数字经济与城市群协同发展：基于夜间灯光数据的研究

准确认识数字经济与城市群协同发展的关系，有利于拓展数字经济影响的评估视角，也为发挥数字经济和区域一体化的融合倍增效应提供有益思路。研究发现，数字经济时代城市群辐射带动区域协同发展的步伐正在加快，数据要素跨域流通打破了城市群内部和城市群之间的市场分割，助推城市群边界的有效扩大。数字经济促进城市群协同发展主要通过两个作用机制，一是推动创新主体跨城市跨区域进行合作创新，促进城市协同创新网络发育壮大；二是提升城市空间集中度，增强邻近空间范围内的城市要素集聚能力。数字经济的网络性、跳跃性及外部性特征放大了中心城市对外围城市的辐射带动作用和空间溢出效应，因此构建与数字经济相匹配的区域一体化协调机制和要素统筹配置机制正当其时。

Digital Economy and Urban Agglomeration Coordinated Development: A Research Based on Night-Time Light Data

Profound changes have taken place in China’s regional economic layout and spatial structure. As a major form of the new-type urbanization, the development pattern of urban agglomeration is in the ascendant. Urban agglomeration has become an important carrier and platform in leading China’s economic transformation and upgrading. To enhance the economic and population carrying capacity of the central cities and urban agglomeration, and to promote their roles as radiators and power-houses are the key to regional coordinated development during the 14th Five-Year Plan period. In recent years, with the boom in digital economy, the central and local governments have paid more and more attention to the development of digital economy. Whether the development of digital economy can strengthen the leading role of urban agglomeration and central cities and promote the coordinated development of regional economy is of great significance for the establishment of a “dual circulation” development pattern. Meanwhile, it is also an academic and practical topic that deserves in-depth research. Taking cities at prefecture level and above among China’s three largest urban agglomerations, the Beijing-Tianjin-Hebei agglomeration (BTHA), the Yangtze River Delta agglomeration (YRDA), and the Pearl River Delta agglomeration (PRDA) as research samples, this paper empirically tests the impact of digital economy on the coordinated development of urban agglomeration by using Spatial Dubin Model (SDM) and Panel Instrumental Variable Model.The innovation and marginal contributions of this paper are reflected in the following two aspects. First, perspective innovation. The paper evaluates the spatial impact of digital economy on the urban agglomeration based on empirical experience, clearly gives answers to whether digital economy can integrate multiple forces of factors, production and consumption, remove segmentation between cities caused by administrative division, and promote the effective expansion of urban agglomeration boundaries. In doing so, it not only expands the perspective of digital economy impact assessment but also provides useful ideas for effectively giving play to the leading role of urban agglomeration so as to compensate for the lack of spatial perspective in the current research of digital economy, which reflects the research depth to a certain extent. Second, method innovation. This paper employs the latest NPP-VIIRS global night-time light data to identify urban economic activities, and take the amount of annual news information in closely related entries of “digital economy” obtained by keyword retrieval and crawling on the Baidu search engine as a measure of the development of digital economy in cities. In this way, it not only expands the sample size but also effectively avoids the potential endogenous problems in the empirical research, which helps eliminate interference of some other factors. Therefore, this new method is helpful to test the causal effect of digital economy and urban agglomeration coordinated development.The main conclusions of this paper are as follows. Firstly, in the era of digital economy, the pace of regional economic development driven by urban agglomeration is accelerating. The most prominent feature is that the economic effects brought about by urban agglomeration begin to spread to non-urban agglomeration areas. Further observation of the geographical radius of urban agglomeration digital economy spillover shows that there is a dense area of digital economy spatial spillover within 200 km, and the spillover effect gradually decreases from about 300 km. Overall, the average distance of spatial spillover of digital economy is about 250 km.Secondly, there are two ways for the digital economy to promote the coordinated development of urban agglomeration. First, by means of the patent cooperation data at the micro level, it is revealed that digital economy can promote trans-city and trans-regional cooperation and innovation of innovative subjects, and an urban collaborative innovation network is forming, which enables closer connections between cities. Secondly, by improving urban spatial concentration, digital economy has made cities more attractive to gather surrounding population and industries, and the urban population agglomeration has increased within the adjacent space.Thirdly, in an era of digital economy, the central city plays a more important role. Specifically, the digital economy of central cities has a strong spatial spillover effect on the peripheral cities. Besides, central cities will have larger effects as the radiators and power-houses of their peripheral cities as digital economy connects different regions like a network, breaks geographical barriers and provides externalities shared by these regions. These findings provide direct evidences for further giving play to the role of digital economy as an impetus and strengthening the leading role of central cities and urban agglomeration in high-quality economic development.