Abstract:

The concept of megalopolis, since its original inception six decades ago, has inspired many new terms that mainly describe large-scale urbanized forms such as megaregions and polycentric urban regions. However, recent studies have increasingly focused on the two key functions that megalopolises act as an incubator of new ideas and trends and as a hub that articulates knowledge exchange at the megalopolitan, national, and global scales. While the recent studies have mainly analyzed the functional aspects of megalopolis based on China's Yangtze River Delta region, this paper investigates the evolving process and mechanisms of knowledge collaboration within and beyond Guangdong-Hong Kong-Macao Greater Bay Area (GBA) - one of the most promising and vibrant megalopolises in China. In addition, the GBA megalopolis is unique because it contains Hong Kong and Macao, which have a different political system from China's mainland. Drawing upon a dataset of publications that were indexed in Web of Science Core Collection during the 1990-2016 period, this paper uses the Gini coefficient to measure the degree of knowledge polycentricity of the GBA megalopolis. Here, knowledge polycentricity is further classified into attribute polycentricity of knowledge production and functional polycentricity of knowledge collaboration within and beyond the GBA megalopolis. Whereas the attribute polycentricity refers to the distribution inequality of the total publications of GBA cities, the functional polycentricity represents the distribution inequality of GBA cities' knowledge collaboration at different geographical scales. Our empirical results show: (1) knowledge production of the GBA megalopolis as a whole has experienced a robust and continuous growth. The degrees of both attribute polycentricity and functional polycentricity have also been on the increase in general, although there are some fluctuations in early years and some deviations in recent years. During the ten years after Hong Kong and Macao returned to China (the 2000-2010 period), the degree of knowledge polycentricity of the GBA megalopolis especially enjoyed the fastest rise; (2) The degree of functional polycentricity decreased with the expansion in the geographical scales at which it is measured, confirming the findings of previous studies that functional polycentricity is scale-dependent. Moreover, we find that the degree of functional polycentricity becomes more fluctuated at the global scale while it tends to increase continuously at the megalopolitan scale; (3) The evolving process of knowledge polycentricity of the GBA megalopolis is influenced by institutional proximity, geographical proximity and status proximity between cities. Specifically, the mobility of researchers, the collaboration of universities and research institutes, and the coordination of local governments are three major forces promoting the evolution of knowledge polycentricity of the GBA megalopolis. Overall, the increasing knowledge polycentricity would be of significance for the GBA megalopolis to form a knowledge-driven region of collective collaboration.

Key words: polycentricity, megalopolis, Guangdong-Hong Kong-Macao Greater Bay Area, knowledge city, scientific cooperation, collaborative innovation, one country and two systems