基于夜光遥感影像的粤港澳地区城市发展时空格局演变

将VIIRS时间序列夜光遥感影像首次应用于粤港澳地区,结合LandScan ^TM人口分布图等辅助数据,采用夜间灯光统计、位序-规模法则以及由基尼系数构建的夜光发展指数等方法,在地市级、区县级2种尺度上对其城市发展空间格局进行分析,探究其城市规模的时空演变情况。结果发现,2012—2018年粤港澳地区所有城市的夜光总量均呈现出增长的态势,但中小城市的增速明显高于大城市,汕尾市的夜光增长率高达310.35%。在位序-规模分析中,地市级与区县级的q值在2012—2018年分别下降了16.86%和13.52%,城市规模分布趋于分散的力量大于趋于集中的力量,城市间规模发展日趋平衡。夜光发展指数同样随时间的变化逐渐降低,城市内部夜光与人口之间的分配水平差距正逐渐弥合,中小城市的发展相对更快。同时,夜光发展指数下降最为显著的几个地级市均位于粤东地区,说明粤东地区近年来正展现出强劲的发展态势。

A Spatial-Temporal Pattern Evolution Analysis of Urban Scale Development in the Guangdong-Hongkong-Macao Region Based on Nighttime Light Imagery

Taking the Guangdong-Hongkong-Macao region as our study area,we first used the time series data fitting method in TIMESAT to improve the quality of VIIRS nighttime light remote sensing images.We then generated annually averaged nighttime light images from the repaired VIIRS monthly composite data from June 2012 to May 2019.These,combined with the LandScan^TM population distribution map and administrative division data,were used to analyze the spatial and temporal patterns of urban development in the Guangdong-Hongkong-Macao region for the first time,using a spatial statistics method,rank-size distribution method,and the Nighttime Light Development Index(NLDI)constructed using the Gini coefficient.The experiment was performed at both prefecture and county levels.The following conclusions can be drawn from this study.1)From 2012 to 2018,the total amount of nighttime light in all prefecture-level cities in the Guangdong-Hongkong-Macao region showed an increasing trend.The total amount of night light in Guangzhou has always been highest,with Shenzhen,Dongguan,Foshan and other economically developed cities maintaining steady increases.The growth rate of nighttime light in small and medium-sized cities was significantly higher than in large cities,and was as high as 310.35%in Shanwei City.Small and medium-sized cities located in the surrounding areas show great development potential.2)In the rank-size distribution analysis,from 2012 to 2018,the q value at prefecture level and county level decreased by 16.86%and 13.52%respectively.At the prefecture and city level,the distribution of urban scale has gradually changed from a first-place distribution to a rank-size distribution.At the district and county level,it has remained a first-place distribution,but the tendency to disperse has been greater than the tendency to concentrate.The"Core-Edge"urban network structure that had prevailed in the Guangdong-Hongkong-Macao region for a long time has gradually been broken.The gaps between urban structure levels are gradually narrowing,and the scale development is gradually becoming more balanced across the whole region.3)It can be seen from the analysis of the Nighttime Light Development Index that the differences in nighttime light levels and population distribution levels in the Guangdong-Hongkong-Macao region are gradually decreasing,with the imbalance between cities showing a decreasing trend year by year.The rate of decrease of NLDI in small and medium-sized cities is faster than in large cities,which indicates that the development of small and mediumsized cities is faster.The NLDI values of Jieyang City,Shanwei City and Shantou City,which are all in the east of the Guangdong-Hongkong-Macao region,decreased most significantly,indicating that the east of the region has shown a strong development trend in recent years.This paper presents an analysis the evolution of urban scale distribution in the Guangdong-Hongkong-Macao region from the perspective of spatial statistics,and its dynamic urban development in recent years is discussed herein.These findings have both theoretical and practical significance for optimizing development as well as for scientifically informed distribution of resources in the region.