佳文速递(3月） | 最新城市发展研究精选(英）

Spatiotemporal differentiation and influencing mechanism of urban expansion in the Yangtze River Economic Belt, China

ZHANG Min, YANG Liya, HU Zhuowei, YANG Ziqing

Abstract: Nowadays, the disordered expansion of urban land has become an important problem on China's urbanization. Urban population growth is widely recognized as a crucial driver of urban spatial expansion. Therefore, it is necessary to clarify the spatiotemporal differentiation characteristics of urban expansion and understand the relationship between urban population size and urban expansion. Based on Landsat TM/OLI remote sensing images and socioeconomic statistics data, this paper identified the urban land in the Yangtze River Economic Belt (YREB), China, between 1990 to 2020. This was achieved by combining object-oriented automatic extraction and human-computer interaction visual interpretation. The study then examined the spatiotemporal differentiation characteristics of urban expansion at difference scales using expansion speed, expansion difference index, kernel density analysis and spatial autocorrelation. Finally, the relationship between urban population size and urban expansion in different regions was investigated using the Two-way Fixed Effects Model. The main results are as follows: (1) After 2015, urban expansion speed decreased significantly in different parts of the YREB. Moreover, the time series characteristics of urban expansion in the cities of the upper and middle reaches were found to be different from those in the lower reaches. The upper reaches had higher expansion speed than the middle reaches after 2010. Spatially, the urban expansion in the YREB shows significant spatial heterogeneity. High-speed expansion areas have shifted from east to west, and the differences in urban land scale between the upper-middle and the lower reaches tend to converge. Urban expansion in the lower reaches exhibits strong spatial dependency, while in the middle-upper reaches, there is no significant spatial autocorrelation. (2) The relationship between urban population size and urban expansion differs significantly among different regions. The upper reaches show a negative correlation, while the middle-lower reaches exhibit a "U-shaped" relationship. This indicates that there is no obvious over-expansion of population size in the upper reaches, whereas there is in the middle-lower reaches. Residents in the middle reaches have demonstrated a higher sensitivity to urban comfort and quality of life. Finally, the study provides regional policy recommendations, aiming to offer scientific references for targeted urban policies and promote high-quality urban development.

Key words: urban expansion; spatiotemporal differentiation; urban population size; fixed effects model; urban expansion difference index; Yangtze River Economic Belt

Keywords: urban resilience; spatiotemporal evolution; influencing factors; East China Sea coastal zone

Key words: jobs-housing balance, excess commuting, commuting efficiency, Shanghai

Evolution of industrial comparative advantages and its driving mechanism of knowledge flow of cities in the Yangtze River Delta under the background of digital economy

WANG Tengfei, MA Renfeng, ZHUANG Rulong

Abstract: Many evolutionary economic geography studies emphasize the role of local capabilities in industrial development based on the path dependence theory. With the rapid development of new-generation information technology and infrastructure such as high-speed rail, the cross-regional flow of knowledge is becoming increasingly common and has a significant impact on regional and industrial evolution. Therefore, in the era of the knowledge economy, the multi-scale knowledge interaction network is crucial to the evolution mechanism of industrial comparative advantages. This study used patent citation big data and other statistical data, such as the total output value of the 2-digit manufacturing industry of 41 cities in the Yangtze River Delta in 2011, 2016 and 2021 and the Logit model to analyze the evolution of industrial comparative advantages and its knowledge dynamics. The research found that: 1) With the increasingly close intercity knowledge flow network in the Yangtze River Delta, the industries with comparative advantages in cities are becoming increasingly diverse as a whole. 2) Under the premise of controlling for local capabilities and other related variables, the evolution of urban industrial comparative advantages is also significantly influenced by the advantageous industries of cities with strong knowledge flows. In other words, a city is more likely to develop its own industrial comparative advantage in the specialized field of another city that has a strong knowledge correlation with it. 3) There is a significant knowledge network correlation in the evolution of the industrial comparative advantage structure of cities in the Yangtze River Delta. The stronger the knowledge flows, the higher the similarity of industrial comparative advantage structure between cities. To some extent, this study deepens the understanding of the knowledge dynamics and multi-scale related variety of the evolution of industrial comparative advantages in the digital economy era and helps to provide a theoretical basis for regional innovation and industrial upgrading policies.

