Rapid Urbanization Area Research Articles

Urban expansion in Zanzibar City, Tanzania: Analyzing quantity, spatial patterns and effects of alternative planning approaches

Rapid urbanization and urban area expansion of sub-Saharan Africa are megatrends of the 21st century. Addressing environmental and social problems related to these megatrends requires faster and more efficient urban planning that is based on measured information of the expansion patterns. Urban growth prediction models (UGPMs) provide tools for generating such information by predicting future urban expansion patterns and allowing testing of alternative planning scenarios. We created an UGPM for Zanzibar City in Tanzania by measuring urban expansion in 2004–2009 and 2009–2013, linking the expansion to explanatory variables with a generalized additive model, measuring the accuracy of the created model, and projecting urban growth until 2030 with the business-as-usual and various alternative planning scenarios. Based on the results, the urban area of Zanzibar City expanded by 40% from 2004 to 2013. Spatial patterns of expansion were largely driven by the already existing building pattern and land-use constraints. The created model predicted future urban expansion moderately well and had an area under the curve value of 0.855 and a true skill statistic result of 0.568. Based on the business-as-usual scenario, the city will expand 89% from 2013 until 2030 and will continue to sprawl to new regions at the outskirts of the current built-up area. Establishing new urban centers had the highest impact on directing urban expansion from the tested alternative planning scenarios. However, the impact of all scenarios was low and therefore also other planning solutions such as vertical development, urban growth boundaries, and gradual improvement of the informal areas should be considered in Zanzibar.

Low Impact Development Intensive Rural Construction Planning in Xu Fu Village Ningbo, China: Planning Review through Rural Resilience Perspective

Xu Fu Village Ningbo LID Intensive Rural Construction Planning is a cooperation project between Zhejiang University and Ningbo Institute of Technology which named "12th Five-Year National Science and Technology support program-the comprehensive demonstration of the key technology of the beautiful rural construction in the rapid urbanization area of the Yangtze River Delta". This plan focuses on intensive rural construction as part of rural development and construction project that applies the principles of low impact development. Xu Fu Village located in the Yangtze River Delta Region. Currently, the rural growth brings the high impact of development, as a result of rapid urbanization growth arising several issues, such as low land use efficiency, dispersed rural residence, homestead occupies more, rural roads covering over, etc. Meanwhile, Xu Fu village wishes to develop its tourism potential. Thus, the intensive rural construction should be done to avoid the severe effect. The project result hopefully can improve the quality and level of rural residential planning, design, and construction; improve their living environment; save construction land and water use; and improve energy efficiency. The aim of this study is to review the Low Impact Development (LID) Intensive Rural Construction in Xu Fu Village, Ningbo City through the rural resilience perspective. This paper will describe the project plan first, then review it through rural resilience perspective. This paper will elaborate the rural resilience theory and then review the rural resiliency through two parts; the first part is identifying rural resilience in rural infrastructure development based on the criteria created by Ayyob S. and Yoshiki Y. (2014), about urban resiliency criteria, and then the second part is reviewing Xu Fu Village resilience through Arup Resilience Qualities (2012), considering three rural resilience domain (economy, ecology, and cultural).

Reprint of: Aggregate risk assessment of polycyclic aromatic hydrocarbons from dust in an urban human settlement environment

Due to the coal-dominated energy structure and increasing numbers of vehicles, gaseous polycyclic aromatic hydrocarbons (PAHs) emissions are increasing in many cities in China. These emissions have the potential to threaten human health, especially when aggregated in human settlement environments located in areas of rapid industrialization and urbanization. In this paper, an urban aggregating health risk assessment framework based on a multiple-pathways exposure model, dose–risk relationships and scenario analysis, using dust as an environmental medium is proposed and examined for future study. In a case study of Nanjing, several dust samples were collected from different functional areas and the aggregate risk of polycyclic aromatic hydrocarbons in each sampling unit was assessed. The results indicated that non-carcinogenic risk and carcinogenic risk in Nanjing are currently acceptable, but cannot be ignored in the long term. The carcinogenic risk in the west of Nanjing was relatively high, but still acceptable, while it was lower in central and southeast Nanjing and lowest in the northeast. These results can be further utilized for urban planning. Future urban construction in Nanjing, especially residential construction, should be expanded to the south of the city rather than the west, to minimize the human health risk caused by industries.

