。展开更多
基金National Natural Science Foundation of China, No.41271174 National Science and Technology Support Program, No.2012BAI32B07
文摘Urban population during the daytime and at night and their spatial distribution are important bases for planning urban infrastructure, public services and disaster relief. As current population statistics cannot distinguish urban population during the daytime from that at night, existed research in this field are quite limited. This paper tries to advance studies at this aspect by establishing a relationship model for the three components of ＇population, land use and time （daytime or night）＇ to explore the temporal and spatial characteristics of different types of population, which is aimed to estimate urban population during the daytime and at night and to analyze their spatial characteristics at grid scale. Furthermore, an empirical case study has been carried out at the Haidian District in Beijing, China to test the model. The results are as follows： （1） The spatial structure of urban population during the daytime is significantly different from that at night. The spatial distribution of urban population during the daytime is more extensive and more agglomerated that that at night. （2） Several types of spatial coupling relationship between population during the daytime and that at night have been identified, such as sandwich mode, symmetry mode, convergence mode and single mode, etc. （3） The spatial distribution of daytime and nighttime population also reflects certain factors during the development of China, such as the distribution of old residential areas, the construction of new industrial districts, and the differences between urban and rural areas, which can provide reference points for studies in this field and other regional research.
基金This research study is supported by a NASA-funded project(NASA award number NNX12AM88G)titled"Understanding Impacts of Desert Urbanization on Climate and Surrounding Environments to Foster Sustainable Cities Using Remote Sensing and Numerical Modeling."This material is also based upon work supported by the National Science Foundation under grant number BCS-1026865,Central Arizona-Phoenix Long-Term Ecological Research(CAP LTER),and under NSF award number SES-0951366 and SES-0345945,Decision Center for a Desert City(DCDC).
文摘This study examines the impact of spatial landscape configuration(e.g.,clustered,dispersed)on land-surface temperatures(LST)over Phoenix,Arizona,and Las Vegas,Nevada,USA.We classified detailed land-cover types via object-based image analysis(OBIA)using Geoeye-1 at 3-m resolution(Las Vegas)and QuickBird at 2.4-m resolution(Phoenix).Spatial autocorrelation(local Moran’s I)was then used to test for spatial dependence and to determine how clustered or dispersed points were arranged.Next,we used Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)data acquired over Phoenix(daytime on 10 June and nighttime on 17 October 2011)and Las Vegas(daytime on 6 July and nighttime on 27 August 2005)to examine day-and nighttime LST with regard to the spatial arrangement of anthropogenic and vegetation features.Local Moran’s I values of each land-cover type were spatially correlated to surface temperature.The spatial configuration of grass and trees shows strong negative correlations with LST,implying that clustered vegetation lowers surface temperatures more effectively.In contrast,clustered spatial arrangements of anthropogenic land-cover types,especially impervious surfaces and open soil,elevate LST.These findings suggest that city planners and managers should,where possible,incorporate clustered grass and trees to disperse unmanaged soil and paved surfaces,and fill open unmanaged soil with vegetation.Our findings are in line with national efforts to augment and strengthen green infrastructure,complete streets,parking management,and transit-oriented development practices,and reduce sprawling,unwalkable housing development.
文摘城市昼夜人口数据是了解城市活力和城市综合治理的重要依据。本文以郑州市主城区为研究区,结合无线网络数据和兴趣点(Point of Interest,POI)数据构建人口吸引力指标,采用城乡分区策略和随机森林模型开展人口空间化实验,生成100 m格网尺度的城市昼夜人口分布图;之后将结果与公开格网人口数据进行精度对比,并分析研究区昼夜人口分布格局。结果表明:1)融合无线网络数据和POI数据可以提高格网人口精度,能够有效反映城市昼夜人口分布差异;2)研究区人口分布呈现显著的“中心—边郊—乡村”的衰减模式,中心城区白天人口聚集效应高于夜晚,昼夜人口流动方式主要为内部流动;3)本文估算结果的各类误差均小于公开数据集,与真实人口信息更加符合。
