Impact of Hinterland Manufacturing on the Development of Container Ports: Evidence from the Pearl River Delta, China

Container ports and hinterland manufacturing are two important forces of the local participation in economic globalization.This study,taking the Pearl River Delta(PRD),China with an export-oriented economy as an example,applies Huff and panel regres-sion models to evaluate the impact of hinterland manufacturing on the development of container ports during the period of 1993–2019.The results show that 1)the spatial patterns of hinterlands for hub ports help to determine the distribution range and scale of economic variables that affect port throughput;2)the hinterland’s gross manufacturing output has universally positive influence on port through-put,wherein export-oriented processing and the entire manufacturing industry have significantly positive impact on port throughput in 1993–2011 and 2001–2019,respectively;3)the two internal structural factors related to an export-oriented economy,labor-intensive sectors and foreign-funded terminals,have positively moderate the direct influence of hinterland manufacturing on port throughput.Our results highlight the importance of local context in understanding port-manufacturing relationship in developing economies.Based on our findings,policy implications are further proposed to enhance port network organization in PRD.

Microscopic analysis of saturated soft clay in Pearl River Delta

A series of researches were carried out for the soil samples in the Pearl River Delta under the action of consolidation loads,such as the quantitative analyses of the pore scale,shape and size distributions of micro-structure units,with an environmental scanning electron microscope (ESEM),a mercury intrusion analyzer and a mineral diffractometer. The experimental results show that the consolidation pressures remarkably change the pore sizes and distribution characteristics of the silt,thus changing its compressibility and permeability. This can be proved by the fact that,in the earlier stage with a consolidation pressure of p<200 kPa,the pore sizes are greater and the compressibility and permeability coefficients are larger. However,they rapidly decrease with the increase in consolidation pressure. And in the later stage with a consolidation pressure of p>200 kPa,the pore sizes are smaller and the compressibility and permeability coefficients are less. Therefore,the empirical formulas of compression coefficient and permeability coefficient vs consolidation load and average pore diameter are deduced.

Regional Geochemical Characteristics and Influence Factors of Soil Elements in the Pearl River Delta Economic Zone, China

Soil heavy metal pollution is one of the main environmental problems in Pearl River Delta Economic?Zone of China. Based on multi-purpose regional geochemical survey, regional eco-geochemical assessment, local eco-geochemical assessment and comprehensive appraisal, the eco-geochemical survey and assessment in Pearl River Delta Economic Zone of 41,698 km2?were completed. Samples from soils were collected in accordance with the two-layer grid method. Totally 54 elements and indicators for soils were determined. Compared to deep soils, the sampled surface soils are enriched in OrgC, N, P, Cd, S,Hg, Ag, B, Au, S and poor with As, Ni, I, Co, Cr, V, MgO, Sc, Al2O3, Fe2O3?etc. The characteristics of geochemical reference value of element in soil that inherited soil parent material and regional elements combined features reflected that the elements enriched in the soil was interrelated with acid rock, sandstone and shale. The spatial distribution characteristics of element regional geochemistry were conditional by regional environmental geological conditions,and effected by human activities. The Pearl River Delta plain is a typical geochemical landscape area with regional anomaly of multiple-elements. The north, western and eastern parts of the Pearl River Delta Economic Zone are quite different in geochemical features due to regional geological background, soil parent materials, geomorphic characteristics and human activities. Environment quality evaluation results show that the grade I and grade II soil accounted for 19.9% and 57.3% of the total area. Many samples that widely distributed in the economic developed of Pearl River Delta Plain area reached the third-grade of national soil environment standard. The soil enriched in Cd, Hg, As, and the area ratio accounting for 22.8% of the total area. It is mainly controlled by the geochemical background, the Pearl River Delta formation evolution process, especially the marine transgression process lead to Cd, Cu, Zn and Pb enrichment in Pearl River Delta plain. At the same time, under the influence of higher pressure of human activities, all kinds of exogenous input material carrying heavy metal pollutants on soil environmental quality also could not to ignore.

