Research on the Digital Economy's Impact on China's Economic Growth:Based on the Variations in Urbanization Levels Across China's Eastern,Central,and Western Regions and Sectoral Heterogeneity

This paper uses inter-provincial panel data from 2011 to 2017,a linear regression model,and a threshold model to conduct empirical analyses of the impact of the digital economy on China's overall economic growth and the three main sectors of industry.The paper then investigates the impact and effects the digital economy has had on the economic growth of the three main sectors of industry in China's eastern,central,and western regions.Finally,the paper investigates the most significant differences among the various regions and the threshold effects of urbanization levels on the relationship between the digital economy and economic growth.The findings indicate a significantly positive correlation between the digital economy and regional economic growth.Moreover,geographical factors notably influence this correlation.The digital economy exerts a positive effect on all sectors of industry.It may not substantially impact industrial development in regions with highly developed infrastructure.Regarding the other regions,the digital economy exhibits varying degrees of impact due to the differences in the specific indicators.The conclusion drawn by the threshold model is that the magnitude of the threshold effect correlates with geographic factors.No threshold effect was observed in the eastern region,while the threshold effect occurred in the central region when the urbanization levels for the provinces were below 0.6645.Similarly,the threshold effect was noted in the western region when the urbanization level was below 0.3931.Considering all of this,the study also offers policy recommendations that will help balance the regional development of digital economies,accelerate the digital transformation of traditional industries,enhance digital infrastructure construction,refine the formulation and implementation of data policy,and establish relevant incentive mechanisms.

Retrieval and Regional Distribution Analysis of Ammonia,Sulfur Dioxide and Nitrogen Dioxide in the Urban Environment Using Ultraviolet DOAS Algorithm

Aiming at the in situ and mobile observation of urban environmental air pollution,a portable instrument using ultraviolet spectrum retrieval algorithm was developed based on the basis of Differential Optical Absorption Spectroscopy(DOAS)and multiple-pass cell technique.Typical trace gas pollutants,NH3,SO2,and NO2,were explored using their optical spectral characteristics in deep ultraviolet wavelength range from 210 to 215 nm.The gas concentration was retrieved by Lambert-Beer’s law and nonlinear least square method.With an optimized optical alignment,the detection limits of NH3,SO2,NO2 were estimated to be 2.2,2.3,and 36.2 ppb,respectively.The system was used in carrying out some cruise observations in Chengdu,China.During the entire period,the polluted gases showed varied distribution and typical daily average concentrations ofNH3,SO2,NO2 were 23.2,3.5,and 106.0 ppb,respectively.The contributions from different sources were analyzed combined with the HYSPLIT model.Results show that the portable DOAS system is a convenient and effective tool for regional distribution measurement and pollution source monitoring.

China’s urban green innovation:Regional differences,distribution dynamics,and convergence

Urban green innovation(UGI)is essential to environmental protection,ecological conservation,and high quality economic growth.Using green patents,our study assessed the level of UGI of 287 Chinese cities at and above the prefecture level.Then,using the Dagum Gini coefficient,kernel density estimation(KDE),and con‐vergence models,we examined regional differences,distribution dynamics,and convergence of UGI across China.The study’s findings are as follows:(1)Overall,regional differences in UGI tended to narrow,and the main contributor to these differences was the difference between economic zones.(2)KDE showed that the level of UGI was rising,which was polarized within each economic zone.(3)The national UGI in economic zones other than the Northeast and Middle Yellow River Economic Zones featured significantσconvergence,while each economic zone showed absolute and conditionalβconvergence.

Surface Regional Heat(Cool) Island Effect and Its Diurnal Differences in Arid and Semiarid Resource-based Urban Agglomerations

