成渝城市群城市空间扩展冷热点格局演化趋势模拟

城市空间扩展作为城镇化在空间上最显著的特征,不仅可以衡量城市的城镇化水平,还可以对城市的可持续发展起到指导作用。以成渝城市群(Chengdu-Chongqing Urban Agglomeration, CCUA)为例,基于夜间灯光遥感数据,首先,分析了成渝城市群城市空间扩展的冷热点分布特征;其次,结合研究区域生态空间约束条件,构建了最小累积阻力面模型,模拟了成渝城市群城市空间扩展冷热点格局的演化趋势。结果表明:成渝地区空间扩展的冷热点在不同的时期体现出不同的特征。在1992～1996、1996～2002、2002～2009、2009～2015年4个时间段内,城市空间扩展的自相关性逐渐减弱,冷热点分布的全局特征逐渐趋于随机化,局部特征体现出城市空间扩展的多样性,具体表现为热点区域经历了"点状扩张-点环扩张-点轴扩张-轴带辐射"的格局转变过程。成渝城市群空间扩展的冷热点演化趋势在不同规模的城市扩张模拟中,热点区域不断增加。在城市空间扩展5%时,只有4个以成都、绵阳、达州、眉山为主的热点城市,当在城市空间扩展20%时,所有城市(共16个)其空间扩张强度均超过10%,发展成为城市空间扩展的热点区域。

Evolution of Cold-Hot Spot Pattern of Urban Expansion：A Case Study of Chengdu-Chongqing Urban Agglomeration

Urban spatial expansion is the most significant feature of urbanization in space. It can not only measure the level of urbanization in cities, but also guide the sustainable development of cities. This paper takes Chengdu-Chongqing urban agglomeration (CCUA) as the study area, based on the nighttime lighting data, first of all, it analyzes the urban spatial expansion of CCUA and the distribution characteristics of urban hotspots. Secondly, based on the ecological space constraints of the CCUA, the minimum cumulative resistance surface was constructed, and the evolution trend of the urban hotspot pattern of CCUA was simulated. The main conclusions are as follows: (1) The cold-hot spots of urban expansion in CCUA reflect different characteristics in different periods. In the four time periods, CCUA urban expansion shows a weak trend of spatial natural correlation, and the global features of the distribution of cold-hot spots became randomized. Reflecting the diversity of urban space expansion, the cold-hot areas of the city spread pattern experienced a “spot expansion-point ring expansion-point axis expansion-axis radiation” transformation process.(2) In the different scales simulation of urban expansion, the evolution trend of cold-hot spots in CCUA is the hot spot area becoming increasing. When the urban space expands by 5%, there are only four hot-spot cities based in Chengdu, Mianyang, Dazhou, and Meishan. When the urban space expands by 20%, all cities (16 in total) have a spatial expansion intensity exceeding 10%, and has become hot spots for urban space expansion.