Spatially Heterogeneous Response of Carbon Storage to Land Use Changes in Pearl River Delta Urban Agglomeration, China

Carbon storage of terrestrial ecosystems plays a vital role in advancing carbon neutrality. Better understanding of how land use changes affect carbon storage in urban agglomeration will provide valuable guidance for policymakers in developing effective regional conservation policies. Taking the Pearl River Delta Urban Agglomeration(PRDUA) in China as an example, we examined the heterogeneous response of carbon storage to land use changes in 1990–2018 from a combined view of administrative units and physical entities. The results indicate that the primary change in land use was due to the expansion of construction land(5897.16 km2). The carbon storage in PRDUA decreased from 767.34 Tg C in 1990 to 725.42 Tg C in 2018 with a spatial pattern of high wings and the low middle. The carbon storage loss was largely attributed to construction land expansion(55.74%), followed by forest degradation(54.81%). Changes in carbon storage showed significant divergences in different sized cities and hierarchical boundaries. The coefficients of geographically weighted regression(GWR) reveal that the alteration in carbon storage in Guangzhou City was more responsive to changes in construction land(-0.11) compared to other cities, while that in Shenzhen was mainly affected by the dynamics of forest land(8.32). The change in carbon storage was primarily influenced by the conversion of farmland within urban extent(5.05) and the degradation of forest land in rural areas(5.82). Carbon storage changes were less sensitive to the expansion of construction land in the urban center, urban built-up area, and ex-urban built-up area, with the corresponding GWR coefficients of 0.19, 0.04, and 0.02. This study necessitates the differentiated protection strategies of carbon storage in urban agglomerations.

Impacts of Weather Conditions Modified by Urban Expansion on Surface Ozone: Comparison between the Pearl River Delta and Yangtze River Delta Regions

In this paper, the online weather research and forecasting and chemistry （WRF-Chem） model is used to explore the impacts of urban expansion on regional weather conditions and its implication on surface ozone concentrations over the Pearl River Delta（PRD） and Yangtze River Delta（YRD） regions. Two scenarios of urban maps are used in the WRF-Chem to represent the early 1990s （pre-urbanization） and the current urban distribution in the PRD and the YRD. Month-long simulation results using the above land-use scenarios for March 2001 show that urbanization increases both the day- and night-time 2-m temperatures by about 0.6℃and 1.4℃, respectively. Daytime reduction in the wind speed by about 3.0 m s-1 is larger than that for the nighttime （0.5 to 2 m s-1）. The daytime increase in the PBL height （〉 200 m） is also larger than the nighttime （50-100 m）. The meteorological conditions modified by urbanization lead to detectable ozone-concentration changes in the PRD and the YRD. Urbanization increases the nighttime surface-ozone concentrations by about 4.7%-8.5% and by about 2.9%-4.2% for the daytime. In addition to modifying individual meteorological variables, urbanization also enhances the convergence zones, especially in the PRD. More importantly, urbanization has different effects on the surface ozone for the PRD and the YRD, presumably due to their urbanization characteristics and geographical locations. Even though the PRD has a smaller increase in the surface temperature than the YRD, it has （a） weaker surface wind speed, （b） smaller increase in PBL heights, and （c） stronger convergence zones. The latter three factors outweighed the temperature increase and resulted in a larger ozone enhancement in the PRD than the YRD.

Urbanization effect on precipitation over the Pearl River Delta based on CMORPH data

Based on the satellite data from the Climate Prediction Center morphing(CMORPH) at very high spatial and temporal resolution, the effects of urbanization on precipitation were assessed over the Pearl River Delta(PRD) metropolitan regions of China. CMORPH data well estimates the precipitation features over the PRD. Compared to the surrounding rural areas, the PRD urban areas experience fewer and shorter precipitation events with a lower precipitation frequency(ratio of rainy hours, about 3 days per year less); however, short-duration heavy rain events play a more significant role over the PRD urban areas. Afternoon precipitation is much more pronounced over the PRD urban areas than the surrounding rural areas, which is probably because of the increase in short-duration heavy rain over urban areas.