With the rapid development of urban agglomerations in northwest arid and semiarid regions of China, the scope of the urban heat island(UHI) effect has gradually expanded and gradually connected, and has formed a regional heat island(RHI) with a larger range of impact to the regional environment. However, there are few studies on the heat island effect of urban agglomerations in arid and semiarid regions, so this paper selects the urban agglomeration of Hohhot, Baotou and Ordos(HBO) of Inner Mongolia, China as the study area. Based on the 8-day composite Moderate-resolution Imaging Spectroradiometer(MODIS) surface temperature data(156scenes in all) and land use maps for 2005, 2010, and 2015, we analyze the spatiotemporal distributions of regional heat(cool) islands(RH(C)I) and the responses of surface temperatures to land-use changes in the diurnal and interannual surface cities. The results showed that: 1) from 2005 to 2015, urban areas showed the cold island effect during the day, with the area of the cold island showing a shrinking feature;at night, they showed the heat island effect, with the area of the heat island showing a first decrease and then an increase.2) From 2005 to 2015, the land development(unutilized land to building land) brings the greatest temperature increase(ΔT = 1.36°C)during the day, while the greatest temperature change at night corresponds to the conversion of cultivated land to building land(ΔT =0.78°C) exhibited the largest changes at night. From 2010 to 2015, the land development(grassland to building land) bring the greatest temperature increase(ΔT = 0.85°C) during the day, while the great temperature change at night corresponds to the conversion of water areas to building land(ΔT = 1.38°C) exhibited the largest changes at night. Exploring the spatial and temporal evolution of surface urban heat(cool) islands in urban agglomerations in arid and semiarid regions will help to understand the urbanization characteristics of urban agglomerations and provide a reference for the formulation of policies for the coordinated and healthy development of the region and co-governance of regional environmental problems.

Urbanization Impact on Regional Climate and Extreme Weather:Current Understanding,Uncertainties,and Future Research Directions

Urban environments lie at the confluence of social,cultural,and economic activities and have unique biophysical characteristics due to continued infrastructure development that generally replaces natural landscapes with built-up structures.The vast majority of studies on urban perturbation of local weather and climate have been centered on the urban heat island(UHI)effect,referring to the higher temperature in cities compared to their natural surroundings.Besides the UHI effect and heat waves,urbanization also impacts atmospheric moisture,wind,boundary layer structure,cloud formation,dispersion of air pollutants,precipitation,and storms.In this review article,we first introduce the datasets and methods used in studying urban areas and their impacts through both observation and modeling and then summarize the scientific insights on the impact of urbanization on various aspects of regional climate and extreme weather based on more than 500 studies.We also highlight the major research gaps and challenges in our understanding of the impacts of urbanization and provide our perspective and recommendations for future research priorities and directions.

Characteristics of Regional Differentiation of Urbanization Development in Anhui Province

On the basis of connotation of urbanization,by using SPSS factor analysis and cluster analysis,we establish index system of urbanization development level and conduct quantitative analysis on development level of urbanization in 17 prefecture-level city of Anhui Province,in order to find out the differentiation pattern of regional space of urbanization development in Anhui Province based on these.The results show that Anhui's difference of urbanization gradient is prominent.Classification of three clusters shows that the pattern of status quo of urbanization development in Anhui Province is "dual-nucleus" and "two-stretches";classification of five clusters show that the pattern of status quo of urbanization development in Anhui Province is "one-core","one-strip" and "three-region".From five aspects,namely natural geography,transportation location,resources distribution,economic development and administrative system,we analyze the reason and influencing factors of differentiation of urbanization development in the region.The results of three clusters and five clusters show that there is great possibility that "dual-nucleus" changes into "individual-nucleus";"one-core" and "one-strip" may evolve into "one-group".We should foster the urban agglomeration in central Anhui;perfect structure system in the perspective of integration and fostering;strengthen infrastructure construction and regional coordination system;elevate comprehensive competitiveness and guide holistic development of regional economy;promote industrialization process and promote development level of urbanization.

DYNAMICS OF REGIONAL URBANIZATION IN FUJIAN COASTAL AREA

Since the economic reform in 1978, urban development in China has become much more rapid and the dynamic mechanisms of urbanization more diversified. The 'Bottom Up' strategy becomes as important as, or even more important than, the 'Top Down' strategy as the dynamic mechanisms of regional urbanization. On the basis of major theories of development economics and regional economics, this paper analyzes the major dynamic mechanisms of regional urbanization in coastal area of Fujian Province from 1978 to 1989, and describes quantitatively the territorial differentiation of regional urbanization process under two major dynamic mechanisms using principal componet analysis.

