澳门的城市性质及其在我国城市体系中的地位和作用

文章分析了澳门城市形成和发展的历史基础,其性质和功能特点,当前的经济结构状况及其发展条件。在此基础上指出了它的发展方向,以及在中国恢复行使主权和特别行政区高度自治(“一国两制”)条件下的区域经济一体化的途径。     

Forest conversion, conservation and forestry in Cross River State, Nigeria

This paper presents new data on the rate and patterns of loss of tropical moist forest cover to agriculture in Cross River State, Nigeria. Data from sequential aerial photographs and field surveys are used to derive an estimate of forest loss of 0.6 per cent per year. This rate is relatively modest, yet current conservation and forestry policy in the area is based on assumptions of rapid conversion of forest. The implications of these findings for debates about conservation and policy are discussed.     

城市地表灰尘重金属研究进展及展望

城市地表灰尘是城市环境科学研究的对象之一,在对国内外有关城市灰尘概念界定研究成果进行总结的基础上,对城市地表灰尘提出新的概念和新的认识。城市地表灰尘是城市生态环境中具有环境指示作用的地表颗粒物,是含有重金属、多环芳烃等多种污染物的源与汇。对国内外地表灰尘重金属的含量水平、时空分布特征、迁移循环、赋存形态及生物有效性等方面的研究成果进行比较系统的阐述;灰尘中重金属的来源识别的方法主要有GIS空间分析,元素示踪技术,统计学方法等。并提出在今后的研究中应进一步完善城市地表灰尘中重金属的时间变化规律、地表灰尘在环境中的滞留时间、粒径的划分以及区域人体健康影响及风险评估模型优化四个方面的研究。     

A quantitative assessment of the distribution and extent of urban clusters in China

Urban clusters are the expected products of high levels of industry and urbanization in a country, as well as being the basic units of participation in global competition. With respect to China, urban clusters are regarded as the dominant formation for boosting the Chinese urbanization process. However, to date, there is no coincident, efficient, and credible methodological system and set of techniques to identify Chinese urban clusters. This research investigates the potential of a computerized identification method supported by geographic information techniques to provide a better understanding of the distribution of Chinese urban clusters. The identification method is executed based on a geographic information database, a digital elevation model, and socio-economic data with the aid of ArcInfo Macro Language programming. In the method, preliminary boundaries are identified according to transportation accessibility, and final identifications are achieved from limiting city numbers, population, and GDP in a region with the aid of the rasterized socio-economic dataset. The results show that the method identifies nine Chinese urban clusters, i.e., Pearl River Delta, Lower Yangtze River Valley, Beijing-Tianjin-Hebei Region, Northeast China Plain, Middle Yangtze River Valley, Central China Plains, Western Taiwan Strait, Guanzhong and Chengdu-Chongqing urban clusters. This research represents the first study involving the computerized identification of Chinese urban clusters. Moreover, compared to other related studies, the study's approach, which combines transportation accessibility and socio-economic characteristics, is shown to be a distinct, effective and reliable way of identifying urban clusters.     

Efficient use of resources: urban waste ash and soil fertility on the Jos Plateau, Nigeria

Waste disposal constitutes an acute problem in numerous African cities. One solution could lie in the recycling of the nutrient-rich waste into agriculture taking place in and around cities. Farmers involved in vegetable production around Jos, Nigeria, have developed a sophisticated soil fertility management strategy combining inorganic fertilizers, manure and urban waste ash. This paper: (1) investigates the socio-economic constraints linked to obtaining scarce organic inputs, particularly urban waste ash and the health hazards (particularly heavy metal contamination of soil and crops) caused by using this ash and (2) suggests ways to improve use of this important resource.     