Tows Matrix Analysis on Developing Urban Agriculture in the Pearl River Delta Area

Based on the introduction of the profile of Pearl River Delta area, the strengths, weaknesses, opportunities and threats of developing urban agricultural in Pearl River Delta area are analyzed by using the SWOT analysis. The strengths are analyzed from three aspects, covering natural resources, geographic advantages and technological advantages; the weaknesses are analyzed from the terms of land resources, labor cost, industrial scale and quality of personnel involved; opportunities are analyzed from the aspects of potential clients, favorable policies and markets; the threats are analyzed from two aspects, including concept factor and income gap between urban and rural areas. on the basis of the above analyses, the countermeasures and suggestions on the development of urban agriculture in the Pearl River Delta area are put forward.

Evolution of Living Space in Traditional Villages in the Pearl River Delta under the Influence of Urbanization:A Case Study of Xiaozhou Village in Guangzhou City

Traditional villages in the Pearl River Delta are known as "Lingnan water village".Urbanization affects the style of traditional villages in three ways.It also presents a positive side under the background of new urbanization.The living space of Xiaozhou Village has the unique characteristics of Lingnan water village.At the same time,it is obviously affected by urbanization.Industrialization and commercialization continue to promote the villagers to dismantle the old and build new ones until it becomes a village in the city.The evolution of the traditional living space is reflected in three aspects:being nibbled away or even disappeared,destroying the traditional style,function disappearance or transformation.In the later stage of urbanization,some living spaces have been repaired and updated.

Analysis on Ecological Footprint of the Urban Agglomeration in Pearl River Delta

[Objective] The research aimed to calculate and analyze ecological footprint of the urban agglomeration in Pearl River Delta in 2009. [Method] 9 cities in Pearl River Delta as research zone, by using calculation model of the ecological footprint, ecological footprint and security of the urban agglomeration in Pearl River Delta were calculated. Current situation and sustainable development condition of the ecological environment in Pearl River Delta were conducted quantitative analysis. [Result] Except construction land and woodland, other 4 kinds of lands were all in ecological deficit states in Pearl River Delta. Especially arable land and fossil fuel land had obvious ecological deficit. [Conclusion] Biological resource consumption level and energy consumption level in Pearl River Delta were higher. We ought to take a variety of measures to reduce ecological deficit, making development manner turn toward sustainable direction.

KNOWLEDGE DISCOVERY OF REMOTELY SENSED DATA FROM ECOLOGICAL VIEW——A Case Study of Urban Spatial-temporal Relationship in the Pearl River Delta

From the ecological viewpoint this paper discusses the urban spatial-temporal relationship. We take regional towns and cities as a complex man-land system of urban eco-community. This complex man-land system comprises two elements of ' man' and ' land' . Here, ' man' means organization with self-determined consciousness, and ' land' means the physical environment (niche) that ' man' depends on. The complex man-land system has three basic components. They are individual, population and community. Therefore there are six types of spatial relationship for the complex man-land system. They are individual, population,community,man-man, land-land and man-land spatial relationships. Taking the Pearl(Zhujiang) River Delta as a case study, the authors found some evidence of the urban spatial relationship from the remote sensing data. Firstly, the concentration and diffusion of the cities spatial relationship was found in the remote sensing imagery. Most of the cities concentrate in the core area of the Pearl River Delta, but the diffusion situation is also significant. Secondly, the growth behavior and succession behavior of the urban spatial relationship was found in the remote sensing images comparison with different temporal data. Thirdly, the inheritance, break, or meeting emergency behavior was observed from the remote sensing data. Fourthly, the authors found many cases of symbiosis and competition in the remote sensing data of the Pearl River Delta. Fifthly, the autoeciousness, stranglehold and invasion behavior of the urban spatial relationship was discovered from the remote sensing data.

Influence of International Trade on the Urbanization in the Pearl River Delta

The Pearl River Delta is a typical representative of China s coastal economic belt and one of the most active regions for international trade.It has important reference value for the urbanization of other coastal economic regions in China to study the impact of international trade on the urbanization of the Pearl River Delta.This paper constructs the theoretical model of the three factors of export trade,import trade and industrial scale affecting the urbanization of the Pearl River Delta.It is empirically found that the international trade has positive effects on the total effect of urbanization in which export trade and import intermediate product trade have a positive effect on urbanization,and import trade and export intermediate product trade have a negative effect on urbanization.