The Empirical Analysis of the Influence of Urbanization on Regional Economic Growth

After decades of development,China's economy has achieved remarkable achievement.One of the signals is the rise of Chinese cities.The process of urbanization and economic development are intertwined.In addition,China is in the important stage of economic transition because the current economic development in China has risen to the bottleneck period.Therefore,it is of great significance to study the influence of urbanization on regional economic growth,which will better guide the process of urbanization in China and help to give better policy recommendations.Based on the previous researches and theories,this paper selects relevant data and carries out the empirical research.The empirical results show that there is a strong spatial autocorrelation in China's economy,and the development of urbanization plays a very important role in promoting the economy.The specific manifestation is:with high science and technology level,huge education investment and fine city infrastructure,the city’s economic developments are obviously at high speed,and have the spillover effect to periphery area.In the end,this paper gives relevant policy implements on the problems of urban development in China.

Spatiotemporal Variations and Regional Transport of Air Pollutants in Two Urban Agglomerations in Northeast China Plain

Characteristics of air pollution in Northeast China(NEC) received less research attention in the past comparing to other heavily polluted regions in China.Spatiotemporal variations of six criteria air pollutants(PM10, PM2.5, SO2, NO2, O3 and CO) in Central Liaoning Urban Agglomeration(CLUA) and Harbin-Changchun Urban Agglomeration(HCUA) in NEC Plain were analyzed in this study based on three-year hourly observations of air pollutants and meteorological variables from 2015 to 2017.The results indicated that the annual mean concentrations of air pollutants are generally higher in the middle and southern regions in NEC Plain and lower in the northern region.Megacities such as Shenyang, Harbin and Changchun experience severe air pollution, with a three-year averaged air quality index(AQI) larger than 80, far exceeding the daily AQI standard at the first-level of 50 in China.The annual mean PM and SO2 concentrations decrease most significantly in NEC urban agglomerations from 2015 to 2017, followed by CO and NO2, while O3 shows a slight increasing trend.All the six pollutants exhibit obvious seasonal and diurnal variations, and these variations are dictated by local emission and meteorological conditions.PM2.5 and O3 concentrations in NEC urban agglomerations strongly depend on wind conditions.High O3 concentrations at different cities usually occur in presence of strong winds but are independent on wind direction(WD), while high PM2.5 is usually accompanied by weak winds and poor dispersion condition, and sometimes also occur when the northerly or southerly winds are strong.Regional transport of air pollutants between NEC urban agglomerations is common.A severe haze event on November 1–4, 2017 is examined to demonstrate the role of regional transport on pollution.

Impact of Anthropogenic Heat Release on Regional Climate in Three Vast Urban Agglomerations in China

We simulated the impact of anthropogenic heat release （AHR） on the regional climate in three vast city agglomerations in China using the Weather Research and Forecasting model with nested high-resolution modeling.Based on energy consumption and high-quality land use data,we designed two scenarios to represent no-AHR and current-AHR conditions.By comparing the results of the two numerical experiments,changes of surface air temperature and precipitation due to AHR were quantified and analyzed.We concluded that AHR increases the temperature in these urbanized areas by about 0.5℃-1℃,and this increase is more pronounced in winter than in other seasons.The inclusion of AHR enhances the convergence of water vapor over urbanized areas.Together with the warming of the lower troposphere and the enhancement of ascending motions caused by AHR,the average convective available potential energy in urbanized areas is increased.Rainfall amounts in summer over urbanized areas are likely to increase and regional precipitation patterns to be altered to some extent.

Creation of Regional Characteristics for Urban Wetland Park

Concepts of regional characteristics and urban wetland park were introduced, contribution factors and creation principles of regional characteristics of urban wetland park analyzed. And the creation techniques were introduced from three perspectives: respecting regional natural environment and loci features, inheriting regional cultures and showing spirit of the place, applying materials and technology reasonably. Flowing Water Park in Chengdu City, Sichuan Province, Xiazhu Lake Wetland Park in Huzhou City, Jinghu National Urban Wetland Park in Shaoxing City, and Xixi Wetland in Hangzhou City, Zhejiang Province, were taken for example to specify techniques of creating regional characteristics of urban wetland park.

