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.

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.

Leave or Stay?Antecedents of High-level Talent Migration in the Pearl River Delta Megalopolis of China:from a Perspective of Regional Differentials in Housing Prices

Rapid urbanization and population growth have triggered an increase in urban housing demand and rising housing prices,which can influence the migration intention of high-level talents.Much work within the literature has focused more on the migration of the general public.However,antecedents of migration intention and the impact of housing prices on the migration of high-level talents remain unclear.Therefore,based on the push-pull theory,this study investigates the influencing factors of talent migration intention and explores the role of housing prices.This study reveals a complex mechanism underlying migration decisions by using logistic regression models and survey data of high-level talents in the Pearl River Delta(PRD)megalopolis of China.The results indicate that:1)in high house-price regions,social integration is the primary push factor,and the main factors for retaining talents are the expectation of future work and intimate family relationships;2)in medium house-price regions,the main factors that attract talents are the current salary level and close family ties;3)in low house-price regions,living convenience is a determining factor in retaining talents.This study provides a new perspective for talent mobility research and offers valuable inputs for retaining and attracting talents in different economic development regions.Findings are of great significance for formulating talent introduction policies and forming a new pattern of rational spatial docking and effective allocation of human resources.

Forest Evapotranspiration in Pearl River Delta based on Remote Sensing Technology

Evapotranspiration ratio of six major forest types in the Pearl River Delta was studied in this paper, and the six forest types included eucalyptus forest, fruit forest, coniferous forest, shrub forest, coniferous forest, and broad-leaved mixed for- est. The mechanism of PT-T model was analyzed based on Priestley-Taylor ex- tended model, and the result showed that land surface temperature or temperature difference between day and night could be used to evaluate the evapotranspiration factor. The evapotranspiration of 6 forest types was estimated with MODIS data and TM data and weather information during 2008-2009. The result suggested that water consumption of different forest differs insignificantly, and the EF of eucalyptus is not high.

Characterizing ionic species in PM_(2.5) and PM_(10) in four Pearl River Delta cities,South China

PM2.5 and PM10 samples were collected at four major cities in the Pearl River Delta （PRD）, South China, during winter and summer in 2002. Six water-soluble ions, Na^＋, NH4＋, K^＋, Cl^-, NO3^- and SO4^2- were measured using ion chromatography. On average, ionic species accounted for 53.3% and 40.5% for PM2.5 and PM10, respectively in winter and 39.4% and 35.2%, respectively in summer. Secondary ions such as sulfate, nitrate and ammonium accounted for the major part of the total ionic species. Sulfate was the most abundant species followed by nitrate. Overall, a regional pollution tendency was shown that there were higher concentrations of sulfate, nitrate and ammonium in Guangzhou City than those in the other PRD cities. Significant seasonal variations were also observed with higher levels of species in winter but lower in summer. The Asian monsoon system was favorable for removal and diffusion of air pollutants in PRD in summer while highly loading of local industrial emissions tended to deteriorate the air quality as well. NO3^-/SO4^2- ratio indicated that mobile sources have considerably contribution to the urban aerosol, and stationary sources should not be neglected. Besides the primary emissions, complex atmospheric reactions under favorable weather conditions should be paid more attention for the control of primary emission in the PRD region.

Heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta

Molluscs are able to accumulate heavy metals and impose health hazard to consumers. The main objective of the present study is to investigate the heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta. Fourteen species of edible molluscs were purchased from six markets in Hong Kong and Guangdong Province. The fresh of these biota were tested for their cadmium (Cd), copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), chromium (Cr), antimony (Sb) and tin (Sn) concentrations (based on wet weight). The results indicated that amongst the 14 edible molluscs, only Cd, Pb, Ni, Cr, Sb and Sn concentrations in three species (Ruditapes philippinarum, Perna viridis and Hemifusus tuba) were within the local regulatory limits. Over 60% of bivalve species exceeded maximum permitted levels of Cd (2 mug/g) and Cr (1 mug/g), while over 40% of gastropod species exceeded the maximum levels of Sb (1 mug/g) and Cr (1 mug/g). Most of the samples collected from Hong Kong had significantly higher contents of Pb and Sb, but similar levels of Cd, Cu and Zn when compared with samples collected across the border ( p < 0.05; p 0.01; p < 0.001 respectively). In general, the molluscs purchased in Guangdong markets had higher metal contents than those purchased from the Hong Kong markets. When compared with the Provisional Tolerable Weekly Intake or Maximum Acceptable Daily Load recommended by FAO/WHO Expert Committee on Food Additives, Cd levels of five species (Anadara ferruginea, Pinna pectinata, Chlamys nobilis, Babylonia lutosa and Hemifusus terntanus) and Cr levels of seven species ( Anadara ferruginea, Paphia undulata, Pinna pectinata, Babylonia lutosa, Hemifusus terntanus, Cymbium melo and Cipangopaludina chinensis) were higher than both the human daily acceptable limits (for Cd and Cr respectively) and the local regulatory levels (for Cd and Cr respectively).