An Overall Urban System: Integrating Central Place Theory and Urban Network Idea in the Greater Pearl River Delta of China

Following a half century of popularity, central place theory experienced 20 years of neglect when the new urban system theory of network modeling gained attention at the beginning of the 1990s. However, central place theory remains valid, and it seems there has been a reemergence with it. Using the Greater Pearl River Delta (Greater PRD) as an experimental study region, this paper intends to present an empirical study that validates central place theory and shows that it can be integrated into an overall regional urban system. The study uses the compound Central Place Importance (CPI) to evaluate whether there is a hierarchy among the urban centers within the study area. The results indicate the existence of a hierarchy. Furthermore, empirical observation finds distinct complementarity relationships, rank-size distributions, and co-operative actions between the different cities, thus substantiating the claim that central place theory can be incorporated into an overall regional urban system. Besides, the presence of the densely distributed modern infrastructure system also appears to constitute a dimension of the overall urban system. There need further theoretical and empirical studies in order to support this proposition.

SWOT Analysis of Urban Greening Maintenance and Management in the Central Pearl River Delta

We take Shunde District,Foshan City in Guangdong Province for example,to carry out SWOT analysis of urban greening maintenance and management.The strengths of greening management and maintenance in Shunde District are as follows:(i)The greening area and quality are continuously improved in the downtown of Shunde District;(ii)The management and maintenance work is carried out well;(iii)The management and maintenance level tends to be increasingly perfected.The weaknesses of greening management and maintenance are as follows:(i)The fees for greening management and maintenance are very low;(ii)There is corner as yet untouched in the junction of some town streets;(iii)The greening management and maintenance technicians are unprofessional;(iv)The greening management is not in place;(v)There is management vacancy phenomenon in the management and maintenance of regional green space;(vi)The design and construction phase is flawed.Finally,based on the analysis of strengths and weaknesses of greening,we put forth the recommendations for the development of management and maintenance in urban green space.

Industrial carbon emissions and influencing factors in the Yangtze River Delta urban agglomeration

This paper calculates the industrial carbon emissions of the Yangtze River Delta urban agglomeration over the period 2006-2013. An empirical analysis is conducted to find out the influencing factors of industrial carbon emissions of the Yangtze River Delta urban agglomeration, using a spatial Durbin panel model. The results show that cities with larger industrial carbon emissions often enjoy low annual growth rates, while the cities with smaller ones enjoy higher annual growth rate; There exists a comparatively strong positive correlation in space in per capita carbon emission; urbanization, and total population. GDP per capita and international trade are the main influencing factors of industrial carbon emissions; There are spatial spillover effects on international trade and urbanization of neighboring cities, which have a significant impact on local industrial carbon emissions.

The Effect of Urban Agglomeration Expansion on PM_(2.5) Concentrations: Evidence from a Quasi-natural Experiment

This study constructs a quasi-natural experiment based on the expansion of the Yangtze River Delta urban agglomeration(YRDUA) of China in 2010 to investigate the impact and inner mechanism of urban agglomeration expansion on fine particulate matter(PM_(2.5)) concentrations through propensity scores in difference-in-differences models(PSM-DID) using panel data from 286 prefecturelevel cities in China from 2003 to 2016. The results show that 1) urban agglomeration expansion contributes to an overall decrease in PM_(2.5)concentration, which is mainly achieved from the original cities. For the new cities, on the other hand, the expansion significantly increases the local PM_(2.5)concentration. 2) In the long term, the significant influence of urban agglomeration expansion on PM_(2.5)concentration lasts for three years and gradually decreases. A series of robustness tests confirm the applicability of the PSM-DID model.3) Cities with weaker government regulation, a better educated population and higher per capita income present stronger PM_(2.5)reduction effects. 4) Urban agglomeration expansion affects the PM_(2.5)concentration mainly through industrial transfer and population migration, which cause a decrease in the PM_(2.5)concentration in the original cities and an increase in the PM_(2.5)concentration in the new cities.Corresponding policy suggestions are proposed based on the conclusions.