Urban Spatial Expansion Characteristics in China’s Rapid Urbanization Region—A Case Study of SXC Region

Urban spatial expansion characteristics are the responses of urbanization acts on the geographical space. Analyzing the characteristics can reveal the process of urban expansion and mechanism which is one of useful methods to find out the sustainable land use strategy balancing development and protection. In this paper, two main methods have been deployed in analyzing the spatial expansion characteristics of rapid urbanization region. One is the expansion index method and the other is fractal dimension method. And the results show that town-level urban sprawl has increased in a non-linear way since 1985, and even the increments of the urban expansion intensity are fluctuated. Morphology transformation from scatter to concentration is common phenomenon in the process of urbanization in the towns. From the morphology point of view, downtowns are more homogenous than towns with less variation. The concentration is the leading development trend in downtowns. And the more distance from the downtown is, the more spatial pattern morphology will be observed. These characteristics indicate that macro-scale policies of economic development and land use management have great impacts on the formation and characteristics of spatial patterns of urban dynamic patterns.

Impact of Anthropogenic Aerosols on Summer Precipitation in the Beijing–Tianjin–Hebei Urban Agglomeration in China:Regional Climate Modeling Using WRF-Chem

The WRF model with chemistry （WRF-Chem） was employed to simulate the impacts of anthropogenic aerosols on summer precipitation over the Beijing-Tianjin-Hebei urban agglomeration in China. With the aid of a high-resolution gridded inventory of anthropogenic emissions of trace gases and aerosols, we conducted relatively long-term regional simulations, considering direct, semi-direct and indirect effects of the aerosols. Comparing the results of sensitivity experiments with and without emissions, it was found that anthropogenic aerosols tended to enhance summer precipitation over the metropolitan areas. Domain-averaged rainfall was increased throughout the day, except for the time around noon. Aerosols shifted the precipitation probability distribution from light or moderate to extreme rain. Further analysis showed that the anthropogenic aerosol radiative forcing had a cooling effect at the land surface, but a warming effect in the atmosphere. However, enhanced convective strength and updrafts accompanied by water vapor increases and cyclone-like wind shear anomalies were found in the urban areas. These responses may originate from cloud microphysical effects of aerosols on convection, which were identified as the primary cause for the summer rainfall enhancement.

Regional Differences of China′s Urban Expansion from Late 20th to Early 21st Century Based on Remote Sensing Information

This study investigated the regional differences of China′s urban land expansion from the late 1980s to the year of 2008, based on the spatio-temporal analysis of CLCD (China′s land cover/land use database) datasets which were mainly produced from remote sensing imagery data. A newly defined urbanization level index (UI), based on urban land area, is proposed to describe Chinese urban expansion process at 1 kilometer, provincial, regional, and na-tional scales, together with the absolute urban expansion index (UEa) and the relative urbanization expansion index (UEr). The results indicate that the percentages of total land area occupied by urban in the late 1980s, 1995, 2000, 2005, and 2008 were approximately 0.25%, 0.32%, 0.33%, 0.43% and 0.52% of China′s total land area, respectively. Between the late 1980s and 2008, the total urban expansion in the mainland of China was 2.645 × 104 km2, resulting in an annual urban expansion area of about 1322.7 km2/yr, with the UEr of 111.9%. This study also finds that there has been an obvious spatial gradient of urbanization ratio running from the east coast to the west inland, and the urbanization gaps among different regions have persisted over the past two decades. The study also reveals obvious temporal varia-tions of the urbanization rates. There was very little urban growth during the period of 1995-2000 due to the governmental policy factors.

URBAN REGIONAL STRUCTURES TRANSFORMATION AND SUSTAINABLE DEVELOPMENT: CASE STUDY OF NANJING MEGALOPOLIS

s: Since 1978, many changes have happened on the background of urban regional structure in China, such as the economy system restructuring, the social transforming including the population flow accelerating and social demand diversifying and individualizing, the political and economic systems reforms, the rise of the real estate market and the changing relationship between human and nature. From the macroscopic view, these changes make the national urban system to be a newer pattern with a widening gap among the cities in spite of the rising of the cities as a whole. At the same, the urban land use structures are changing with both the trends of intensification and diversification, and the trends of the regional diversification and the economic integration. Besides, urban structures with multiple centers are emerging in several metropolitan areas in China. These changes and trends mentioned above are confirmed by a case study of Nanjing City, a growing metropolitan area in east China. The case study also points out some problems in urban regional structure reforming, especially the poor social and ecological considerations. We should pay more attention to some ideas like balance of intensification and decentralization, development of suburban centers and a reasonable mixing of the functional activities to develop a sustainable urban regional structure.

