Demographic aspects of urbanization

Urban growth and urbanization can be defined, measured and studied in a variety of ways but there is little doubt that the demographic dimension is of paramount importance for both the general public and interested scholars. It seem appropriate that this aspect should be given a particular attention during the symposium organized during the International Geographical Congress as well as a special publication resulting therefrom. The present assay attempts to discuss the demographic issues at a very high level of generalization. The basic data used were derived from the latest UN estimates.     

The nature of urbanization in the gulf countries

This paper analyses the urban process in the oil producing countries of the Gulf. The mode of urbanization is identified as one characterized by an extreme case of primacy but with rates varying among the countries of the region. This pattern is related to the historical evolution of human settlements as affected by the local environmental qualities and the recent large scale development of urban infrastructures which favoured the already existing capital cities. The relative city growth rates are among the highest in the world but with a declining tendency which reflects expenditure patterns and the nature of the regional economies. The high growth rates are essentially due to massive foreign migration into the region and to extremely high natural increase rate — an abnormal condition in an urban process approaching saturation point. The role of these primate centres in the development of the region is undeniable and, furthermore, all indications suggest that this pattern of urban development will continue in the furture as it is, perhaps economically and politically less costly.     

主要发达国家地质信息服务的政策体系及其特点

信息服务政策是信息服务顺利实施的保障。美、加、澳和英国等主要发达国家的地质调查机构制定并执行了一系列的信息服务政策。这些政策规定了服务的对象、内容、定价、合作伙伴关系、信息发布、客户关系、服务质量等方面的行为准则,涵盖了实施信息服务涉及的所有主要行为,已经形成了比较完整的体系。从以下几个方面阐述了上述主要发达国家信息服务政策体系的特点:信息自由法、版权对地质信息服务的影响,比较完善的定价政策、价格体系和重视用政策、标准规范信息服务。     

Environmental and social aspects of underwater logging

Underwater logging is a relatively new concept in forestry that has significant economic benefits but also consequences for the environment and local communities. Underwater logging has traditionally been undertaken by divers. However, safety concerns mean that conventional harvesting methods using divers need to be replaced by more sophisticated mechanized harvesting techniques. This paper outlines the environmental and social aspects of underwater logging, highlighting issues that must be considered before any underwater harvesting operations are executed. While the economic reasons for harvesting underwater logs seem compelling, as do the associated social benefits, such as employment generation, there are significant environmental impacts of removing trees from reservoirs, as submerged trees serve as important ecological habitat for aquatic life. Due to the absence of any regulatory regimes encompassing underwater logging, we propose best-practice guidelines for underwater logging operations and suggest the need for a comprehensive sustainability framework based on internationally recognized criteria and indicators to ensure underwater logging operations are environmentally safe, socially beneficial and economically viable.     

Some qualitative aspects of the urban environment in developed countries

The quality of life in cities is a subject that has aroused considerable concern and fears, but treatment of the subject tends to have become distorted by pre-existing values and subsumed under broader questions. This paper concentrates on the city as an experienced place and focuses on three emerging areas of discussion. The first part deals with the shift from two-dimensional, plan-based proposals for the future to three-dimensional theories applied to the finer grain of future urban form. The second part deals with the increasing realisation of the cultural basis and manifestations of quality in urban life and the research on urban cultural innovation which this has encouraged, drawing evidence from the Council of Europe's 21-town cultural innovation project. The final section discusses the significance of dreams for the future in shaping the urban environment of the future. It points to the current vacuum in thinking on the subject and indicates the problems that this poses for making choices for the urban environment.     

平原河网地区河流曲度及城市化响应

河流曲度是河流平面形态的重要表征指标,以平原河网地区典型区域——上海为例,分析了20世纪50年代中心城区高密度河网的河流曲度特征,诊断了近60年以来快速城市化对区域河网及河流曲度的影响。研究认为:①近60年来上海中心城区河网密度下降幅度达67.22%,高强度人类活动导致区域河网水系分枝结构与自然规律完全相反;②平原河网地区是顺直型河流的典型发育区域,研究初期上海中心城区顺直型河流占85.40%,进一步分析表明曲度小于1.1的河流比例高达70.57%,河流形态接近于直线型;③上海中心城区消亡河流以顺直型为主,其消亡速率约为较高曲度河流的12倍,采用加权平均曲度指标描述区域河网萎缩对河流曲度的影响具有更好的直观性和科学性;④上海城市河流综合整治实践中,工程水利的倾向性强于生态水利,60.9%的河流整治项目开展了裁弯取直工程措施。     