中国城市群分布及范围的定量评价(英文)

Urban clusters are the expected products of high levels of industry and urbanization in a country, as well as being the basic units of participation in global competition. With respect to China, urban clusters are regarded as the dominant formation for boosting the Chinese urbanization process. However, to date, there is no coincident, efficient, and credible methodological system and set of techniques to identify Chinese urban clusters. This research investigates the potential of a computerized identification method supported by geographic information techniques to provide a better understanding of the distribution of Chinese urban clusters. The identification method is executed based on a geographic information database, a digital elevation model, and socio-economic data with the aid of ArcInfo Macro Language programming. In the method, preliminary boundaries are identified accord-ing to transportation accessibility, and final identifications are achieved from limiting city numbers, population, and GDP in a region with the aid of the rasterized socio-economic dataset. The results show that the method identifies nine Chinese urban clusters, i.e., Pearl River Delta, Lower Yangtze River Valley, Beijing-Tianjin-Hebei Region, Northeast China Plain, Middle Yangtze River Valley, Central China Plains, Western Taiwan Strait, Guanzhong and Chengdu-Chongqing urban clusters. This research represents the first study involving the computerized identification of Chinese urban clusters. Moreover, compared to other related studies, the study’s approach, which combines transportation accessibility and socio-economic characteristics, is shown to be a distinct, effective and reliable way of identifying urban clusters.     

State Legitimacy and the Unending Crisis of Petrol Subsidy Reforms in Nigeria

Why would the citizens of an oil-producing state continually resist reform-induced petrol price increases, even when subsidy payments are proved to be a serious threat to the capacity of the state to deliver its core constitutional mandates? In this paper, we tackle this question by contending that the difficulty in petrol subsidy implementation in a country like Nigeria has more to do with the clear lack of state legitimacy and public trust, and the recorded cases of political instability entrenched by forced attempts at reforms. By contextualizing the reform efforts in Nigeria within the framework of the relationship between state legitimacy and reforms, we are able to provide valid insights to a broader understanding of the “whys” of public resistance to the authority of the state to enforce reform. The Nigerian case, as revealed in this article, provides evidence of a shift in paradigm from the conventional and dominant Weberian emphasis of state legitimacy around the nature and sources of state authorities to a more functional context of citizens’ perception of the governance process as a source of legitimacy.     

塔克拉玛干沙漠腹地起伏地形近地层微气象特征

利用2018年10月8日至2019年1月31日塔克拉玛干沙漠腹地起伏地形上高大沙垄高点和低点的温度、相对湿度、风速和大气压同步观测资料,对比分析沙漠起伏地形上秋冬季的微气象特征。结果表明:塔克拉玛干沙漠腹地高大沙垄造成的地形起伏,使得沙垄高点和沙垄低点气温、比湿和风速日变化差异明显。沙垄高点和沙垄低点气温差异主要体现在夜间,与沙漠腹地夜间存在逆温现象有关,表现出沙垄高点气温明显高于沙垄低点,观测期气温差异平均值为6.6 ℃。沙垄低点气温日较差高于沙垄高点。2018年10、11、12月,气温随高度变化出现逆温现象与沙垄高点气温高于沙垄低点气温在时间上相互对应。两个站点比湿较小,平均比湿分别为0.68 g·kg^-1和0.99 g·kg^-1。比湿日变化趋势随季节发生显著变化,主要与大气稳定度增加、冬季水汽增多及夜间逆湿现象逐渐显著相关。地形位置较高的沙垄高点风速比沙垄低点大,风速差异主要体现在夜间。2018年11月2、14、15、20日和2019年1月30日,沙垄高点风速维持在1.9~4.6 m·s^-1,平均3.2 m·s^-1,沙垄低点风速维持在0.8~4\^5 m·s^-1,平均2.5 m·s^-1。     

1936年以来南京城市空间扩展特征研究

城市交通网络的发展是城市空间扩展的重要表征和驱动力。以1936—2015年间6个代表性年份的城市交通地图为数据源,提取相应年份南京城市轴线图,利用基于空间句法的整合度、城市扩张强度（SS-EII）和智能度指数,分析1936年以来南京城市空间扩展趋势和特征,划分演化阶段,并分析城市加速扩张阶段的空间扩展质量。结果表明：① 南京城市空间扩展大体经历了滞缓（1936—1971年）、复兴（1971—1982年）和加速（1982—2015年）三个阶段,逐渐突破老城区,向西南、东北、南部和西北实现全方位空间扩展,形成多中心空间结构。② 加速阶段空间扩展质量总体较高,交通网络建设逐渐与用地扩张相协调,并开始引导城市空间多中心扩散,但各中心间有机联系不足,导致城市空间整体性和空间效率有所降低。③ 应进一步加强多中心间的交通联系,促进人口、经济有机疏散,并提高城市空间整体性。     

