基于多源灯光数据的中原城市群城市扩张时空变化分析

Research on Spatial-temporal Changes of Urban Sprawl in Central Plains Urban Agglomeration Based on Multi-source Nighttime Light Data

探究中原城市群的城市扩张时空变化规律,有利于重建其空间结构的发展过程,厘清发展脉络,把握未来发展趋势,优化城市群建设.通过整合DMSP/OLS、NPP/VIIRS夜间灯光数据和辅助数据,采用阈值二分法提取城市群城市建成区,进而统计夜间灯光数量、城市扩展动态度及景观格局指数,对城市扩张时空格局演变进行量化分析.结果表明:(1)研究期内中原城市群城市夜间灯光总量稳步提升,灯光距平值区域化明显,郑州大都市圈处于领先地位;(2)城市面积增长了2.15倍,扩展动态度稳定在5%~6%之间,处于城市化的前期阶段,呈阶段性波动增长趋势;(3)灯光数据提取的城市建成区斑块呈现出中心-外围圈层式空间扩张结构的特征,城市扩张在原有基础上填充连片发展;(4)城市建成区斑块数量增长了1.97倍,形状指数在8%~9%之间,复杂程度加深,中小城市兴起并不断发展壮大,中心城市郑州市的首位度不断提升,极化作用明显,辐射带动周围城市发展,城市群趋向集聚化、一体化.

Exploring the spatial-temporal variation law of urban sprawl is conducive to rebuild the development process of its spatial structure,clarify the development context,grasp the future development trend and optimize the construction of urban agglomeration.Through the integration of DMSP/OLS,NPP/VIIRS nighttime light data and auxiliary data,the dichotomy of threshold is used to extract the built-up area and then the number of nighttime lights,urban expansion dynamics and landscape pattern index are counted to quantitatively analyze the spatial-temporal pattern evolution of urban sprawl.The results shows that:(1)During the study period,the total amount of nighttime light in Central Plains Urban Agglomeration increased steadily,but the growth rate slowed down;the anomaly light intensity was obviously regionalized,and Zhengzhou metropolitan area was in the leading position;(2)The build-up area increased by 2.15 times,and the expansion dynamic degree was stable between 5%and 6%,which was in the early stage of urbanization,showing a fluctuating growth trend;(3)The urban built-up area patches extracted from the light data show the characteristics of the circle spatial expansion structure dominated by the existing cities,and the urban expansion is filled with continuous development on the original basis;(4)The number of urban built-up area patches has increased by 1.97 times,the shape index is between 8%and 9%,and the complexity is deepening.Small and medium-sized cities are rising and growing,and the degree of primacy of Zhengzhou is increasing,polarization is obvious,radiation drives the development of surrounding cities,and urban agglomerations tend to agglomerate and integrate.