The caranto paleosol and its role in the early urbanization of Venice

As rising sea level threatens Venice, there is a need to construct a historical framework for interpreting modern environmental changes. Environmental conditions that would later help support Venice's urbanization were established during the Late Glacial period when calcic soils began to develop in the Venetian alluvial paleoplain. A calcic paleosol, buried by Middle to Late Holocene marine transgressive deposits, represents a subsurface layer long known in the Venice area as “caranto.” Referenced in the ancient chronicles of architects and builders, the caranto exhibits relatively high compressive and shear strength, making it an important substrate for supporting building foundations, some dating back to the Gothic era (12th–15th centuries A.D.). Hence, the caranto paleosol documents local post‐glacial environmental changes while playing an important role in Venetian building construction and human settlement. Here we provide geochemical, sedimentological, paleoecological, and chronological analyses of the caranto paleosol and related deposits based on recent coring of the Venetian Lagoon. © 2011 Wiley Periodicals, Inc.     

Impact of urbanization on hydrological processes under different precipitation scenarios

Natural Hazards - According to analysing the trends of land use changes in the upper reaches of Minjiang River in the past 30 years and precipitation in the last 50 years, nine...     

Scale aspects of groundwater flow and transport systems

Flow-system analysis is based on the concept of hierarchical groundwater flow systems. The topography of the water table, which is strongly related to the topography of the land surface, is a major factor in the hierarchical nesting of gravity-driven groundwater flow, resulting in flow systems of different orders of magnitude in lateral extent and depth of penetration. The concept of flow systems is extremely useful in the analysis of spatial and temporal scales and their mutual relationships. Basic equations on the laboratory scale are extended to larger, regional scales. Making use of Fourier analysis further develops Tóth's original idea of topography-driven flow systems. In this way, the different spatial scales of the water table are separated in a natural way, leading to a simple expression for the penetration depth of a flow system. This decomposition leads also to the relationship between spatial and temporal scales. Analogous to flow systems, water bodies with different water quality may be called 'transport systems.' Field studies, numerical micro-scale modeling over macro-scale domains, and stochastic dispersion theory indicate that between systems with steady transport, the interfaces are relatively thin. The interfaces are much thinner than the relatively large mixing zones predicted by the conventional engineering approach to macrodispersion, in which relatively large, time-independent macrodispersion lengths are applied. A relatively simple alternative engineering approach is presented. For macrodispersion of propagating solute plumes, the alternative dispersion term gives the same results as the conventional engineering approach and gives correct results for steady-state transport.     

城市三维地质建模及其在城镇化建设中的应用

城市是建设在地质体之上的,这就注定城市的建设发展离不开地质工作的支撑。城市三维地质建模是三维信息技术在城市地质领域的一个典型应用,可大大提升城市地质调查成果的表达方式,提高城市地质资源环境的评价预测能力,对中国正在大力实施的城镇化建设具有重要支撑作用。对城市三维地质模型进行了分类,分析了城市三维地质模型的特点;研究了城市三维地质模型的构建,并对城市三维地质结构模型的构建进行了详细阐述;以北京市为例,给出了城市三维地质建模服务城市规划、地铁隧道选线施工、新城建设、重点工程选址、资源开发等方面的应用实例。     

城市三维地质建模及其在城镇化建设中的应用

城市是建设在地质体之上的,这就注定城市的建设发展离不开地质工作的支撑。城市三维地质建模是三维信息技术在城市地质领域的一个典型应用,可大大提升城市地质调查成果的表达方式,提高城市地质资源环境的评价预测能力,对中国正在大力实施的城镇化建设具有重要支撑作用。对城市三维地质模型进行了分类,分析了城市三维地质模型的特点;研究了城市三维地质模型的构建,并对城市三维地质结构模型的构建进行了详细阐述;以北京市为例,给出了城市三维地质建模服务城市规划、地铁隧道选线施工、新城建设、重点工程选址、资源开发等方面的应用实例。     

A comparative study of waste landfill disposal in different countries

This study draws attention to the fact that natural processes can mobilize thallium （Tl）, a highly toxic metal, which may enter the food chain with severe health impacts on the local human population. A rural area having independent Tl mineralization in southwestern Guizhou, China, was chosen for a pilot study. Tl contents of soils extracted by HNO3 in the study area range from 35-165 mg/kg in soils from the mining area, 14-78 mg/kg in alluvial deposits downstream, and 〈0.2-0.5 mg/kg in soils from the background area. Tl contents in ammonium acetate EDTA-extracted fraction are 0.013-1.3 mg/kg, less than 1% of concentration in HNO3-extracted fraction. The amounts of Tl in NH4Ac-extracted fraction were thought to be more exchangeable and bioavailable, i.e., immediately available to plants and/or available to plant roots over a period of years. Tl concentration in crops exhibits species-dependent preferences. The enrichment of Tl in edible crop species decreases in the following order： green cabbage〉chili〉Chinese cabbage〉rice〉com. The highest level of Tl in green cabbage is up to 500 mg/kg （DW）, surpassing the values of Tl in the soils （13-59 mg/kg）. The enrichment factor for TI in green cabbage is up to 1-10 when considering the HNO3-extracted Tl, but the factor highly rises to 30-1300 while considering the NH4Ac-extracted Tl. The average daily uptake of Tl by the local villagers through consumption of locally planted crops was estimated at about 1.9 mg per person, which is 50 times the daily ingestion from the Tl-free background area.     

