基于地理探测器的乌鲁木齐城市扩张特征与时空驱动因素分析

Urban expansion and its temporal and spatial driving forces of Urumqi based on geo-detector method

新时代我国城市发展内外环境明显变化,城市扩张特征和驱动机制也呈现出新特点。以乌鲁木齐市为例,描述1990—2018年城市建设用地扩张特征,利用地理探测器研究扩张时空机制,重点分析2010年以后扩张新特点。结果表明:(1)乌鲁木齐建设用地由1990年的84.37 km^(2)增加到2018年的361.91 km^(2),城市形态由南北带型演变为"T"字型结构,城市形态空间紧凑度逐渐下降;城市扩展速度稳定,扩展强度逐渐加强。城市扩张的"核心-边缘"结构经历"增强-减弱-增强"的时空变化过程。(2)城市建设用地扩张时间维度主要受人口规模、产业规模和政府推力的影响,其中人口规模作用最大,产业规模中第二产业作用略高于第三产业作用效果,2010年以后,政府推力对乌鲁木齐市城市扩张产生加速作用。(3)空间维度来说,交通类和商业类空间要素是驱动城市空间扩张的主要因素,随着时间推移,城市扩张的空间动力由少数关键因子驱动转变为多因子共同驱动。

Urban spatial expansion is a classic topic for urban geography,playing an increasingly important role in scientific research and government management.As the internal and external development environments of China’s urban areas have changed significantly in the new era,urban expansion and its driving mechanism were also shifted by new factors.This paper,taking Urumqi(a city in northwest China)as an example,described the characteristics of urban construction land expansion and expounded on the spatiotemporal expansion mechanism using the Geodetector method.The results are as follows:(1)Over the past 30 years,the construction land area in Urumqi increased from 84.37 to 361.91 km^(2).We constructed an urban space compactness index to reflect the rationality of the urban spatial boundary shape.The urban space compactness index gradually decreased over the past 30 years.This indicated that the spatial distribution is more reasonable and more efficient in the process of urban expansion.The urban expansion speed rate is 5.34%,and the urban expansion intensity rate increased from 3.57%to 8.79%.Urban expansion had a"core-periphery"structure,and its core agglomeration extent changed in different periods.(2)Urban expansion is mainly influenced by three factors:population scale,economic scale,and government policy.Population and economic agglomeration have the greatest effect on urban expansion.In economic terms,the secondary sector of the urban economy plays a slightly larger role than that of the tertiary sector on urban expansion.After 2010,new government policies accelerated urban expansion in Urumqi.(3)Transportation and commercial locations were the main spatial driving factors of urban expansion.The effects of single spatial driving factors gradually weakened,whereas the interactive effects of double spatial driving factors gradually strengthened over time.In the future,comprehensive simulations of urban expansion and resource and environmental effects should be further studied for the cities in western China.