Keywords: cross-regional knowledge flow; multi-locational knowledge dynamics; multi-scale related variety; evolution of industrial comparative advantage

Spatial network of industrial chains and their embodied carbon emissions in the Beijing-Tianjin-Hebei region

YANG Zihan, PENG Baoyu, SUN Jun*

Abstract: Under the background of collaborative development of Beijing, Tianjin and Hebei (BTH), interregional economic exchanges embody the division of labor in the industrial chain and the flow of embodied carbon emissions, thereby affecting the regional functional coordination and attribution of carbon emission responsibilities. Based on the Multi-Regional Input-Output (MRIO) Table of China in 2012 and 2017, this study constructed the industrial chain spatial network of the BTH region and analyzed the industrial links within the region and the embodied carbon emission flow relationships, in order to provide a decision-making basis for the coordinated development and for achieving the "dual carbon" goals of the region. The results show that: 1) The industrial division of the BTH region was clear, but the functional coordination was insufficient. There was also a strong dependence of industrial spatial connections and embodied carbon flow on heavy industry. The industrial chains in the construction field and equipment manufacturing are the main routes for interregional industrial linkages. 2) The production link of the manufacturing industry in the BTH region is weak. The upstream and downstream output of the core industrial chains is always higher than that of the midstream, and the spatial network linkage from manufacturing to producer services is weak. 3) From the perspective of spatial pattern of embodied carbon emissions, Beijing and Hebei are the areas that transfer and undertake the most embodied carbon emissions within the BTH region, and Tianjin's embodied carbon emissions account for the highest proportion of total carbon emissions in the region. On this basis, this article proposed policy recommendations including deepening the spatial integration of the industrial chain, and taking the lead in carrying out carbon tax and carbon emission trading pilot projects.

Keywords: coordinated industrial development; industrial chain spatial network; embodied carbon emissions; input-output method; Beijing-Tianjin-Hebei region

GU Jinyuan, YANG Dongfeng*

Abstract： The mobile communication technology and social media has been deeply embedded into people's daily life, affecting people's choices of leisure activities. However, there is still limited understanding of the spatial regularity characteristics of its impact, particularly due to the lack of empirical analysis utilizing specific quantitative indicators. Given that the layout of leisure spaces is closely linked to social equity, it is essential to obtain a better understanding of the emerging spatial patterns in order to improve residents' well- being. To address this gap, leisure check- ins on Xiaohongshu (a Chinese social media platform) and leisure Points of Interest (POI) in Dalian are used to measure the characteristics of these two types of leisure spaces in two dimensions: concentration and clustering, and at two scales: the main urban area and subdistricts. Various spatial analysis methods, including kernel density estimation, head/tail breaks, hot spot analysis (Getis-Ord Gi*), and DBSCAN (Density-Based Clustering), are employed to analyze the data. The findings are that: (1) Leisure checkins are mostly located in the urban central area, with a smaller distribution range and fewer hotspot cores; (2) At both the main urban area and subdistricts scales, the distribution of leisure check- ins exhibits lower concentration and clustering, with obvious "decentralized dispersion" characteristics. However, the degree of significance of these features varies across different subdistricts; (3) The majority hotspots of leisure check-ins are located in traditional hotspots, with a few emerging in expansion of urban central area or regions with unique features, such as historic urban landscape district and marina space; (4) The distribution patterns of leisure checkins can be grouped into four types based on differences in subdistricts' concentration and clustering ratio: "original center cluster type", "original center scattered type", "new center scattered type", and "no center scattered type". The subdistricts with these different distribution patterns exhibit differences in functionality, location, and other characteristics. This study analyses the behavioral processes of leisure activities under the influence of social media through the lens of Actor- Network- Theory. Based on the fundamental principles of temporal geography and differences between "space of places" and "space of flows", it is argued that social media engenders a novel "local order" of leisure pursuits, marked by a desire for spatial exploration. This new order reflects the impact of "space of flows" based on virtual connections on "space of places" based on physical presence, which strengthens the role of node attractors, reduces the constraints of accessibility at micro scales, and increases the flexibility of location.

GAO Feifan, LIU Yi*, LI Zhigang