基于引力模型的城市区位潜力测度与区域双核结构刻画——以山东省济—青双核结构为例

Measuring the Potential of City Location and Picturing Regional Dual-nuclei Structure with Gravity Model: Evidence from Jinan-Qingdao in Shandong Province

区域双核结构是由中心城市和港口城市组成的一种空间结构现象,基于既有的双核结构理论研究,构建刻画这一地理现象的数理模型。研究方法是以空间相互作用引力模型作为区位潜力的测度,构建基于中心联系、门户联系、自身对外联系三部分的综合区位潜力函数,并运用山东省作为案例进行实证检验。结果表明:综合区位潜力函数结合最大引力线设定参数,能够有效刻画两种极限情境下的区位潜力分布,得出山东省城镇体系空间作用格局的真实情形介于双核与多核两种极限情境之间的结论,并且在区域双核结构向多核结构演变的过程中,新的中心最易出现在与中心门户连线的中垂线上,因为这一区域受到中心城市和门户城市相对均衡的辐射。

Regional dual-nuclei structure is a special spatial structure consisting a central city and a port city. According to the theories on regional dual-nuclei structure, this paper uses gravity model to measure the strength of spatial interaction between cities, which reflects the potential of city location. The distribution of this potential forms the picture of regional dual-nuclei structure. In this paper, firstly a function of location value was built, considering accessibility with the central city, the port city and other cities. Then, based on theoretical derivation, the distribution of location value in a specific dual-nuclei city system shows obvious dual-circled pattern, and the change of parameters in function can simulate different scenarios. At last, this paper used Jinan-Qingdao as experimental case to test the validity of this measurement method. According to two extreme scenarios, it could be concluded that the real pattern of city system in Shandong Province turned out to be on the situation between dual-nuclei and multi-nuclei.