The spectrum of metropolitan areas across the world, and detection of potential metropolitan areas with Chinese characteristics
Authors:   Peking University, Lu Qing ,   China, Xu Liyan ,   Peking University; China, Cai Zhen ,   Urban Space Planning and Architectural Design CO., LTD; China, Peng Xiao ,   Peking University; China
Published: August 2021

When people talk about the Metropolitan Area (MA), they mean differently in different parts of the world with different contexts. Based on its spatial extent, internal structure, socio-economic function, and network characteristics, an MA can refer to various entities from a metropolis to a Megacity-region. In an effort to clarify the MA concept, we review the origin of the MA concept and its development in various parts of the world, especially the United States, Japan and China, so as to propose a spectrum of MAs, and their relationship with specific human and natural geographical contexts. Particularly, we find MAs in China typically have a unique three-circle structure, which is composed of a core circle, a commuting circle, and a functional metropolitan circle. By international comparable standards which include factors such as population density, facility density, and economic activity intensity, and adjusted with reasonable context-dependent considerations in China, the three circles are designated as follows: the spatial extent with the highest development intensity and assuming a central regional role is identified as the core circle; the districts and counties around the core circle with a commuting rate greater than 10% are identified as the commuting circle; and the districts and counties within an one-hour accessible zone are identified as the functional metropolitan circle. To test the model, we utilize eight sources of big data covering ecological background, population, economy, transportation, real estate, land use, infrastructure, and culture characteristics, and with a fusion analysis of the data we show how the factors combined give rise to the three-circle structure in typical Chinese MAs, and why the combination of the same factors in the US and Japanese contexts works otherwise to fill different niches in the spectrum of MAs mentioned above. For a further inquiry, within the framework of the same model and using the same dataset, we identify 32 cities from all 338 prefecture-level cities in China that would qualify as an MA or potential MA, which we call “the Metropolitan Areas with Chinese Characteristics”, and designate the spatial extent of the three circles within each of the MAs. Additional analyses are also conducted to locate the main development corridors, key growth poles, and currently underdeveloped regions in each of the MAs. We conclude the paper with discussions of potential challenges of MA development in China vis-a-vis current policies, such as cross-administration collaboration between jurisdictions within the same MA, and cross-scale collaboration between MAs, cities, and city groups. Placing the research in the global context, and considering the vast similarities between China and other developing countries in terms of population density, land resources, urbanization level, and socio-economic development status in general, we argue that China’s model of MAs may be also applicable to other developing countries. Therefore, this research may shed lights to planning researchers and practitioners around the world, especially in developing countries in understanding the development conditions of MAs in their own contexts, and also in methods for identifying and planning potential MAs to achieve their specific policy objectives.