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.

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.

ON FEATURES OF TOWN DEVELOPMENT IN THE ZHUJIANG RIVER DELTA SINCE 1978

since 1978, rural urbanization has been accelerated in the Zhujiang (Pearl) River Delta because of the rapid development of commodity agriculture, industrialization and tertiary industry. Its natural urban population increase had been mostly mechanical before now, and the towns have been transformed from traditional centers into those serving various functions, particularly industrial ones.In the Zhujiang River Delta, population density and the level of economic changes are high in central areas, and low in outlying area, but on the other hand, urban population has increased slowly in central area and fast in outlying area. In the central areas more industrial towns emerge. So the gap has been greatly reduced. The reform of the construction of the region’s economy, the improvement of transportation, the adjustment of the standard of town setting have promoted the distribution of the towns in the Zhujiang River Delta from being centralized to balanced.

SEA LEVEL RISE OF THE ZHUJIANG RIVER DELTA AND NEOTECTONICS

A linear regression analysis of 28 selected tide-gauge stations of the Zhujiang Estuary shows that there has been a tendency of local sea level rise at a rate of 2.028 mm per year. The origin of the variation is significantly attributed to the local tectonic movement of discrepant fault-block. Based on this, four types of relative local sea level changes are classified. According to calculation, half of the fertile land, or 800 km2 of the delta plain will have been submerged by sea water by about 2040. This will yield a significant influence on the economic construction and human activities.

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.

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.

THE RELATIONSHIP BETWEEN THE ENVIRONMENTAL CHANGE OF THE ZHUJIANG RIVER DELTA IN HOLOCENE AND ITS CULTURAL ORIGINS AND PROPAGATION

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PROBLEMS OF THE AQUATIC ENVIRONMENT AND COUNTERMEASURES IN RAPID ECONOMIC DEVELOPMENT IN THE ZHUJIANG RIVER DELTA

The Zhujiang (Pearl) River Delta is the rapid economic development region in China since the opening and reform door policy was carried out in 1978. Being the rapid development of industry and city, the impact on the aquatic environmental quality was sig

ON ENVIRONMENTAL CONDITIONS OF THE GENESIS OF TORNADO IN THE ZHUJIANG RIVER DELTA IN SPRING

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Daily Changes of Spatial Patterns of Meteorological Elements over Pearl River Delta Based on GIS and MM5

The spatial distribution of meteorological elements is important for understanding the regional meteorology and climate changes. However,previous studies rarely focused on the daily changes of the spatial patterns of meteorological elements due to the limitation of remote sensing(RS) techniques and traditional meteorological methods. In this paper,the regional meteorological elements were simulated by the fifth-generation non-hydrostatic Mesoscale Model(MM5) ,and the spatial patterns of meteorological elements and their diurnal variations were analyzed in landscape level over the Pearl(Zhujiang) River Delta(PRD) ,China. The results showed that there were several centers of urban heat islands,cold islands,dry islands,wet islands,high wind over the PRD at noon. The diurnal changes of Moran I of meteorological elements were obvious and they reached the extremum at noon and 2-3 hours after the sunrise. The landscape indices of meteorological elements,such as area-weighted mean Fractal Dimension Index(FRAC_AM) ,Landscape Shape Index(LSI) ,Shannon's Diversity Index(SHDI) and Contagion Index(CONTAG) ,were more variable at about the sunrise,noon and sunset. The occurrence of wave crests and vales of landscape indices was affected by the surface net radiation,turbulence and local circumfluence. The spatial patterns of meteorological elements correlated well with the land surface,thermal exchanges and local circumfluence. A new approach combining GIS,RS and numerical simulations technologies and the landscape ecology method was presented to analyze spatial patterns of meteorological elements,which may be useful for studying global and regional climate changes.

THREE-DIMENSIONAL MESOSCALE MODELING OF METEOROLOGICAL FIELDS OVER ZHUJIANG(PEARL)RIVER DELTA

The CSU-RAMS-2A was used to simulate the meteorological fields over the Zhujiang River Delta in South China. Initialized from a horizontally homogeneous atmosphere,real topography and inhomogeneous surface boundary condi- tions,the model was run with thermal and terrain forcing.The modeling results of winter and summer cases are com- pared with those observed.The similarity of the predicted distributions of winds,temperatures and humidities to the ob- served patterns permits us to conclude that the mesoscale distribution of meteorological elements for the two study dates is the result of the thermal and dynamical forcing by the underlying surface and topography.

海相砂岩油藏沉积微相特征及对剩余油的控制——以南海东部X油田为例

X油田为南海东部典型的海相砂岩油田,开发中后期剩余油特征不清晰,充分利用动静态资料,展开沉积微相及动油水界面研究。结果表明:研究区油藏范围内发育水下分流河道主体、河道侧缘、河口坝、远砂坝及分流间湾等微相,河道主体厚度较大,动油水界面在构造高部位趋于水平;河道侧缘、河口坝、远砂坝等砂体储层较薄,横向连续性受物源方向控制,在开发中后期,来水方向受砂体展布方向控制,波及程度较弱,从而产生剩余油富集区。

珠江三角洲土地利用变化与工业化和城市化的耦合关系

在分析珠江三角洲1990～2000年土地利用变化趋势和特征的基础上,根据土地利用的综合变动系数将珠江三角洲划分为4种土地变化类型,即剧变型、缓变型、相对稳定型和稳定型,并总结了不同变化类型的特征.进一步研究了工业化、城市化发展阶段与土地利用变化类型的关系,结果显示,处于不同工业化、城市化阶段的县市,其土地利用变化也明显不同,且与工业化、城市化进程和状态具有一定的内在关系;最后对产业非农化、城市化与土地利用变化的耦合系数进行了研究,发现各市县的产业非农化、城市化和土地利用变化的耦合系数,与土地利用的综合变动系数具有很高的一致性,按照产业非农化、城市化和土地利用变化耦合系数,在一定程度上可以判断土地变化的类型.