Empirical Analysis of City Contact in Zhujiang(Pearl) River Delta, China

In traditional urban geography, city contact research is a classic study element in city research. In general, researchers use the traditional gravity model to characterize the contacts that exist between two cities. The traditional gravity model assumes ideal conditions, but these preconditions and their results often do not exist in realistic conditions. Thus, we used a modified gravity model to characterize the city contacts within a specific region. This model considers factors such as intercity complementarities, government intervention, and the diversity of the transportation infrastructure which is characterized as the transportation distance instead of the traditional Euclidean distance. We applied this model to an empirical study of city contact in the Zhujiang(Pearl) River Delta(PRD) of China. The regression results indicated that the modified gravity model could measure city contact more accurately and comprehensively than the traditional gravity model, i.e., it yielded a higher adjusted R2 value(0.379) than the traditional gravity model result(0.259). Our study also suggests that, in addition to urban-regional and metropolitan development, the complementarities of the basic functions of cities at the administrative and market levels, as well as the corporeal and immaterial levels, play very significant roles in the characterization of city contact. Given the complexity of city contact, it will be necessary to consider more relevant influential factors in the modified gravity model to characterize the features of city contact in the future.

The Age of the Old Transgression Sequence in the Pearl River Delta, China

The Pearl River Delta （PRD） is located in the north coast area of the South China Sea （SCS）. As one of the largest delta in China, only the two latest events among the several tens of eustatic fluctuations occurring in the Quaternary were recorded in almost whole area of the PRD.

Projection of the Zhujiang(Pearl) River Delta's potential submerged area due to sea level rise during the 21st century based on CMIP5 simulations

Projections of potential submerged area due to sea level rise are helpful for improving understanding of the influence of ongoing global warming on coastal areas. The Ensemble Empirical Mode Decomposition method is used to adaptively decompose the sea level time series in order to extract the secular trend component. Then the linear relationship between the global mean sea level （GMSL） change and the Zhujiang （Pearl） River Delta （PRD） sea level change is calculated： an increase of 1.0 m in the GMSL corresponds to a 1.3 m （uncertainty interval from 1.25 to 1.46 m） increase in the PRD. Based on this relationship and the GMSL rise projected by the Coupled Model Intercomparison Project Phase 5 under three greenhouse gas emission scenarios （representative concentration pathways, or RCPs, from low to high emission scenarios RCP2.6, RCP4.5, and RCP8.5）, the PRD sea level is calculated and projected for the period 2006-2100. By around the year 2050, the PRD sea level will rise 0.29 （0.21 to 0.40） m under RCP2.6, 0.31 （0.22 to 0.42） m under RCP4.5, and 0.34 （0.25 to 0.46） m under RCP8.5, respectively. By 2100, it will rise 0.59 （0.36 to 0.88） m, 0.71 （0.47 to 1.02） m, and 1.0 （0.68 to 1.41） m, respectively. In addition, considering the extreme value of relative sea level due to land subsidence （i.e., 0.20 m） and that obtained from intermonthly variability （i.e., 0.33 m）, the PRD sea level will rise 1.94 m by the year 2100 under the RCP8.5 scenario with the upper uncertainty level （i.e., 1.41 m）. Accordingly, the potential submerged area is 8.57x103 km2 for the PRD, about 1.3 times its present area.

Peripheral Challenge in Container Port System:A Case Study of Pearl River Delta

The growth of peripheral ports to dominant hubs has been well documented in North America and Europe,and has led to the elaboration of several theoretical models.However,although changes in containerization growth have been taking place in the South and East Asia in recent years,particularly in China,only a few studies have fo-cused on this region.The Pearl(Zhujiang) River Delta(PRD) has a typical port system with hub and peripheral ports,and provides an excellent case for studying the Peripheral Challenge.This paper introduces the theoretical evidence of the Hayuth model and analyzes the evolution of the container port system in the PRD with five phases:1) phase I:preconditions for change and phase II:initial container port development in the 1970s and early 1980s;2) phase III:diffusion,consolidation,and port concentration in the middle and late 1980s;3) phase IV:the load center in the 1990s;and(4) phase V:the Peripheral Challenge since the late 1990s.The results illustrate that the Shenzhen port presents mounting challenges to the Hong Kong port,descending from a transshipment hub of China to a regional load center of Southeast China.Furthermore,this paper explores five points that have led to the evolution of the port system in the PRD:1) competition in the regional port systems;2) different interested parties;3) shift of investment strategies of in-ternational terminal operators;4) integration of shipping networks and reorganization of carriers;and 5) cost-based competition.

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.

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.