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.

Evidences and implications of vegetation damage from ceramic industrial emission on a rural site in the Pearl River Delta of China

Community structure characteristics and vegetation damage degree were investigated and analyzed in a forest around village, which had been long term exposed to ambient atmospheric pollution stress, to study the influence of airborne pollutant emissions from the concentrated ceramic industries on vegetation. Field survey was carried out in a semi natural secondary forest on hilly land, Nanhai District of Guangdong Province, for the tree layer in ten quadrates with the total area of 10 × （10 m×10 m）, and for shrub and herb layers in eight subquadrates with the total area of 4 × （5 m×5 m）. Results showed that exotic Eucalyptus exserta and Eucalyptus urophylla were dominated over the community, followed by native tree species, Scheffiera octophylla and Bambusa gibba, with the importance value （Iv） of 26.75, 17.08, 16.27 and 11.50, respectively. Among all tree species, Eucalyptus exserta and Pinus massoniana were most severely damaged with nearly 100% damaged rate. Bambusa gibba and Dalbergia balansae were injured with damaged rate of 85.1% 68.3%, however, Eucalyptus urophylla, Celtis sinensis, Helicia cochinchinensis, Cinnamomum burmanni and Vitex negundo revealed moderate injuries （45%-57.5%）. Most of other indigenous species including Schefflera octophylla, Viburnum odoratissimum, Desmos chinensis, etc. showed less injured symptoms under the pollution stress. Compared with species in tree layer, damages of undergrowths were largely less. These results suggested that attention and concern should be paid on those introduced Eucalyptus species which had ever been widely used for forest restora tion in degraded hilly lands of south China since 1970-1980s, due to their last growing aspect, The results also demonstrated the potentials and perspectives by developing native species as target plants for restoration of degraded area at similar polluted location, which may provide scientific base for scientists to study and understand the functional aspects of native species and process-based interactions with pollution stress.

Impact of the Built Environment on the Spatial Heterogeneity of Regional Innovation Productivity:Evidence from the Pearl River Delta,China

With the global economy increasingly dependent on innovation,urban discourse has shifted to consider what kinds of spatial designs may best nurture innovation.We examined the relationship between the built environment and the spatial heterogeneity of regional innovation productivity(RIP)using the example of China's Pearl River Delta(PRD).Based on a spatial database of 522546 patent data from 2017,this study proposed an innovation-based built environment framework with the following five aspects:healthy en-vironment,daily interaction,mixed land use,commuting convenience,and technology atmosphere.Combining negative binomial regression and Geodetector to examine the impact of the built environment on RIP,the results show that the spatial distribution of innovation productivity in the PRD region is extremely uneven.The negative binomial regression results show that the built environment has a significant impact on the spatial differentiation of RIP,and,specifically,that healthy environment,mixed land use,commuting convenience,and technology atmosphere all demonstrate significant positive impacts.Meanwhile,the Geodetector results show that the built environment factor impacts the spatial heterogeneity of RIP to varying degrees,with technology atmosphere demonstrating the greatest impact intensity.We conclude that as regional development discourse shifts focus to the knowledge and innovation economy,the innovation-oriented design and updating of built environments will become extremely important to policymakers.

Changes in forest biomass carbon stock in the Pearl River Delta between 1989 and 2003

Forest ecosystems play a significant role in maintaining climate stability at the regional and global scales as an important carbon sink.Regional forest carbon storage and its dynamic changes in the Pearl River Delta have been estimated using the continuous biomass expansion factor(BEF)method based on field measurements of forests plots in different age classes and forest inventory data of three periods(1989–1993,1994–1998,1999–2003).The results show that regional carbon storage increased by 16.76%,from 48....

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.

Legislation on protection of drinking water sources and local management practices in the Pearl River Delta region of China

The protection of drinking water sources is vital to urban development and public health.In this study,the current situation of the mandatory protection area for drinking water source in the Pearl River Delta region was investigated using a method combining Google Earth with the field survey.The gaps between management practices and legislation requirements were analyzed.Finally,several countermeasures for water resource protection were proposed as follows:to promote delineation in a more scientific way,to safeguard the sanctity of the law,to make better plan on water saving,and to encourage public participation in supervision and management.