Measurement of Digital Economy Development Level in Yangtze River Delta and Its Influence on Ecological Efficiency

Based on the panel data of 41 cities in the Yangtze River Delta from 2007 to 2018,this paper empirically tests the impact of digital economy development on urban ecological efficiency in the Yangtze River Delta.The results show that the development level of digital economy in Yangtze River Delta urban agglomeration is fluctuating and rising;the development of digital economy has a significant positive role in promoting the improvement of urban ecological efficiency;there is significant regional heterogeneity in the promotion of ecological efficiency by digital economy,especially in central cities.

Relationship Between Producer Services Developing Level and Urban Hierarchy——A Case Study of Zhujiang River Delta

As the Central Place Theory indicates, the centricity of a central city can influence the extension of its ser- vice. Since the service industry in the theory is mostly consumer services, it is worth studying the relationship between the producer services and the centricity of the city in the service society with producer services becoming a more im- portant part of the service industry. The paper takes the case of the Zhujiang (Pearl) River Delta (PRD), a developed region in China, to study the relationship between the developing level of producer services and the urban hierarchy. Based on the analysis about the spatial difference of the producer services in the nine cities of the PRD, and the divi- sion of the nine cities according to some economic indices, it is shown that there is a correlation between the develop- ing level of producer services and the urban hierarchy. Furthermore, two deductions about the future status of the pro- ducer services in the city and the location of the producer services in a large region can be made from this correlation between the developing level of producer services and the urban hierarchy.

Effects of Land Use Changes Across Different Urbanization Periods on Summer Rainfall in the Pearl River Delta Core Area

The Pearl River Delta(PRD)is one of the three urban agglomerations in China that have experienced rapid development.For this study,a core area of the PRD was identified,comprising the highly urbanized areas of Guangzhou,Foshan,Zhongshan,Zhuhai,Shenzhen,and Dongguan Cities.The expansion of these urban areas was tracked across three time periods—the year population urbanization rate exceeded 70%(2000),18 years before(1982),and 18 years after(2018).This study used the Weather Research and Forecasting(WRF)model to explore summer rainfall changes across different urbanization periods in the PRD core area.The results show that urban land expansion mainly occurred in the post urbanization period.Rainfall changes acros s different urbanization periods were roughly consistent with previously observed spatial and temporal changes accompanying urban expansion in the PRD core area.Extreme rainfall mainly increased in the post urbanization period,shifting rainstorm center towards the PRD core area.Further causal analysis revealed that land use changes affected rainfall by altering thermodynamics and water vapor transfer.The urban expansion changed the surface energy balance,resulting in increased surface heating and heat island effects.The heat island effects thickened the planetary boundary layer and increased vertical wind speeds,which initiated dry island effects,thereby causing more water vapor transportation to the atmosphere.Consequently,rainstorms and extreme rainfall events have become concentrated in urban areas.

Spatial Structure and Land Use Control in Extended Metropolitan Region of Zhujiang River Delta,China

The Zhujiang (Pearl) River Delta is one of the most developed Extended Metropolitan Regions (EMR) in China.With the rapid urbanization,the agglomeration of population and industries has emerged,which has led to dramatic changes of spatial structure and land use in this region.With data of high resolution TM remote sensing images and Google Earth maps,this paper identified and analyzed the spatial pattern of the Zhujiang River Delta EMR using Envy and ArcGIS tools.It was found that 1) the industrial land uses were expanding substantially,particularly on the bank sides of the Zhujiang River estuary;2) large-scale housing developments were concentrated in the fringe of metropolitan areas such as those of Guangzhou and Shenzhen;3) a regional transportation network with the spatial pattern of ″1 circle +2 pieces + 3 axes″ had significantly affected the location choice of manufacture enterprises.At the same time,both highly specialized land use and severely mixed land use patterns were identified.As a consequence of the latter,land use efficiency of the whole EMR areas was reduced.Moreover,ecologic and environmental problems were severe.Based on the above analysis,suggestions were given from the viewpoint of spatial safety,land use efficiency,and the reorganization of spatial structure in the Zhujiang River Delta EMR.

