基于交通可达性的广佛都市区城市扩展的模拟与分析

可达性是连接土地利用与交通建设的关键环节,对城市扩展具有指向性。利用Auto-Logistic回归的CLUE-S模型,预测区域发展与交通规划两种情景下2020年广佛都市区的城市扩展,分析了1982~2020年交通可达性格局演变与城市扩展特征,并在此基础上揭示二者的耦合关系。结果表明：CLUE-S模型在城市扩展上具有较好的预测能力,且加入可达性因子有助于提高模拟精度;1982~2020年广佛都市区空间和时间可达性格局由双核心圈层结构演变为单核心圈层结构,且时间可达性格局有明显的交通主干道指向性;城市扩展强度与扩展差异逐渐拉大,预测2020年扩展区域集中在白云与花都交界处、天河黄埔一带、顺德部分乡镇;都市区由无序扩张转变为交通指向性,随着可被开发的土地的减少,交通指向性的影响减弱;初期的城市用地规模越大,交通可达性提高越显著,但随着交通基础设施先行建设的开展,城市规模对交通可达性的正向影响减弱。未来侧重于完善站点的公共配套设施和提高土地利用效率等方面。

Simulation of Urban Expansion in Guangzhou-Foshan Metropolitan Area Under the Influence of Accessibility

Accessibility is a key indicator connecting urban expansion and traffic infrastructure construction, which could reveal the potential development of metropolitan areas. The Conversion of Land Use and its Effects at Small regional extent (CLUE-S) and Auto-Logistic regression models were used to simulate urban expansion of the Guangzhou-Foshan metropolitan area in two scenarios, the regional development scenario and transportation planning scenario. Based on the evolution pattern of transportation accessibility and characteristics of urban expansion, the interaction between transportation accessibility and urban expansion was revealed. The results from the modified CLUE-S model showed better goodness of fit by adding accessibility indicators. The evolution patterns of the shortest space and time accessibility are all changing from a dual-core structure (1982) to a single-core structure—located within the Guangzhou City center during 1995-2020, especially the spatial pattern of the shortest time accessibility which is closely related to the main roads. Indexes of urban expansion intensity and expansion differentiation are increasing year by year. The city centers in the study area have almost been developed, with varying degrees of extension to Huadu, Panyu, Zengcheng, and other surroundings. Accessibility has an increasing negative impact on urban expansion. However, with traffic accessibility improved, the variation of accessibility has a declining positive effect on urban expansion; and the impact of urban expansion on variations of traffic accessibility is shifting from negative to positive effects. In the future, more attention should be given to improving land use efficiency and completing public service facilities around traffic stations.