京津冀城市群城市用地扩张的空间特征及俱乐部收敛分析

Spatial Pattern and Club Convergence Analysis of Urban Expansion in Beijing-Tianjin-Hebei Urban Agglomeration

我国已进入城市化快速发展阶段,城市群是未来我国城市化的重要载体。以城市群为单元研究城市用地扩张的空间特征及内部分异规律,是提高城市化质量、实现城市群协调可持续发展的关键。论文以京津冀城市群为研究对象,基于空间效应的视角,采用1990、2000、2005和2010年4期遥感影像解译数据和城市扩张相关指数,综合运用探索性空间数据分析方法和空间计量经济学方法,分析了研究区1990—2010年间城市用地扩张的空间格局、区域分异及空间俱乐部收敛等特征。结果表明:1)京津冀城市群城市用地扩张迅速,新增城市用地围绕各市中心和高速公路沿线呈圈层和轴线式扩张;2)城市群内部城市用地扩张具有明显的空间集中性与分异性,并呈现显著空间自相关;3)通过Moran’s I指数对研究区进行内生分组,利用空间面板模型估计,结果发现:L-L和L-H地区城市扩张存在明显的空间俱乐部收敛,H-H地区虽收敛,但结果不显著,H-L地区不收敛。这些研究结果为进一步研究京津冀城市群地区城市扩张动力机制、促进城市理性扩张和京津冀协调一体化相关规划提供科学参考。

As the urbanization in our country has entered into a new rapid stage, urban agglomeration has become an important form of urbanization. Taking urban agglomeration as the subject, to research the spatial and internal differentiation characteristics of urban land expansion is the key to improve the quality of urbanization and achieve the coordinated and sustainable development of urban agglomeration. Based on four interpreted Landsat TM/ETM+images(obtained in 1990, 2000, 2005, and 2010, respectively) and urban expansion index, we apply spatial analysis and econometric models to study the spatial pattern, regional differentiation and space club convergence of urban expansion in Beijing-Tianjin-Hebei Urban Agglomeration during 1990-2010 from the perspective of spatial effect. Firstly, the interpretation of remote sensing images and the analysis of urban land-use changes show that from 1990 to 2010, urban land area increased about 4133 km2 in the urban agglomeration and the average annual expansion speed in 1990-2000, 2000-2005 and 2005-2010 was about 124, 172 and 407km2, presenting an accelerating tendency. Then the spatial variation of urban land expansion is explored by spatial buffer analysis. The result shows that urban lands expand rapidly around the central area and along the highway, presenting circular and axial modes of expansion.Moreover, the urbanization intensity index is employed to describe the spatial differentia of urban expansion, which is calculated and classified into five categories. The maps show that urban expansion presents obvious spatial concentration and differentiation. In addition,significant spatial autocorrelation has also been found by using Moran's I. Finally, the new concept of the spatial club convergence model is introduced into land expansion study. The spatial panel data analysis found space club convergence in L-L, L-H and H-H regions, and the convergence in L-L and L-H regions being significant(P<0.001). Nevertheless, the H-L region has not converged. It concludes that setting new core cities among slowly development area will have a positive effect on neighbors. This analysis can be used in further studies on expansion mechanism of urban agglomeration, and provide the government with scientific reference on rational urban expansion and integrated planning of Beijing-Tianjin-Hebei Urban Agglomeration.