Space view of the decadal variation for typical air pollutants in the Pearl River Delta （PRD） region in China

The Pearl River Delta （PRD） is one of the most industrialized, urbanized and populated regions in China, and thus has been long suffering from severe air pollutions. Space data provide a unique perspective for investigating the atmospheric environment at a regional scale. By utilizing multiple satellite retrievals from 2005 to 2013, this study presented, for the first time, the spatial patterns and temporal trends of typical air pollutants over PRD and its vicinity. As viewed from space, aerosol optical depth （AOD）, NO2 and SO2 all had their higher values at the central part of PRD, and showed clear descending gradients as moving to the outskirt of this region. As to the inter-annual variation, all these pollutants had decreasing trends in PRD during the study period, which generally agreed with the relevant in situ measurements. However, the satellite retrievals differed from ground measurements when addressing NO2 and SO2 in the vicinity of PRD. This work also provides the inter-comparison among PRD and three other metropolitan clusters in China： PRD had relatively high AOD, moderate NO2 and low SO2 levels, and it was the only region achieving the effective reduction of NO2 and SO2 during last decade. Unlike the previous three pollutants, HCHO observed by satellite showed very special patterns： it had a relatively homogeneous spatial distribution over both of PRD and its vicinity, and presented an opposite increasing trend from 2005 to 2010. Moreover, PRD had the highest HCHO level among all the metropolitan clusters, hinting a considerable contribution of biogenic origins of HCHO in PRD.

Ambient volatile organic compounds at a receptor site in the Pearl River Delta region:Variations,source apportionment and effects on ozone formation

We present the continuously measurements of volatile organic compounds(VOCs)at a receptor site(Wan Qing Sha,WQS)in the Pearl River Delta(PRD)region from September to November of 2017.The average mixing ratios of total VOCs(TVOCs)was 36.3±27.9 ppbv with the dominant contribution from alkanes(55.5%),followed by aromatics(33.3%).The diurnal variation of TVOCs showed a strong photochemical consumption during daytime,resulting in the formation of ozone(O_(3)).Five VOC sources were resolved by the positive matrix factorization(PMF)model,including solvent usage(28.6%),liquid petroleum gas(LPG)usage(24.4%),vehicle exhaust(21.0%),industrial emissions(13.2%)and gasoline evaporation(12.9%).The regional transport air masses from the upwind cities of south China can result in the elevated concentrations of TVOCs.Low ratios of TVOCs/NO_(x)(1.53±0.88)suggested that the O_(3) formation regime at WQS site was VOC-limited,which also confirmed by a photochemical box model with the master chemical mechanism(PBM-MCM).Furthermore,the observation on high-O_(3) episode days revealed that frequent O_(3) outbreaks at WQS were mainly caused by the regional transport of anthropogenic VOCs especially for aromatics and the subsequent photochemical reactions.This study provides valuable information for policymakers to propose the effective control strategies on photochemical pollution in a regional perspective.

Source attribution for mercury deposition with an updated atmospheric mercury emission inventory in the Pearl River Delta Region, China

We used CMAQ-Hg to simulate mercury pollution and identify main sources in the Pearl River Delta (PR.D) with updated local emission inventory and latest regional and global emissions. The total anthropogenic mercury emissions in the PRD for 2014 were 11,939.6 kg. Power plants and industrial boilers were dominant sectors, responsible for 29.4 and 22.7%. We first compared model predictions and observations and the results showed a good performance. Then five scenarios with power plants (PP), municipal solid waste incineration (MSWI), industrial point sources (IP), natural sources (NAT), and boundary conditions (BCs) zeroed out separately were simulated and compared with the base case. BCs was responsible for over 30% of annual average mercury concentration and total deposition while NAT contributed around 15%. Among the anthropogenic sources, IP (22.9%) was dominant with a contribution over 20.0% and PP (18.9%) and MSWI (11.2%) ranked second and third. Results also showed that power plants were the most important emission sources in the central PRD, where the ultra-low emission for thermal power units need to be strengthened. In the northern and western PRD, cement and metal productions were priorities for mercury control. The fast growth of municipal solid waste incineration were also a key factor in the core areas. In addition, a coordinated regional mercury emission control was important for effectively controlling pollution. In the future, mercury emissions will decrease as control measures are strengthened, more attention should be paid to mercury deposition around the large point sources as high levels of pollution are observed.