中国城市群城市用地扩张时空动态特征

认识城市群城市用地扩张特征、扩张质量及景观生态效应等综合信息将有助于城市群空间高质量发展规划与决策。选取10个不同发育等级的城市群作为研究对象,综合运用城市用地扩张强度指数、城市用地扩张强度差异指数、景观扩张指数、景观格局指数,分析1990—2015年期间城市群城市用地扩张时空特征及景观生态效应,并构建人口、经济与城市用地协同发展指数,据此分析城市用地扩张中“人—地”关系协同程度。结果表明：① 1990—2015年,各个城市群城市用地面积持续增加,建成区的范围不断扩大,扩张强度呈现“上升—下降”的趋势;在2010年之前成熟型城市群的扩张强度最高,2010年之后培育型城市群成为扩张强度最高的类型。② 城市群城市用地扩张总体上呈现不均衡布局的趋势,高速扩张区域主要分布在沿海地区。从全国视角来看,东部高于中、西、东北部,整体城市群快速扩张的中心由东向西移动。③ 城市群城市用地空间扩张模式表现出边缘式和飞地式两种空间扩张模式并存,不同发育等级之间具有明显差异性,成熟型城市群的空间结构较为稳定,其他两种类型的城市群空间结构初具雏形或尚未形成。④ 城市群城市用地扩张“吞没”了郊区和农村地区,破碎化程度、形状的复杂程度较高,景观格局表现出不稳定。⑤ 城市群“人口—土地”协同程度逐步增强,“经济—土地”协同程度整体较高,整体上表现出城市用地扩张质量有所提升。新时期城市群城市用地应严格控制扩张规模,加快中小城市的发展,促进城市群城市用地扩张均衡发展,为城市群国土空间高质量发展提供重要参考。     

毛乌素沙地布寨淖尔下风向沙化湖滨地表沉积物理化特性

布寨淖尔湖是鄂尔多斯高原毛乌素沙地腹地的代表性盐湖,其东南部分布着平坦裸露的沙化湖滨\,湖岸沙丘及半固定沙丘,地表均沉积有大量沙物质与粉尘,这些松散富盐物质在风力侵蚀作用下常形成盐碱尘暴,威胁下风向区域的生态环境安全。研究了布寨淖尔湖东南部区域2.5 km范围内地表沉积物的土壤粒度与理化特性,旨在为盐碱尘暴源区的防治与生态治理提供基础科学参考。结果表明:布寨淖尔湖滨裸露地表沉积物以粗砂、中沙和细砂为主;从湖心沿东南方向等距离(0.5 km)采样,距湖心越远,粗砂和细砂含量逐渐减小,极细砂、粉砂和黏土含量逐渐增加,中砂含量无明显变化。地表沉积物含水率、容重随与湖心距离的增加逐渐增加,pH值、全盐量及电导率则呈逐渐减小趋势;沉积物阳离子以Na⁺为主,阴离子以Cl^-为主,其次为SO₄^2-、HCO^-₃。整体看,区内地表碱化较为严重,区域下风向土壤理化特征呈明显有规律变化趋势,湖滨地表土壤有明显风蚀迹象,可能是盐碱尘暴与湖岸沙丘形成的重要物源区。     

The role of cultural and creative services in the evaluation of the world urban system

Traditionally, academic evaluation of the world urban system has been based on economic approaches and focused on primary cities. However, the recent convergence between economic and cultural spheres, known in specialist literature as the ‘new economy’ or ‘cognitive–cultural capitalism’, requires the inclusion of secondary cities and cultural parameters, such as creative and cultural services, to obtain knowledge of the world urban system with greater accuracy. Accordingly, the authors have developed the Synthetic Index of Cultural Components (objective 1). Subsequent statistical treatment through a principal component analysis and a cluster analysis not only shows a representation of the multifunctional character of the world urban system (objective 2) but also identifies the cultural specializations that urban planners use to position cities worldwide (objective 3). The results demonstrate that the reputation of a city derives not only from its productive economic character but also from other cultural creative services that give meaning to its multidimensional perspective. The authors conclude that these services are empirically valid when the cultural dimension is measured, as they are illustrative of the cultural mechanisms that help cities to supply symbolic, experiential, and cultural capital, all of which are vital in the competitive context of globalization.     