珠江三角洲及河网形成演变的数值模拟和地貌动力学分析：距今6000-2500a

珠江三角洲是我国一个极其复杂的大尺度河口系统,具有独特的河网体系和河口湾.为了探讨距今6 000 a以来珠江三角洲和河网的形成演变,提出一个长周期动力形态模型(PRD-LTMM)并讨论长周期模拟方法的建模和验证思想,重建了距今6 000 a海进盛期的古珠江河口湾的水下地形作为模型的初始边界.在模型中考虑的驱动力和控制因素包括代表潮、河流流量、泥沙输入、海平面变化、沉积物压实率及新构造运动等.分析和计算了三角洲总沉积量、有效堆积空间和沉积速率,用于模型控制和校验.应用必要的模型约减技术,实际模拟了长周期模型.34个14C测年钻孔资料初步验证了模型的正确性,一些古文化遗迹证据可以印证模拟结果.地貌动力学分析进一步论证了计算结果的合理性,阐述了模型输出的地学意义.现阶段的研究揭示出海进盛期以来珠江三角洲的时空演进过程具有一些与已有研究成果大不相同的新的特征.提出距今6 000 a以来珠江三角洲等沉积时间线和若干沉积模式.珠江三角洲发育演变及其特征在很大程度上源自其继承性的地质地貌构造所造成的独特的古海湾构造形态及其对河流和海洋动力分布的重塑.珠江河口的“门”及其双向射流动力体系对珠江三角洲和河网主干,特别对口门的形成演变起了控制性的作用,模拟结果还表明,古珠江河口湾中散落的众多基岩岛丘边沿沉积是影响珠江三角洲长期演变的重要因素.

珠江三角洲地区地下水锰的分布特征及其成因

为了解珠江三角洲地区地下水中锰的含量及其成因,笔者采集并分析了352组地下水样和13组地表水样。结果表明:珠江三角洲地区地下水的锰含量在未检出至8.32mg/L之间,平均浓度为0.34mg/L,超标率达49.4%。在该区9个地级市范围都存在地下水锰超标现象。区内地下水的锰含量与总溶解固体(TDS)、化学需氧量(COD)以及HCO3ˉ都呈极显著的正相关关系,而与Eh呈极显著的负相关关系。珠江三角洲地区地下水中锰含量的分布与该地区的工业化程度以及所处的补、径、排条件密切相关。影响该地区地下水锰含量分布的因素主要有氧化还原环境、酸碱条件、地下水的总溶解固体、上覆盖层性质、地下水径流条件以及含水层介质等。

珠江三角洲潜在生态风险:土壤重金属活化

珠江三角洲典型土壤模拟酸雨提取实验表明,土壤酸缓冲能力为菜园土大于水稻土大于赤红壤。酸化过程早期,铝铁胶体吸附共沉淀导致重金属溶出量增长不明显甚至下降;进一步酸化时,多数元素溶出量与加入酸量呈显著正相关。计算表明,在pH=4.5的酸雨作用下,溶液中Hg、Mn、Pb、Fe(以Fe2O3表示)浓度已超出II级地表水标准,Cu、Zn大大高于渔业用水标准。可见,土壤元素活化溶出对水体生态环境有潜在的危害。

珠江三角洲地区地下水环境背景值初步研究

在分析对比国内外研究方法的基础上,选择数理统计方法,运用国际通用统计软件SPSS,对珠江三角洲地下水水质指标TDS、Cl-、SO24-、TFe环境背景值进行研究,并初步探讨了它们的空间分布规律及控制因素。分析认为地形地貌、区域水动力条件及海水入侵等因素对研究区浅层地下水指标的空间分布起主要控制作用。其结果为评价珠江三角洲地区地下水污染状况提供科学的依据。

近20年珠三角城市群城市空间相互作用时空演变

利用改进的引力模型和潜力模型,结合GIS空间分析方法,从地级市和县域两个空间尺度分析了近20 a珠三角地区城市间相互作用的时空演变。结果表明:珠三角地级城市空间联系总体逐步加强,并充分体现出广州的中心城市地位;县域尺度上,空间联系强度较大的主要是各地市市区之间及广-佛都市区的县市间和各地市市区与其所辖县市之间,其它县市间联系强度则较小;珠三角核心区内大部分县市之间联系总体呈逐渐增强趋势,核心区外的县市之间及其与核心区内的县市间联系强度有升有降,规律性不明显。广-佛都市区和深圳-东莞-惠州都市区的城市潜力较大且变动较大,对外辐射带动作用强,其它城市潜力相对较小且变化不明显;珠三角城市潜力的区域不平衡态势明显,城市潜力的空间分异和空间辐射的特征与演变规律明显。