关键词: 中国, 三大层级城市群, 绿色发展, 投影寻踪模型, 时空演化

Abstract:

Green development is becoming increasingly important. The Fifth Plenary Session of the 18th CPC Central Committee established green development as an important development concept of the 13th Five-Year Plan (2016-2020). Urban agglomerations in China that perform as core areas are likely to play vital roles in the promotion of green development. This study focuses on Chinese urban agglomerations as the research object, and proposes a comprehensive index system for the assessment of green development. In addition, methods such as the projection pursuit model, Pearson correlation, coefficient of variation, and Theil index are used to measure the level of green development, spatial and temporal evolution characteristics, and heterogeneity in urban agglomerations of China. Results show that: (1) since 2005, the level of green development has been increasing, although by fluctuating amounts. When divided into layers, the green development results indicate a certain degree of hierarchical structure. Based on the overall performance of China's urban agglomerations over the past decade, their green development can be divided into five grades: highly advancing area, rapidly advancing area, steadily advancing area, preliminarily advancing area, and starting area. (2) The economic development element dominates the green development, followed by the social progress element, and then the ecological civilization element, which is improving gradually. Different levels of urban agglomerations show diverse characteristics at different stages when it comes to the evolution of dominant element. National urban agglomerations are dominated by economic development element, the dominant element in regional urban agglomerations is complex, and the provincial ones generally lack dominant element. Besides, there are also significant differences in the same hierarchy urban agglomeration. (3) The green development level of urban agglomerations mismatch the level of central cities and this phenomenon needs to be treated differently. (4) According to the Theil index value, differences in green development reveal a divergent trend, mainly owing to variations among the layers. (5) Finally, several policies are proposed to raise the level of such green development in China, including the exchange and cooperation among urban agglomerations, resource sharing, and the innovation and promotion of environmental policy.

Key words: China, three hierarchies of urban agglomeration, green development, projection pursuit model, spatial and temporal evolution