Photochemical indicators of ozone sensitivity： application in the Pearl River Delta, China

Surface 03 production has a highly nonlinear relationship with its precursors. The spatial and temporal heterogeneity of O3-NOx-VOC-sensitivity regimes complicates the control- decision making. In this paper, the indicator method was used to establish the relationship between 03 sensitivity and assessment indicators. Six popular ratios indicating ozone-precursor sensitivity, HCHO/NOy, H2O2/ HNO3, O3/NOy, O3/NOz, O3/HNO3, and H2O2/NOz, were evaluated based on the distribution of NOx- and VOC-sensitive regimes. WRF-Chem was used to study a serious ozone episode in fall over the Pearl River Delta （PRD）. It was found that the south-west of the PRD is characterized by a VOCsensitive regime, while its north-east is NO y-sensitive, with a sharp transition area between the two regimes. All indicators produced good representations of the elevated ozone hours in the episode on 6 November 2009, with H202/HNO3 being the best indicator. The threshold sensitivity levels for HCHO/NOy, H2O2/HNO3, O3/NOy, O3/NOz, O3/HNO3, and H2O2/NOz were estimated to be 0.41, 0.55, 10.2, 14.0, 19.1, and 0.38, respectively. Threshold intervals for the indicators H2O2/HNO3, O3/ NOy, O3/NOz, O3/HNO3, and H202/NOz were able to identify more than 95% of VOC- and NOx-sensitive grids. The ozone episode on 16 November 16 2008 was used to independently verify the results, and it was found that only H2O2/HNO3 and H2O2/NOz were able to differentiate the ozone sensitivity regime well. Hence, these two ratios are suggested as the most appropriate indicators for identifying fall ozone sensitivity in the PRD. Since the species used for indicators have seasonal variation, the utility of those indicators for other seasons should be investigated in the future work.

Spatial variations of river water quality in Pearl River Delta, China

In Pearl River Delta （PRD）, river water quality has deteriorated gradually due to population increase and ongoing industrialization and urbanization. In this study, multivariate statistic methods were used to assess water quality spatial pattern and to identify characteristics of water quality variation in the PRD. Water quality monitoring of the PRD during the year 2005 and 2008 was conducted at 25 different stations. Seventeen water quality parameters were analyzed for further studying. Results of one-way analysis of variance （ANOVA） indicated that all the parameters except air temperature, water temperature and zinc showed significant difference among monitoring stations in both dry and wet season. Monitoring stations in the PRD were separately classified into three statistically significant clusters at （Olink/Omax） （ 2 in dry and wet season, respectively. The three clusters indicated the similarity and dissimilarity of river water quality among 25 monitoring stations, corresponding to heavy pollution, moderate pollution and slight pollution. Thus, the results of this study are useful to evaluate water quality and manage water resources in the PRD.

珠江三角洲铊在水稻籽实-根系土间迁移及人体健康风险评价

铊(Tl)是一种典型的剧毒重金属元素,其环境行为及人体健康效应日益得到广泛关注,土壤Tl富集会对土壤环境、农作物生长及人体健康造成严重的危害性。珠江三角洲作为土壤重金属富集的典型区域,当前研究主要聚集于Cu、Cd、Pb和As等元素,而对土壤Tl的地球化学特征及其影响因素、生物富集能力及人体健康效应评价的研究较少。本文以珠江三角洲3种成土母质分布区的243套水稻籽实及其根系土样品为研究对象,揭示了水稻根系土Tl含量、生物富集特征及其影响因素,并采用美国环保署(US EPA)推荐的人体健康风险评价模型对研究区土壤Tl的人体非致癌健康风险进行评价。结果表明:水稻根系土Tl含量显著高于我国和广东省土壤Tl含量背景值,18.1%的水稻根系土Tl含量超过加拿大Tl环境质量标准值及瑞士农业土壤Tl标准值(1×10^(-6))。酸性岩浆岩与第四纪沉积物分布区水稻根系土Tl超标率明显高于陆源碎屑岩。水稻根系土Tl含量表现出与K_(2)O、Al_(2)O_(3)、Pb和Zn含量显著相关。综合分析认为珠江流域硫化物矿床风化剥蚀及开采活动是导致下游平原区土壤Tl等重金属元素富集的主要原因。全区20件水稻籽实Tl含量的平均值为0.35×10^(-3),均远低于德国食品安全规定的Tl可食用标准值,水稻籽实Tl生物富集系数主要与根系土Na_(2)O、Zn和Pb含量显著相关。每个样点的HQ值分级结果显示,研究区68%的儿童有中等健康风险,46%的成人有中等健康风险,儿童健康风险显著高于成人。