基于汽车产业供应链体系的中国城市网络特征研究

结构特征与权力等级是城市网络的重要要素。基于“产业-区位”视角,通过对2012年中国汽车产业供应链体系分析,凝炼中国城市网络特征。研究发现：① 基于汽车产业供应链体系的中国城市网络表现出明显的“低密度-多核心、高聚类-少趋同”的结构特征。② 城市网络的结构特征与权力等级存在显著“悖论”,即城市节点的网络地位不仅取决于链接城市的数量,还需考虑关联网络的空间属性和资本容量。③ 城市网络权力等级中既包括上海、重庆等领导核心城市,也包括广州、芜湖等中心集约城市和苏州、成都等权力门户城市,说明转变中心性与转变控制力不仅能有效揭示中国城市网络节点的真实权力属性,也更符合经济现象的地理空间非均衡规律。④ 重庆、上海、天津、长春、北京、十堰等领导核心城市并未完全锁定中国六大汽车产业集聚区,其中长三角地区网络权力最突出,珠三角地区网络权力最弱。     

Palaeolimnology and its developing role in assessing the history and extent of human impact on lake ecosystems

This Special Issue was produced as an output from the EU Integrated Project Euro-limpacs which aimed to evaluate the impacts of global change on European freshwater ecosystems using a combination of approaches, including monitoring, experiments, modelling and palaeolimnology. The papers focus on the last of these approaches. They examine the role of lake sediment records in determining reference conditions for a range of environmental pressures including acidification, eutrophication, metal pollution, organic carbon and sediment accumulation rates. The findings are especially relevant to the European Union’s Water Framework Directive which requires an assessment of lake ecological status based on deviation from reference conditions. The contributions consider a range of issues relating to the use of palaeolimnological data in defining reference conditions and lake status including human versus natural variability, concepts of pristine and reference conditions, shifting baselines, and quantification of degree of change. This introductory paper sets the context for the volume by briefly describing how palaeolimnology has evolved as a science, able now to contribute uniquely to the understanding of lake ecosystem change, especially with respect to the role of human activity over recent decades and centuries.     

信息技术对城市居民出行特征的影响——以南京为例

信息技术在城市生产、生活与管理中的加速应用不仅促使城市空间结构正在发生转型,也影响了城市居民的活动空间特征。论文基于社会调查,以南京为例,考察了信息技术对城市居民交通出行行为特征的影响。总体而言,南京城市居民家庭在接入信息技术上已经有了长足的发展,接入互联网能力迈入快速增长期。但由于各城区间、各郊区间的信息接入能力存在显著差异,这必然会影响居民的出行行为。研究表明:在家办公的出现减少了日常的工作出行。信息网络对居民日常出行的引导作用日益突出,并出现了部分替代。城市居民家庭的交通通讯费用大幅增长,上网时间增长较快,而城区更为明显。     

Dynamics and driving factors of late Holocene gullying in the Main Ethiopian Rift (MER)