System Dynamics-and its Use in Understanding Urban and Regional Development

System dynamics shows how the structure and policies in a system produce change through time. System dynamics deals with the internal processes that produce good and bad behavior in social, economic, and environmental systems. In a system dynamics study, one builds a computer model that acts out the behavior of the real system being represented. The computer model is then used to

Influence of Transportation Accessibility on Urban-rural Income Disparity and Its Spatial Heterogeneity

Transportation accessibility has been treated as an important means of reducing the urban-rural income disparity.However,only a few studies have examined the effects of different types of transportation accessibility on urban-rural income disparity and their spatial heterogeneity.Based on data from 285 prefecture-level(and above)Chinese cities in 2000,2005,2010,2015,and 2020,this study uses spatial econometric models to examine how highway accessibility and railway accessibility influence the urban-rural income disparity and to identify their spatial heterogeneity.The result reveals that highway accessibility and railway accessibility have‘coreperiphery’ring-like circle structures.The urban-rural income disparity exhibits strong spatial clustering effects.Both highway accessibility and railway accessibility are negatively associated with urban-rural income disparity,and the former having a greater effect size.Moreover,there is a substitution effect between highway accessibility and railway accessibility in the whole sample.Furthermore,these associations differ in geographic regions.In the central region,highway accessibility is more important in reducing the urban-rural income disparity,but its effect is weakened with the increase of railway accessibility.In the western region,railway accessibility has a larger effect on narrowing the urban-rural income disparity,and this effect is strengthened by the increase of highway accessibility.We conclude that improving transportation accessibility is conducive to reducing the urban-rural income disparity but its effect is spatial heterogenetic.Highways and railways should be developed in a coordinated manner to promote an integrated transport network system.

Dynamic Evaluation on Regional Tourism Competitiveness:Urban Agglomeration of Shandong Peninsula,Eastern China

The article establishes the appraisal index system for entire urban agglomeration and its interior cities individually,concretely including five aspects:driving forces for tourism development,the level of tourism development,tourism impacts,tourism economic connection and tourism contributions of different cities to the whole urban agglomeration.As tourism competitiveness has the characteristics of comprehensiveness,systematicness and dynamicness,the article attempts to apply the structural prediction means of system dynamics to evaluating tourism competitiveness,aiming to provide some research methods and analysis ideas for tourism competitiveness measurement and trends analysis in urban agglomeration.Taking Shandong Peninsula urban agglomeration as the study area,the article simulates and analyzes the tourism competitiveness trend of the whole region and its interior cities from 2005 to 2020,and the result reflects that integrated development and regional combination of tourism are important means to upgrade tourism competitiveness in this region.

Impact of regional human capital and urban sprawl on forest——based on a forest conservation model

Metropolitan cities in China have become a major economic hubs with an unprecedented increase of land use and decline of environmental resources. Based on a simple and abstract forest conservation model, this paper attempts to explain changes of forest resources caused by urban sprawl. Through the research, it is found that high level of regional human capital is beneficial to curb urban sprawl. In this vein the model presents the urban forest conservation cost strategy at the Nash equilibrium of varied discount factor and parameter control.

Coordinated Development of Urbanization and Animal Husbandry Industrialization in Western Regions of China

Animal husbandry industrialization and rural urbanization in western regions of China are not independent,but two aspects of development with mutual interaction. Animal husbandry industrialization provides material basis of progress in productivity for rural urbanization. In turn,rural urbanization provides development conditions,such as industry,technology,science,information,market,finance,transportation,communication,and social service,for animal husbandry industrialization. This paper analyzed existing problems and interaction between animal husbandry industrialization and rural urbanization in western regions are analyzed,and finally it came up with policy recommendations for coordinated development of animal husbandry industrialization and rural urbanization.