基于KZ滤波分析气象对珠三角臭氧趋势的影响

基于2015~2021年珠三角臭氧(O_(3))监测数据以及再分析的气象资料,利用Kolmogorov-Zurbenko(KZ)滤波和逐步多元线性回归方法分析O_(3)长期趋势和气象因素之间的关系,量化气象和非气象对珠三角O_(3)日最大8h平均浓度(MDA8O_(3))长期趋势的贡献.结果表明:2015~2021年珠三角MDA8O_(3)增长明显,夏季和秋季O_(3)污染尤为严重.KZ滤波分离出的MDA8O_(3)短期、季节和长期3个分量分别占原始序列方差的60.84%、24.96%和4.33%,各分量之间相互独立,3个分量均与太阳辐射、温度和边界层高度呈正相关,与云量、相对湿度、风速和850hPa经向风呈负相关.此外,气象和非气象影响能分别解释大约64.3%(2.77μg/(m^(3)·a))和35.7%(1.53μg/(m^(3)·a))的MDA8O_(3)长期趋势的增长率(4.29μg/(m^(3)·a)).

乡村都市化:理论思考与珠三角的实践

文章在乡村都市化这一概念的基础上,对乡村都市化相关的理论进行了思考。并结合历史上与国内外的乡村发展历程,提出乡村都市化是中国乡村发展的必要路径。这主要是基于中国在发展过程中所呈现出的两个问题:一是过密化、市场网络断裂和人口迁移的限制;二是工业化与城市化发展不同步。文章以珠三角为案例,探讨了珠三角地区自改革开放以来,在乡村都市化过程中的不同阶段,并为珠三角地区乡村都市化再研究提出了问题与方向。乡村都市化研究需要与乡村振兴以及中国式现代化相结合,才能在未来进行更有针对性的相关学术研究。

某地块土壤污染状况调查中砷超标的原因分析

本文以珠三角某工业地块为研究对象,通过对地块土壤污染状况进行调查,评价该地块的土壤环境质量,并分析历史活动以及周边企业对地块内土壤环境质量的影响。调查结果表明,监测地块的部分土壤样品中重金属砷超过《土壤环境质量建设用地土壤污染风险管控标准(试行)》(GB36600-2018)规定的筛选值,超筛选值土壤样品均位于风化层。经过分析,地块土壤中砷含量高是受到地带性土壤地质背景特征影响造成,非人为因素影响。该地块不属于工业企业生产造成污染的地块,但可能威胁人体健康,在利用开发前应对项目地块开展详细调查和风险评估,进一步确定砷超筛选值区域范围,明确其对人体健康的影响。

珠江三角洲秋季典型光化学污染过程中的臭氧来源分析

利用区域空气质量模型CAMx模拟珠江三角洲地区（简称珠三角）2009年11月臭氧浓度演变过程,运用臭氧源识别技术（OSAT）对其中两个典型的光化学污染日进行臭氧来源识别,并与清洁日的情况做对照分析。结果表明,广州市区和东莞的排放对本地及珠三角西南部臭氧贡献很大（15-30μL/m3）,深圳宝安区排放对珠江口有明显的贡献（15-25μL/m3）。流动源和溶剂使用源是珠三角臭氧生成最主要的两类前体物排放源,主要影响范围覆盖珠三角的中部和西部,流动源对佛山和江门交界地区的臭氧小时浓度贡献可达50μL/m3。较高的边界外传输使得珠三角在出现不利污染气象条件的情况下更易发生臭氧污染,但珠三角的前体物排放是造成污染时段臭氧浓度升高的主要原因,控制珠三角内的污染源排放对控制臭氧污染具有关键作用。

珠江三角洲城市群PM_(10)的相互影响研究

利用Models-3/CMAQ模拟系统,对珠江三角洲地区2006年10月的大气PM10污染进行模拟研究。通过敏感性分析,获得各城市PM10浓度随不同污染源削减的变化情况,量化出城市间空气污染的相互影响。结果显示,珠江三角洲地区已形成PM10区域性污染的格局,广州、佛山、江门、东莞等地是珠三角地区PM10的重要源贡献区域。提出相对敏感系数作为表征外来源影响程度的指标,珠海、江门、中山、佛山等地的PM10浓度受到外来源的显著影响,城市间输送已成为造成珠三角地区PM10污染的重要因素。对重点城市源的合理削减和有效控制,以及城市群的统一规划、相互协作、联防联控是改善珠三角地区空气质量的唯一途径。