scholarly journals Delineating the Spatial Boundaries of Megaregions in China: A City Network Perspective

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Wei Chen
Keyword(s):  
Global Economy ◽  
Eastern China ◽  
Analytical Framework ◽  
Yangtze River Delta ◽  
River Delta ◽  
Urban Systems ◽  
Highway Traffic ◽  
Functional Regions ◽  
Spatial Configurations ◽  
The City

Globalization and informatization have significantly reshaped the map of the global economy. Mega cities and regions have become the battlegrounds in the interplay between globalization and localization, with megaregions becoming the most globally significant spatial configurations in this regard. However, academics and government departments disagree on how to define the spatial boundaries of megaregions. In this study, on the basis of highway traffic flow data between cities, we integrate the community detection and core-periphery profile algorithms to characterize the city networks in China and identify the city groups and delineate the core structures of city groups, which are the underlying megaregional structures in China. Based on this, we identify 21 megaregions among city groups in China, including the Yangtze River Delta, Pearl River Delta, Beijing-Tianjin-Hebei, and Chengdu-Chongqing megaregions, and preliminarily delineate their spatial boundaries. On the whole, there are spatial differences among China’s megaregions to a certain extent. Central and eastern China have numerous, large, and a high density of megaregions, while the western region has relatively few megaregions. The latter also differs notably from mature megaregions in terms of rank sizes, urban systems, and functional divisions of labor. Generally, this study develops a novel analytical framework for identifying the functional regions of megaregional space in China from a perspective of relational geography, with methodological implications for other fields of inquiry.

scholarly journals Interpreting the <sup>13</sup>C  ∕ <sup>12</sup>C ratio of carbon dioxide in an urban airshed in the Yangtze River Delta, China

2017 ◽  
Vol 17 (5) ◽  
pp. 3385-3399 ◽  
Author(s):  
Jiaping Xu ◽  
Xuhui Lee ◽  
Wei Xiao ◽  
Chang Cao ◽  
Shoudong Liu ◽  
...  
Keyword(s):  
Mole Fraction ◽  
Yangtze River ◽  
Eastern China ◽  
Yangtze River Delta ◽  
River Delta ◽  
Atmospheric Co2 ◽  
The Tibetan Plateau ◽  
Natural Ecosystems ◽  
Carbon Cycles ◽  
The Yrd

Abstract. Observations of atmospheric CO2 mole fraction and the 13C ∕ 12C ratio (expressed as δ13C) in urban airsheds provide constraints on the roles of anthropogenic and natural sources and sinks in local and regional carbon cycles. In this study, we report observations of these quantities in Nanjing at hourly intervals from March 2013 to August 2015, using a laser-based optical instrument. Nanjing is the second largest city located in the highly industrialized Yangtze River Delta (YRD), eastern China. The mean CO2 mole fraction and δ13C were (439.7 ± 7.5) µmol mol−1 and (−8.48 ± 0.56) ‰ over this observational period. The peak monthly mean δ13C (−7.44 ‰, July 2013) was 0.74 ‰ higher than that observed at Mount Waliguan, a WMO (World Meteorological Organization) baseline site on the Tibetan Plateau and upwind of the YRD region. The highly 13C-enriched signal was partly attributed to the influence of cement production in the region. By applying the Miller–Tans method to nighttime and daytime observations to represent signals from the city of Nanjing and the YRD, respectively, we showed that the 13C ∕ 12C ratio of CO2 sources in the Nanjing municipality was (0.21 ± 0.53) ‰ lower than that in the YRD. Flux partitioning calculations revealed that natural ecosystems in the YRD were a negligibly small source of atmospheric CO2.

scholarly journals Spatial-Temporal Differences and Influencing Factors of Tourism Eco-Efficiency in China’s Three Major Urban Agglomerations Based on the Super-EBM Model

2020 ◽  
Vol 12 (10) ◽  
pp. 4156
Author(s):  
Yiyang Sun ◽  
Guolin Hou ◽  
Zhenfang Huang ◽  
Yi Zhong
Keyword(s):  
Pearl River Delta ◽  
Yangtze River ◽  
Eastern China ◽  
Yangtze River Delta ◽  
Tourism Industry ◽  
External Factors ◽  
River Delta ◽  
Policy Implications ◽  
Pearl River ◽  
Urban Agglomerations

On the background of climate change, studying tourism eco-efficiency of cities is of great significance to promote the green development of tourism. Based on the panel data of the three major urban agglomerations in China’s Yangtze River Delta, Pearl River Delta, and Beijing–Tianjin–Hebei region from 2008 to 2017, this paper constructed an evaluation index system and measured the tourism eco-efficiency of 63 cities by using a hybrid distance model called Super-EBM (epsilon-based measure). We compared the spatial and temporal evolution characteristics of tourism eco-efficiency in the three urban agglomerations. Furthermore, the internal factors influencing tourism eco-efficiency were explored through input–output redundancy, and the external factors were analyzed by a panel regression model. The results indicate that the tourism eco-efficiency of the three urban agglomerations in China generally shows a decreasing-rising-declining trend. Among them, the Yangtze River Delta has the highest eco-efficiency, followed by the Pearl River Delta, and the lowest in the Beijing–Tianjin–Hebei region. Moreover, there is a certain gap within each urban agglomeration. The redundancy input of labor and capital is the main internal cause of low eco-efficiency. Among the external factors, the status of the tourism industry and the level of urbanization have a positive effect on eco-efficiency, while the level of tourism development, technological innovation and investment have a negative impact on it. In the future, we must attach great importance to the development quality and overall benefit value of the tourism industry so as to achieve green and balanced development of the three major urban agglomerations in eastern China. Based on the above conclusions, this paper puts forward targeted policy implications to improve the tourism eco-efficiency of cities.