SPATIO-TEMPORAL CHARACTERISTICS OF NO2 IN PRD URBAN GROUP AND THE ANTHROPOGENIC INFLUENCES ANALYSIS BASED ON OMI REMOTE SENSING DATA

Spatio-temporal distribution characteristics and variation trends of tropospheric NO_2 in Pearl River Delta(PRD) urban group and its adjacent areas were analyze from 2005 to 2013 based on remote sensing data from ozone monitoring instrument(OMI) satellite, and further explored the impact of human activities on NO_2. Compared with the ground observation data, the OMI NO_2 remote sensing data displayed high reliability. Due to active industrial production, high car ownership, great energy and power consumption, the average tropospheric NO_2concentration(7.4×1015molec/cm2) of PRD region is about 3 times of the adjacent areas. At the same time, the regional high pollution NO_2 in PRD region as a whole, the urban group effect is remarkable. Sinusoidal model can well fit the periodic variation of the NO_2 in PRD and adjacent areas. NO_2 concentration was highest in winter while lowest in summer. The concentration of NO_2 in PRD region is decreasing in recent 9 years, which has a significantly negative correlation with the second industry output and car ownership. This suggests that the nitrogen oxide emissions governance in PRD region had achieved initial results. The concentration of NO_2 increased significantly in the eastern and northern Guangdong Province, there are good positive correlations with the second industrial outputs and car ownerships, it is thus clear that industrial emissions and automobile exhausts are important sources of NO_2 in these regions. The concentration of NO_2 in western Guangdong area is stable.

Materializing the “Urban Region” Concept by Integrating Ecological Networks and Central Place Theory

This paper attempts to integrate urban development and ecological conservation by applying and syncretizing the “urban region” concept from landscape ecology and the “city-region” concept from socioeconomics. First, various concepts pertaining to regions are discussed and then, the integration of ecological conservation and urban development on a regional scale is introduced. Subsequently, the Greater Pearl River Delta, in China, is used as a case study area and landscape ecology’s “urban region” concept is applied to produce a landscape spatial arrangement framework for an urban region. This framework is achieved through the following steps: conceiving the study area as a region that consists of two urban regions, arranging ecological conservation landscapes by establishing a regional ecological network within the urban-region rings;and formulating an urban development strategy using central place theory. The resulting landscape spatial arrangement solution includes natural protection areas that cover half of the study area, several key strategic urbanizing locations, and suggestions for the strict protection of certain agricultural land-use areas. We believe that this framework facilitates a feasible exploration of land-use planning on a regional scale, although more in-depth studies are required to refine this approach.

京津冀与珠三角协同创新比较分析

围绕着以“研发—中介—应用”为核心群落的创新生态系统,依次构建了京津冀和珠三角城市群协同创新网络,比较分析了京津冀和珠三角城市群在协同创新方面的特征与差异,结果显示:除中介群落外,京津冀创新群落并不具有规模优势;京津冀和珠三角均呈现创新核心城市和腹地城市的地位差距明显缩小、创新关联程度明显加强、腹地城市创新外向活跃度明显上升的趋势;但珠三角协同创新水平领先于京津冀。通过与珠三角的对比,总结了京津冀协同创新中存在的短板与问题,并从创新人才管理体制创新、推行新型科研模式、培育科技成果转化公共服务平台、构建承载先进制造业集群的园区共同体、探索建设产业创新合作“双向飞地”等方面提出了政策建议。

长三角城市群FDI、技术创新与先进制造业集群发展

FDI和技术创新是长三角城市群先进制造业集群发展的重要影响因素。文章基于2010—2021年长三角城市群26个城市面板数据,分析FDI对先进制造业集群发展的直接作用机制以及技术创新在FDI与先进制造业集群发展之间的中介作用机制,并运用面板回归模型和中介效应模型检验理论假设。研究结果表明:长三角城市群FDI对先进制造业集群发展具有显著的正向作用,其作用机制主要表现为促进集群网络化、产业链优化和劳动力流动;技术创新在FDI与先进制造业集群发展之间具有显著的中介作用。根据研究结论提出长三角城市群促进FDI高质量发展、提高先进制造业集群的科技创新能力、加强FDI与技术创新的协同效应等政策建议。