The earthquake of March 4, 1977, its recording peculiarities and source parameters

A detailed analysis of recording peculiarities at seismic stations of the Uniform System of Seismic Observations (USSO) is presented a complicated nature of the source being shown. Consideration is given to parameters of the earthquake source, including the seismic moment and the length of the rupture.Comparison of magnitudes M_LH and M_PV indicates an anomalous attenuation in surface waves, itis is 3–4 times weaker than it had been noticed in case of other intermediate-depth Carpathian earthquakes.On the basis of comparison of the logarithm of the ratio of P-wave spectra at different epicentral distances (30° –70° ), the fac tor characterizing the absorption of P wave is found to remain practically unchanged.Average value of the seismic moment is estimated to be 2.6 × 10²⁷ dyne × cm, the most reasonable length of the rupture 58 km, and its focus 100 –130 km. The source parameters of the earthquake in question are compared with those of the earthquake of November 10, 1940.     

高度城镇化背景下水系演变及其响应

针对长江三角洲地区高度城镇化对水系剧烈影响的事实,以该区太湖平原苏州市为例,选取河网密度、水面率、分形维数和支流发育系数作为水系变化指标,运用GIS分析近50年来河网的时空变化规律,在此基础上,研究水系变化对于城镇化及降水变化的定量响应,分析高度城镇化下水系的发展趋势。结果表明:①近50年来研究区水系呈衰减趋势,河网密度、水面率、分形维数和支流发育系数分别下降5.6%、19%、1.2%和3%;区内水系禀赋差异大。②近50年来水系衰减的主要影响因素为城镇化,气候变化对其影响相对较弱;在水系变化中,城镇化的贡献率在67%以上。③随着城镇化率增加,研究区河网密度、分形维数、支流发育系数呈现先增长后衰减的"倒U型"曲线特征;苏州的高度城镇化与其水系表现出"先松弛,后紧密"的关系,二者的发展目前处于曲线右侧;未来将过渡到"高水平适应阶段"。本研究的结果丰富了城镇化与水系发展关系研究,可为其他地区水系系统的健康、绿色发展和保护提供参考。     

长三角地区人口城镇化空间差异及其影响因素研究

以长江三角洲41个城市市域为研究单元,基于2017年统计年鉴数据,构建影响因子体系,利用探索性空间数据分析和GWR模型,定量研究长三角市域人口城镇化空间差异、影响因子及其异质性作用。结果显示:长三角市域人口城镇化水平发展不平衡,存在明显的空间分异特征,呈现出以上海市为核心的梯度集聚分布;经济发展活力、投资强度、第一产业发展水平、医疗资源对于各市人口城镇化起着异质性作用,其中经济因子占主导作用、医疗资源因子的异质性作用显著。据此从推进一体化、高质量发展角度,为长三角人口城镇化协调发展提出建议。     

北方寒冷地区城市哈尔滨人口城市化与土地城市化协调关系研究

以哈尔滨市为研究范围,构建了人口城市化、土地城市化指标体系,运用熵值法计算各指标的权重,结合协调发展模型,分别研究了哈尔滨市1997-2014年期间人口城市化的内部协调性、土地城市化的内部协调性以及人口城市化和土地城市化的协调度及协调发展水平,并对人口城市化、土地城市化与协调发展水平进行了研究。结果表明：哈尔滨市的人口城市化内部协调性和土地城市化内部协调性都表现出前期加速,后期平稳的状态,在20世纪90年代,人口城市化内部协调性和土地城市化内部协调性都迅速提高,进入21世纪以后,协调度均保持在0.9左右,波动较小,内部协调度较高;综合人口城市化和土地城市化的协调度和相对发展度来看,除1999-2000年处于高级协调外,在研究期的其余时段哈尔滨市人口城市化和土地城市化基本处于初级协调状态,人口城市化与土地城市化的非同步性,是制约两者协调发展的关键因素,其中人口城市化对协调发展水平的影响更大。