Spatial-temporal evolution and driving factors of coupling between urban spatial functional division and green economic development: Evidence from the Yangtze River Economic Belt

It is of great significance to analyze coupling coordination feature between urban spatial functional division (USFD) and green economic development for the realization of regional high-quality sustainable development. However, few studies have investigated the coupling between USFD and green economic development. Therefore, based on the analysis of the coupling and coordination mechanism between USFD and green development, this paper innovatively calculates the indicators of USFD and green economic development of 108 cities in the Yangtze River Economic Belt (YREB) from 2009 to 2019. Moreover, we explore the spatiotemporal patterns, evolution characteristics of the coupling degree between the USFD and green economic development using the improved entropy method, coupling model, kernel density estimation and spatial autocorrelation method, and further analyzes the influence factors with the Tobit regression method. The study found that: 1) During the study period, the development level of USFD and green economy in the YREB showed a fluctuating upward trend, but the development level was still low and there was a large space for improvement. 2) During the study period, the coupling coordination degree of USFD and green economy development in the YREB shows a favorable development trend of fluctuating growth, but it is still in the stage of moderate coupling and coordination development. The coupling degree shows a trend of polarization and the phenomenon of "high-value difference and low-value convergence " over time. 3) The spatial distribution of coupling coordination degree in each region is obviously different, and the middle and lower reaches are significantly higher than the upper reaches, and there are "club convergence " phenomenon and obvious H-H and L-L spatial agglomeration characteristics. 4) Technological innovation, industrial structure and physical capital have a significant positive impact on the coupling degree of the two systems, while human capital has a restraining effect on the growth of the coupling degree. There is heterogeneity in the extent and direction of the influence of each factor on the degree of coupling between the three agglomerations. These findings have significant policy implications for the region to facilitate rational division of labor and coordinated development of the green economy.