多中心城市群土地利用/覆被变化地学信息图谱研究——以长株潭城市群为例

多中心城市群具有交通网络发达、功能联系密切、空间多维复合等特征,其土地利用/覆被变化（LUCC）是一个相当复杂的过程。采用地学信息图谱方法,探索城市群LUCC数量结构与时空格局一体化耦合机理,研究用地变化与区域发展互动关系,有助于深入揭示多中心城市群土地利用时空演变规律,为同类城市群的国土空间规划和健康发展提供参考。本文以典型案例长株潭城市群为例,构建1995—2015年四个时期地学信息图谱,并耦合重心转移模型,在总体量化分析基础上,重点从城际与城乡视角深入解析城市群土地利用时空变化特征和一体化发展态势。研究结果表明：① 土地利用总体动态加速演变。四期建设用地扩张年动态度分别为1.06、4.10、2.21和7.39,转移强度动态增加,耕地和林地呈加速减少态势。② 城际与城乡地类图谱转移呈现多维演变。图谱“15（耕地→建设用地）、25（林地→建设用地）、45（水域→建设用地）”重心由株洲城区（Ⅰ 期）向长沙城区（Ⅱ 期和Ⅲ 期）再向湘潭城区（Ⅳ期）迁移,经历“相对均衡-长沙加速崛起-有机均衡”和“城市加速集聚-城乡相对均衡”演变过程。③ 近年来,城际转移强度差异缩小,转移结构分异增加,区域主体功能逐步凸显。同时,外围区县加速发展,城乡一体化水平明显提升。④ 城市群土地利用涨落势图谱与经济社会一体化发展高度耦合,同时耕地保护与高质量发展有待加强。

Geo-information Tupu process of land use/cover change in polycentric urban agglomeration: A case study of Changsha-Zhuzhou-Xiangtan urban agglomeration

Polycentric urban agglomerations are characterized by developed transportation networks, close functional connections and spatial multi-dimensional composition, and their land use/cover change (LUCC) is a complex process. By applying geo-information Tupu method to explore the coupling mechanism between LUCC quantity structure and spatiotemporal pattern as well as to examine the interactive relationship between land use change and regional development, this study will help us reveal the rules of spatiotemporal evolution of LUCC in polycentric urban agglomerations, and provide reference for the territorial spatial planning and sustainable development of similar urban agglomerations. In this paper, we take Changsha-Zhuzhou-Xiangtan urban agglomeration as an example, build the LUCC geo-information Tupu of four periods (1995-2000, 2000-2005, 2005-2010 and 2010-2015) from 1995 to 2015 and couple the gravity center transfer model. Then we analyze the spatiotemporal characteristics and integrated development trend of LUCC in urban agglomerations from the perspective of inter-city and urban-rural areas and based on overall quantities analysis. The results show that: (1) The overall dynamics of LUCC were accelerating. The annual dynamics of construction land expansion in four periods was 1.06, 4.10, 2.21 and 7.39, respectively, and the transfer intensity increased dynamically, while the cultivated land and forest land showed an accelerated decrease trend. (2) The Tupu of inter-city and urban-rural land transition presented a multi-dimensional evolution. The gravity center of Tupu "15, 25 and 45" firstly transferred from Zhuzhou urban area (Ⅰ period) to Changsha urban area (Ⅱ and Ⅲ periods), and then to Xiangtan urban area (Ⅳ period). The evolutionary process experienced a process of "relative equilibrium - Changsha accelerating rise - organic equilibrium" and "accelerated agglomeration of the city - relative equilibrium of urban and rural areas". (3) In recent years, the inter-city transfer intensity difference is reduced and the transfer structure difference is increased, and main function of the region is gradually highlighted. At the same time, the development of peripheral areas accelerated, and the level of urban-rural integration improved significantly. (4) The fluctuation Tupu of land use is highly coupled with the economic and social integration development; meanwhile, the cultivated land protection and high-equality development of urban agglomeration needs to be strengthened.