Characterization of Soil Available Nitrogen in the Major Vegetable Production Areas of Pearl River Delta,China

A macro scale survey was performed to investigate the content of soil available nitrogen (N) and its spatial distribution in the main vegetable production areas of the Pearl River Delta.Preliminary enrichment-deficient index of available N was then developed,which was a base for increasing fertilizer application efficiency and vegetable yield as well as for constructing soil testing and fertilizing formula.In general,most of the vegetable growth areas in Pearl River Delta were N-deficient or medium-N-deficient.There was 30%-62% increase in yield of Chinese cabbage on the N-deficient soil after application of N; when soil available N content was less than 145 mg/kg,the yield increased with application of N fertilizer at a rate of 60-70 kg/hm2.

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.

A Closure Study of Aerosol Hygroscopic Growth Factor during the 2006 Pearl River Delta Campaign

Measurements of aerosol physical, chemical and optical parameters were carried out in Guangzhou, China from 1 July to 31 July 2006 during the Pearl River Delta Campaign. The dry aerosol scattering coefficient was measured using an integrating nephelometer and the aerosol scattering coefficient for wet conditions was determined by subtracting the sum of the aerosol absorption coefficient, gas scattering coefficient and gas absorption coefficient from the atmospheric extinction coefficient. Following this, the aerosol hygroscopic growth factor, f（RH）, was calculated as the ratio of wet and dry aerosol scattering coefficients. Measurements of size-resolved chemical composition, relative humidity （RH）, and published functional relationships between particle chemical composition and water uptake were likewise used to find the aerosol scattering coe？cients in wet and dry conditions using Mie theory for internally- or externally-mixed particle species [（NH_4）_2SO_4, NH_4NO_3, NaCl, POM, EC and residue]. Closure was obtained by comparing the measured f（RH） values from the nephelometer and other in situ optical instruments with those computed from chemical composition and thermodynamics. Results show that the model can represent the observed f（RH） and is appropriate for use as a component in other higher-order models.

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.

Frequency, Duration and Intensity of Dengue Fever Epidemic Risk in Townships in Pearl River Delta and Yunnan in China, 2013

Dengue fever （DF）, one of the neglected tropical diseases also known as breakbone fever, is a mosquito-borne disease common in the tropics and subtropics. Dengue fever is transmitted primarily by A.aegypti, resulting in infection with any of four distinct but closely related virus serotypes. The majority of infected people experience a self-limiting clinical course. A small proportion of cases develop into life-threatening Dengue Hemorrhagic Fever or Dengue Shock Syndrome.

ATMOSPHERIC BOUNDARY LAYER CONCEPT MODEL OF THE PEARL RIVER DELTA AND ITS APPLICATION

Based on the geographical circumstance, climate and the boundary layer meteorology features of the Pearl River Delta, a boundary layer concept model of the Pearl River Delta was built. The concept model consists of four fundamental factors that affect the boundary layer meteorology of the Pearl River Delta and can convincingly explain the reason of the air quality change in the Pearl River Delta. The model can be used to the diffusion capability analysis, the air pollution potential forecasting or haze forecasting, etc.

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.

Gene abundances of AOA,AOB,and anammox controlled by groundwater chemistry of the Pearl River Delta,China

Ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),and anaerobic ammonia-oxidation(anammox)bacteria are very important contributors to nitrogen cycling in natural environments.Functional gene abundances of these microbes were believed to be well relevant to N-cycling in groundwater systems,especially in the Pearl River Delta(PRD)groundwater with unique high intrinsic ammonia concentrations.In this research,20 sediment samples from two in the PRD were collected for porewater chemistry analysis and quantification of N-cycling related genes,including archaeal and bacterial amoA gene and anammox 16S ribosomal Ribonucleic Acid(rRNA)gene.Quantitative Polymerase Chain Reaction(qPCR)results showed that gene abundances of AOA,AOB,and anammox bacteria ranged from 3.13×10^(5)to 3.21×10^(7),1.83×10^(4)to 2.74×10^(6),and 9.27×10^(4)to 8.96×10^(6)copies/g in the sediment of the groundwater system,respectively.Anammox bacteria and AOA dominated in aquitards and aquifers,respectively,meanwhile,the aquitard-aquifer interfaces were demonstrated as ammonium-oxidizing hotspots in the aspect of gene numbers.Gene abundances of nitrifiers were analyzed with geochemistry profiles.Correlations between gene numbers and environmental variables indicated that the gene abundances were impacted by hydrogeological conditions,and microbial-derived ammonium loss was dominated by AOA in the northwest PRD and by anammox bacteria in the southeast PRD.