Exploring land-use legacy effects on taxonomic and functional diversity of woody plants in a rapidly urbanizing landscape

Urban vegetation is influenced by prior land use due to the dynamic nature of urban landscape. However, limited information is available on how strongly the land-use legacy impacts the diversity of urban vegetation, especially in areas of rapid urbanization. This study quantified the land-use legacy effect on taxonomic and functional diversity of woody plants in Haikou, China. We collected data on land use, percentages of woody vegetation cover, and abundance of woody plants from 461 randomly distributed sample plots. The influence of land-use legacy was examined by analyzing the land-use history of sample plots and taxonomic and functional α- and β-diversity of woody plants. The relative importance of the land use and the percentage of woody vegetation cover on the diversity of woody plants were analyzed using the boosted regression tree model. The result showed that the land-use legacy effect caused significant divergence in taxonomic and functional diversity of woody plants and the effect was most obvious in sites where the lands were currently used as residential areas. Remnant trees, shrubs, and possibly shrubs growing from seed banks and roots contributed to this legacy effect. We also found that taxonomic and functional α-diversities of trees in a site were influenced by how frequent the land use of the place was changed and what type of land use that the place ended up with. Based on our findings, we recommend conservation programs in rapidly urbanizing regions give more attention to vegetation in residential areas and particularly species with low utilitarian value.

快速城镇化地区土地利用及生态效率测算与分析

PDF HTML阅读 XML下载 导出引用 引用提醒 快速城镇化地区土地利用及生态效率测算与分析 DOI: 10.5846/stxb201610182126 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41501593，71225005）；中国博士后科学基金（2015M581163） Estimation and analysis of land use and ecological efficiency in rapid urbanization area Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:如何以较小的生态资源损耗获得较大的经济社会效益，是我国新型城镇化与生态文明建设关注的核心议题之一。以快速城镇化的湖北省为典型研究区，引入随机前沿分析（Stochastic Frontier Analysis，SFA）测度各县域的土地利用效率、生态绩效指数和生态效率。结果表明：（1）对比分析非约束模型与约束模型的检验结果可知，前者在本研究中有更好的解释能力，加入生态变量后县域土地利用效率平均值增加1.4%；（2）湖北省县域土地利用效率平均值为0.882，土地利用效率总体水平较高，且生态绩效指数（Ecological Performance Index，EPI）大于0的县域占75.73%，EPI随着土地利用效率（Land Use Efficiency，LUE）的增加表现出先增后减的倒U型变化；（3）湖北省县域的生态效率（Ecological Efficiency，EE）分布在0.778-0.989之间，空间格局特征明显，效率高值县域在空间上呈现出以武汉城市圈和沿长江、汉江为点轴的A型分布特征。本研究揭示了快速城镇化区域土地利用、生态系统和经济效益之间的关系，可为新型城镇化发展、土地资源高效利用和生态资源保护提供参考。 Abstract:One of the core issues of the new urbanization and ecological civilization construction is developing strategies for obtaining larger economic and social benefits with smaller ecological resource loss in China. In this study, Hubei Province, which has rapid urbanization, was considered a typical case area, and the stochastic frontier analysis (SFA) was used to measure the land use efficiency, ecological performance index, and ecological efficiency of each county in Hubei Province. The following results were obtained in this study. (1) We found that the non-constrained model had a better explanatory power than the constrained model did and the average land use efficiency increased by 1.4% after the addition of the ecological variable. (2) The average land use efficiency of Hubei Province was 0.882, whereas the overall land use efficiency was high and the counties with ecological performance indexes (EPIs) greater than 0 accounted for 75.73%. Furthermore, an increase in land use efficiency (LUE) resulted in EPI values showing inverted U-shape changes that first increased and then decreased. (3) The ecological efficiency (EE) of the counties of Hubei Province were between 0.778 and 0.989 and showed an obvious characteristic spatial pattern. In addition, the high-efficiency counties showed "A" type distribution characteristics that indicated the Wuhan metropolitan region was the point whereas the Yangtze River and Hanjiang River were on the axis. This study revealed that the relationship between land use, ecological system, and economic benefit in rapid urbanization area could provide a reference for new urbanization development, efficient utilization of land resources, and strategies for protecting ecological resources. 参考文献 相似文献 引证文献

Non-Point Source Pollutant Load Variation in Rapid Urbanization Areas by Remote Sensing, Gis and the L-THIA Model: A Case in Bao'an District, Shenzhen, China.

