Study On The Agglomeration Effect Of Manufacturing Industry And Its Relationship With Ecological Efficiency In Urban Agglomeration Of Yangtze River Economic Belt Under The New Development Pattern

According to the 20 th National Congress Report,one of the important measures to promote the construction of a new development pattern is to rely on urban clusters and metropolitan areas.The focus should be on the development of the real economy,especially in promoting the high-end,intelligent and green development of manufacturing.Such efforts will help to fundamentally improve the ecological environment and achieve the goal of a beautiful China.It can be seen that coordinating the relationship between economic development and ecological protection is the direction to achieve the above goals.In the 21 st century,the Yangtze River Economic Zone,the Yangtze River Economic Zone has become the main industrial cluster in China,and the economic benefits brought by manufacturing as a pillar industry and its impact on the ecological environment can not be ignored.Therefore,this thesis aims to clarify the temporal and spatial evolution of manufacturing agglomeration level and ecological efficiency of urban agglomerations in the Yangtze River Economic Zone and the relationship between them,and explore how to realize the high-quality development of urban agglomerations in the Yangtze River Economic Zone under the new development pattern and achieve the win-win goal for both economic development and environmental protection.Based on the new development concept,this study analyzes the temporal and spatial evolution characteristics of manufacturing agglomeration degree and ecological efficiency level from the perspective of industrial agglomeration effect,and constructs an empirical analysis framework of the influencing factors of ecological efficiency level and the relationship between manufacturing agglomeration degree and ecological efficiency level.In the empirical analysis,based on the panel data of 73 cities in the Yangtze River Economic Zone from 2010 to 2020,firstly,the agglomeration degree and ecological efficiency level of urban manufacturing industry are calculated by using the location entropy method and SBM-DEA model respectively,and the temporal and spatial evolution characteristics are analyzed by combining ARCGIS software.Then,the geographical weighted model and the threshold effect model are constructed respectively to study the spatial heterogeneity of the influencing factors of ecological efficiency of the Yangtze River Delta,the middle reaches of the Yangtze River and the ChengduChongqing urban agglomeration in 2020,and to explore the nonlinear relationship between the degree of urban manufacturing agglomeration and the level of ecological efficiency.Our study found that:(1)Manufacturing clusters can promote technological improvement and environmental improvement through three cluster effects: external economies of scale,cost savings and knowledge spillover,thus enhancing the ecological efficiency level of urban agglomerations.(2)The trend of manufacturing agglomeration is obvious,but it has urban differences.During the study period,they all showed a trend of slow decline first and then rising,with little fluctuation during the period,and the agglomeration level in the eastern region was significantly higher than that in the cities in the western region.At the same time,there are significant differences in the level of ecological efficiency among cities.Only the Yangtze River Delta urban agglomeration is higher than the average level of the Yangtze River Economic Zone,and the other two urban agglomerations are lower than the average level.(3)There are significant spatial heterogeneity in the influencing factors of urban ecological efficiency,and manufacturing agglomeration has a negative effect on the level of urban ecological efficiency,especially on the cities in the eastern part of the Yangtze River Economic Zone in 2020.Among them,innovation and sharing have a significant positive impact on urban ecological efficiency,especially in the more developed areas of the Yangtze River Delta urban agglomeration.Coordination and opening up have two effects on urban ecological efficiency,which can promote the ecological efficiency of most cities,but also inhibit the ecological efficiency of other small cities.(4)According to the threshold effect model,there is an inverted "U" relationship between the level of urban manufacturing agglomeration and its ecological efficiency in the Yangtze River Economic Zone.Finally,some suggestions are put forward.From the industrial perspective,we should actively adjust the industrial structure,promote the optimization and upgrading of the industrial structure,optimize the allocation of resources,and make the manufacturing industry bigger and stronger.We should develop according to local conditions and strengthen the construction of ecological civilization under the new development pattern due to the remarkable spatial heterogeneity of cities.Overall planning,relying on urban agglomerations to promote coordinated regional development,strengthen exchanges and cooperation between regions,and realize the overall high-quality development of the Yangtze River Economic Zone.