Locating the interstitial island: Integration of Zhoushan Archipelago into the Yangtze River Delta urban agglomeration

Urban Studies ◽  
2020 ◽  
pp. 004209802093798
Author(s):  
Huan Zhang ◽  
Adam Grydehøj
Keyword(s):  
Yangtze River ◽  
Urban System ◽  
Yangtze River Delta ◽  
River Delta ◽  
Urban Agglomeration ◽  
Urban Systems ◽  
The Yangtze River ◽  
Zhoushan Archipelago ◽  
The Yangtze River Delta ◽  
Urban Functions

Amidst the debate concerning how to interpret the emergence of new forms of urbanism in today’s world, little attention has been given to urban interstices – the inter-urban boundary areas and interface zones that facilitate exchange between and within vast urban systems. The present paper considers how place is made and developed at these interstices, which frequently provide essential urban functions but are also frequently regarded as rural. We explore this topic through the case of Zhoushan Archipelago (Zhejiang Province, China), an interface zone both between cities within the Yangtze River Delta urban agglomeration and between the Yangtze River Delta urban agglomeration and other megaregions. Like many islands, Zhoushan Archipelago has long been conceptualised as peripheral to the urban yet has simultaneously performed vital urban functions. The paper uses this case to shed light on what interstitiality (in-betweenness) means in today’s urbanism, both for the people living ‘in-between’ and for the wider urban system.

Exploring the trends and potential drivers of surface ozone in eastern China in 2015-2018

2020 ◽  
Author(s):  
Ning Yang ◽  
Yanru Bai ◽  
Yong Zhu ◽  
Nan Ma ◽  
Qiaoqiao Wang
Keyword(s):  
Air Quality ◽  
Transport Model ◽  
Surface Ozone ◽  
Eastern China ◽  
Yangtze River Delta ◽  
River Delta ◽  
Pearl River Delta Region ◽  
Chemical Transport Model ◽  
Delta Region ◽  
Almost All

&lt;p&gt;In the last six years, China has experienced significant improvement in air quality due to great emission reduction efforts. However, ozone concentrations are still slowly increasing in three major regions of eastern China, respectively Jing-Jin-Ji(JJJ), Yangtze River Delta region(YRD) and Pearl River Delta region(PRD). It is shown from the 2015-2018 national urban air quality real-time release platform that the surface ozone in JJJ, YRD and PRD has increased each year and reached the highest in 2018. The monthly ozone concentration peaked in June in almost all cities of JJJ, while it had multiple peaks in other two regions (summer and autumn in YRD - and February, May and September in PRD). Simulation with a chemical transport model(GEOS-Chem) indicates that the formation of ozone is affected by the optical properties of PM&lt;sub&gt;2.5&lt;/sub&gt; and also the heterogeneous uptake of N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; on sea salt aerosol.&lt;/p&gt;

scholarly journals Megalopolis unbound: Knowledge collaboration and functional polycentricity within and beyond the Yangtze River Delta Region in China, 2014

Urban Studies ◽  
2016 ◽  
Vol 55 (2) ◽  
pp. 443-460 ◽  
Author(s):  
Yingcheng Li ◽  
Nicholas Phelps
Keyword(s):  
Yangtze River ◽  
Global Scale ◽  
Yangtze River Delta ◽  
River Delta ◽  
World City ◽  
Urban Systems ◽  
Future Research ◽  
Delta Region ◽  
Yangtze River Delta Region ◽  
Knowledge Collaboration

Recent work on world city networks, urban polycentricity and megapolitan urban forms share an interest in the economic functionality of inter-city linkages. The intersection of these bodies of literature is in the often overlooked defining features of megalopolitan forms – their being the ‘hub’ that links national to international urban systems and the ‘incubator’ within national urban systems (Gottmann, 1976). With this intersection in mind, this paper measures the functional polycentricity of China’s Yangtze River Delta Region (YRDR) at different geographical scales from an intercity knowledge collaboration perspective. The paper uses data on co-publications as an indicator of knowledge linkages between cities within and beyond this megalopolis. The YRDR can be seen as functionally polycentric at the megapolitan scale but this functional polycentricity decreases with increases in the geographical scale at which interurban linkages are considered. Furthermore, a multi-scalar analysis of functional polycentricity helps identify the hub role of Shanghai. The results show that Shanghai’s knowledge hub role is currently present at the national scale. It may take some time for Shanghai to become a knowledge hub at the global scale given its not-so-strong international links and relatively weak local links. The paper concludes with some suggestions for future research agendas.