Urban sprawl is a major driving force that alters local and regional hydrology and increases non-point source pollution. Using the Bao'an District in Shenzhen, China, a typical rapid urbanization area, as the study area and land-use change maps from 1988 to 2014 that were obtained by remote sensing, the contributions of different land-use types to NPS pollutant production were assessed with a localized long-term hydrologic impact assessment (L-THIA) model. The results show that the non-point source pollution load changed significantly both in terms of magnitude and spatial distribution. The loads of chemical oxygen demand, total suspended substances, total nitrogen and total phosphorus were affected by the interactions between event mean concentration and the magnitude of changes in land-use acreages and the spatial distribution. From 1988 to 2014, the loads of chemical oxygen demand, suspended substances and total phosphorus showed clearly increasing trends with rates of 132.48 %, 32.52 % and 38.76 %, respectively, while the load of total nitrogen decreased by 71.52 %. The immigrant population ratio was selected as an indicator to represent the level of rapid urbanization and industrialization in the study area, and a comparison analysis of the indicator with the four non-point source loads demonstrated that the chemical oxygen demand, total phosphorus and total nitrogen loads are linearly related to the immigrant population ratio. The results provide useful information for environmental improvement and city management in the study area.

Countering decline of industrial sites: Do local economic development policies target the neediest places?

Local economic development is a much used tool for the regeneration of urban areas. Although the designation and effectiveness of local economic development policies has been studied extensively in existing literature, the question as to whether these policies are aimed at the areas that are most in need of these policies remains relatively understudied. This question has been answered using the case of industrial sites in the Netherlands. This particular type of urban area in the Netherlands has experienced problems with rapid urban area decline and has therefore been targeted by various area-based regeneration initiatives for many years. The economic performance is the main justification for the designation of industrial sites that are in greater need of regeneration. However, another pertinent and unanswered question is: are the industrial sites targeted for regeneration really the ones that underperform economically? (Multinomial) logistic regression analysis is used to answer this question. Differences in economic performance, measured by the growth in employment figures, the number of companies and property values, between industrial sites that are targeted for regeneration in two different rounds of regeneration initiatives and non-targeted sites are studied. The analysis shows that the differences in economic performance are negligible between these groups. It indicates that other criteria, such as political and strategic decision making influence policymakers’ decisions to target industrial sites for regeneration, thus making it at least doubtful that public money for the regeneration of industrial sites is being spent on what it is meant for.

Land Use/Cover Change from 2001 to 2010 and its Socioeconomic Determinants in Guangdong Province, A Rapid Urbanization Area of China

Rapid economic and population growth exert profound effects on land use/cover change, especially in rapid economically developing areas, such as Guangdong Province-a pioneer of economic growth and urbanization in China. To elucidate the changes and mutual conversions of land-use types and their determinants in Guangdong Province, land-use maps of Guangdong Province from 2001 to 2010 were obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) L1B images with 500 m resolution by using the supervised classification combined support vector machine (SVM) algorithm with a decision tree. The results indicate that during the studied time period, the area of urban land and orchards increased by 4186 km2 and 3615.5 km2, respectively, while the percentage of cropland decreased from 11.46% to 10.14%. Massive urbanization and cropland loss have occurred in the region. The conversion from wasteland to urban land, and the mutual transformation between wasteland and cropland were the most prevalent in Guangdong Province. This was especially obvious from 2007 to 2010, with an annual changing rate of 5.13% and -19.33%, respectively. Several socio-economic factors were also obtained to investigate their impacts on land-use changes in Guangdong Province. It is shown that marked increases in gross domestic product (GDP), total investment in fixed assets, total retail sales of consumer goods, and the increasing development of modern service industries have led to large-scale migration, and industrial structure adjustment and improvement; consequently dramatically rapid expansion of cities and cropland loss have occurred.