The issue of determining the driving factors in gullying, apart from land use, is somewhat lagging in comparison with the study of their physical modelling and control technology. Available information focuses on the basic ideas of climatic control, anthropic determinism and internal “authigenic” dynamics. High resolution chronology of cyclic systems, common in extensively gullied areas, can provide a clue to the weight of each factor. This paper reports a study of this kind, focusing on two gully catchments in the Main Ethiopian Rift (MER), but backed by an extensive regional survey. By integrating tracing and correlation of unconformity-bounded stratigraphic units and soils with radiocarbon dating, a detailed chronology was obtained for the last 5000 years. This could be compared with proxy climate reconstructions of similar detail. Clear evidence of climatic control emerged; gully filling is triggered by decreased stream transport capacity and increased sediment supply during transitions towards drier climate phases, while gully entrenchment appears to take place at the start of moist intervals, for the reverse reasons. A broader consideration of geological setting, however, puts forward a more general interpretation. These gullies actually formed, in the beginning, as part of the land surface response to sudden, very recent tectonic events, which created accommodation space for temporary sediment stores. They should then be seen in the frame of the Discontinuous Ephemeral Stream (DES) concept; as such, they are intrinsically non-linear and complex phenomena, whose response is linearized by a strong climatic–vegetational forcing, acting on both channel flow and sediment supply.     

2000年以来南京城市三维空间扩展特征

以南京市建成区为例,基于四期城市三维模型,运用城市天际线、城市体积及分维数、城市三维重心、高层建筑的数量与占地面积的关系等方法从多角度分析2000年以来南京城市三维空间增长特征.研究表明:南京城市天际线起伏明显,西—东方向的形态由2000年的“一高两低三峰”演化为2012年的“中部、西部双峰耸立,东部较为平缓”的格局;城市体积处于持续增长的态势,其中2000-2004年是体积增长最快的时期,增长率为51％,体积分维数在不断变大,表明城市扩展在不断从二维向三维形态发展演变;三维重心平面投影的移动方向从东南转向西,反映了三维城市的发展方向主要为城市南部和西部地区;2000年城市立体形态发展为弱金字塔阶段,至2012年,在高楼密集的中心城区已经发展至均衡金字塔阶段甚至在向穹隆顶阶段过渡.     

长沙城市空间破碎化的格局特征及其影响因素

空间破碎化是城市空间结构研究亟待深化的重要课题。从形态、联系以及功能3个维度构建城市空间破碎化测度指标,并运用地理探测器模型,探讨长沙城市空间破碎化的格局特征及其影响因素。主要结论：① 城市空间破碎化可从形态分割、联系阻隔、功能失序三方面进行测度,形态分割可用平均地块面积指数表征,联系阻隔可用平均阻抗指数刻画,功能失序可用功能多样指数、邻接冲突指数来反映;② 长沙城市空间破碎化呈现圈层式分异为主、扇形扩展分异为辅的格局特征,低破碎化区主要分布在城市核心区,高破碎化区沿着特定的扇面向外围扩展,且主要分布在大型封闭社区、工业园区、山地绿地及大型站场等区域;③ 长沙城市空间破碎化的空间分异是多因素综合作用的结果,其中海拔、坡度等自然因素是基础因素,土地价格、人口密度、设施投入是主导因素;④ 长沙城市空间破碎化治理可从突破市场供给约束、市场需求约束和设施丰度约束三方面着手,采取针对性调控对策,以最大程度地消减空间破碎化带来的负面效应。     

多重流空间视角下的中国城市网络空间结构特征及组织模式

城市关系网络化是城市体系结构发展的重要趋势,不同要素流空间网络下的城市体系在空间组织上不尽相同,依托单一要素对网络进行表征的结果具有明显的局限性。本文基于企业联系、科研合作、人口迁徙和引力模拟四类要素网络,从城市节点、路径联系、社区特征等角度剖析多重流空间视角下中国城市网络的外部空间特征与差异,并探究城市间联系的内在模式规律。结果表明：(1)多维数据源视角下构建的多重城市网络在空间组织上表现出相似稳定性和多元差异性的统一。(2)一定程度上依赖于基础设施运转的人流、物流等网络受到地理距离的约束较大,相邻地区的小团体特征明显,社区结构较强;而资金流、信息流等实体性较弱的要素则突破了这种地理限制,发生联系的重点在于目标城市对于要素流的吸引力,社区结构较弱。(3)目前全国城市联系形态上具有层级性和扁平化的双重特征,据此本文基于“管道-蜂鸣”模型提出“社区蜂鸣-守门员-区域管道”城市空间组织模式,这一模式对于阐述中国的城市联系特征具有较好的适用性,可在全国识别出10个核心守门员城市和8个类型区。