scholarly journals Source, transport and impacts of a heavy dust event in the Yangtze River Delta, China in 2011

2013 ◽  
Vol 13 (8) ◽  
pp. 21507-21540
Author(s):  
X. Fu ◽  
S. X. Wang ◽  
Z. Cheng ◽  
J. Xing ◽  
B. Zhao ◽  
...  
Keyword(s):  
Air Quality ◽  
Yangtze River ◽  
Eastern China ◽  
Yangtze River Delta ◽  
River Delta ◽  
Dust Particles ◽  
The Yangtze River ◽  
Dust Event ◽  
The Yrd ◽  
The Yangtze River Delta

Abstract. During 1 to 6 May 2011, a dust event was observed in the Yangtze River Delta region (YRD). The highest PM10 concentration reached over 1000 μg m−3 and the visibility was below 3 km. In this study, the Community Multi-scale Air Quality modeling system (CMAQ5.0) coupled with an in-line windblown dust model was used to simulate the formation, spatial and temporal characteristics of this dust event, and analyze its impacts on deposition and photochemistry. The threshold friction velocity for loose smooth surface in the dust model was revised based on Chinese data to improve the model performance. The comparison between predictions and observations indicates the revised model can reproduce the transport and pollution of the event. The simulation results show that the dust event was affected by formation and transport of Mongolian cyclone and cold air. Totally about 695 kt dust particles (PM10) were emitted in Xinjiang Province and Mongolia during 28 to 30 April, the dust band swept northern, eastern China and then arrived in the YRD region on 1 May 2011. The transported dust particles increased the mean surface layer concentrations of PM10 in the YRD region by 372% during 1 to 6 May and the impacts weakened from north to south due to the removal of dust particles along the path. Accompanied by high PM concentration, the dry deposition, wet deposition and total deposition of PM10 in the YRD reached 184.7 kt, 172.6 kt and 357.32 kt, respectively. These deposited particles are very harmful because of their impacts on urban environment as well as air quality and human health when resuspending in the atmosphere. Due to the impacts of mineral dust on atmospheric photolysis, the concentrations of O3 and OH were reduced by 1.5% and 3.1% in the whole China, and by 9.4% and 12.1% in the YRD region, respectively. The work of this manuscript is meaningful for understanding the dust emissions in China as well as for the application of CMAQ in Asia. It is also helpful to understand the formation mechanism and impacts of dust pollution in the YRD.

scholarly journals Comparison of Ozone and PM2.5 Concentrations over Urban, Suburban, and Background Sites in China

2020 ◽  
Vol 37 (12) ◽  
pp. 1297-1309
Author(s):  
Lan Gao ◽  
Xu Yue ◽  
Xiaoyan Meng ◽  
Li Du ◽  
Yadong Lei ◽  
...  
Keyword(s):  
Urban Areas ◽  
Surface Ozone ◽  
Fine Particulate Matter ◽  
Eastern China ◽  
Yangtze River Delta ◽  
River Delta ◽  
Monitoring Data ◽  
Quality Data ◽  
Urban Region ◽  
Country Level

AbstractSurface ozone (O3) and fine particulate matter (PM2.5) are dominant air pollutants in China. Concentrations of these pollutants can show significant differences between urban and nonurban areas. However, such contrast has never been explored on the country level. This study investigates the spatiotemporal characteristics of urban-to-suburban and urban-to-background difference for O3 (Δ[O3]) and PM2.5 (Δ[PM2.5]) concentrations in China using monitoring data from 1171 urban, 110 suburban, and 15 background sites built by the China National Environmental Monitoring Center (CNEMC). On the annual mean basis, the urban-to-suburban Δ[O3] is −3.7 ppbv in Beijing-Tianjin-Hebei, 1.0 ppbv in the Yangtze River Delta, −3.5 ppbv in the Pearl River Delta, and −3.8 ppbv in the Sichuan Basin. On the contrary, the urban-to-suburban Δ[PM2.5] is 15.8, −0.3, 3.5 and 2.4 µg m−3 in those areas, respectively. The urban-to-suburban contrast is more significant in winter for both Δ[O3] and Δ[PM2.5]. In eastern China, urban-to-background differences are also moderate during summer, with −5.1 to 6.8 ppbv for Δ[O3] and −0.1 to 22.5 µg m−3 for Δ[PM2.5]. However, such contrasts are much larger in winter, with −22.2 to 5.5 ppbv for Δ[O3] and 3.1 to 82.3 µg m−3 for Δ[PM2.5]. Since the urban region accounts for only 2% of the whole country’s area, the urban-dominant air quality data from the CNEMC network may overestimate winter [PM2.5] but underestimate winter [O3] over the vast domain of China. The study suggests that the CNEMC monitoring data should be used with caution for evaluating chemical models and assessing ecosystem health, which require more data outside urban areas.

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