China's Three Major Metropolitan Area: Radiation Range And Differences

Based on the "core-periphery" theory of New Economic Geography, this paper studies the three major city clusters centering respectively around three large ports, Shanghai, Hong Kong and Tianjin, using Chinese city-level panel data. We find that the relationship between a city's GDP per capita and its distance to the nearest port shows a cubic curve of "∽" shape in Pearl River Delta (PRD) and Yangtze River Delta (YRD). Within a certain distance from a major port when agglomeration effect dominates dispersion effect, the farther away from the core city, the lower a city's GDP per capita is. But as the distance is farther, the dispersion effect gets stronger. Thus, the first bottom of the "∽" shape has the weakest agglomeration effect compared with dispersion effect within some city cluster region, and thus can be interpreted as the scope of the city cluster, and the slope of the first section of the curve reflects the relative agglomeration effect, compared with dispersion effect of the core city. A major finding is that YRD's relative agglomeration effect is slightly stronger than that of PRD. Whilst city clusters around Bohai Sea remain as a city system where several port cities present agglomeration effects all together.