Aggregate risk assessment of polycyclic aromatic hydrocarbons from dust in an urban human settlement environment

Due to the coal-dominated energy structure and increasing numbers of vehicles, gaseous polycyclic aromatic hydrocarbons (PAHs) emissions are increasing in many cities in China. These emissions have the potential to threaten human health, especially when aggregated in human settlement environments located in areas of rapid industrialization and urbanization. In this paper, an urban aggregating health risk assessment framework based on a multiple-pathways exposure model, dose–risk relationships and scenario analysis, using dust as an environmental medium is proposed and examined for future study. In a case study of Nanjing, several dust samples were collected from different functional areas and the aggregate risk of polycyclic aromatic hydrocarbons in each sampling unit was assessed. The results indicated that non-carcinogenic risk and carcinogenic risk in Nanjing are currently acceptable, but cannot be ignored in the long term. The carcinogenic risk in the west of Nanjing was relatively high, but still acceptable, while it was lower in central and southeast Nanjing and lowest in the northeast. These results can be further utilized for urban planning. Future urban construction in Nanjing, especially residential construction, should be expanded to the south of the city rather than the west, to minimize the human health risk caused by industries.

Land use/cover change from 2001 to 2010 and its socioeconomic determinants in Guangdong Province, a rapid urbanization area of China

Rapid economic and population growth exert profound effects on land use/cover change, especially in rapid economically developing areas, such as Guangdong Province-a pioneer of economic growth and urbanization in China. To elucidate the changes and mutual conversions of land-use types and their determinants in Guangdong Province, land-use maps of Guangdong Province from 2001 to 2010 were obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) L1B images with 500 m resolution by using the supervised classification combined support vector machine (SVM) algorithm with a decision tree. The results indicate that during the studied time period, the area of urban land and orchards increased by 4186 km2 and 3615.5 km2, respectively, while the percentage of cropland decreased from 11.46% to 10.14%. Massive urbanization and cropland loss have occurred in the region. The conversion from wasteland to urban land, and the mutual transformation between wasteland and cropland were the most prevalent in Guangdong Province. This was especially obvious from 2007 to 2010, with an annual changing rate of 5.13% and -19.33%, respectively. Several socio-economic factors were also obtained to investigate their impacts on land-use changes in Guangdong Province. It is shown that marked increases in gross domestic product (GDP), total investment in fixed assets, total retail sales of consumer goods, and the increasing development of modern service industries have led to large-scale migration, and industrial structure adjustment and improvement; consequently dramatically rapid expansion of cities and cropland loss have occurred.

Spatial analysis of gastric cancer morbidity in regions of rapid urbanization: a case study in Xiamen, China

This paper is purposed to detect the spatial laws of gastric cancer in the rapid urbanization area and analyze relationships between gastric cancer and urbanization. Gastric cancer incidence data in Xiamen between 2006 and 2009 was collected from Xiamen CDC (Centre of Disease Control and Prevention). Urbanization age of Xiamen Island was calculated from remote images and terrain maps. Analysis results showed that 995 gastric cancer cases, accounting for 61.64 % was in Xiamen island, compared with 619 cases, accounting for 38.36 % outside. The average gastric cancer incidence was 32.98/1000,000 in Xiamen Island, compared to 16.13/1000,000 outside. The top ten sub-districts of gastric cancer all located in Xiamen Island, and urban areas have as more than twice gastric cancer incidence as rural area, with 28.62/100,000. The most likely spatial cluster of gastric cancer was Xiamen Island. Correlation analysis results indicated the urbanization age and spatial cluster degree had a significantly positive correlation relationship. Rapid urbanization in Xiamen changed the environment, namely acquired factors including land use change, air–water–soil pollution, less activity, electromagnetic radiation and contaminated sea foods. These are risk factors of gastric cancer. This research indicated that Xiamen Island was prevalent of gastric cancer with a positive correlation with urbanization age.

Heavy metals in soils and road dusts in the mining areas of Western Suzhou, China: a preliminary identification of contaminated sites

Purpose Contaminated sites will restrict regional development, especially the residential area development as the contamination can pose long-term adverse health risks. Western Suzhou, where three mining areas are located, is a rapid urbanization area in Suzhou City, Jiangsu Province, the People’s Republic of China. This urbanization has been pushing into the mining areas. This study aims to assess the heavy metal contamination (including Cu, Zn, Pb, Cd, Hg, Cr, As, and Ni) and identifies the contaminated sites in Western Suzhou.

A 30-year (1984–2013) record of annual urban dynamics of Beijing City derived from Landsat data

Although mapping activities of urban land change have been widely carried out, detailed information on urban development in time over rapid urbanization areas would have been lost in most studies with multi-year intervals. Here we provide a two-stage framework of long-term mapping of urban areas at an annual frequency in Beijing, China, over the period from 1984 to 2013. Classification for each year was carried out initially based on a number of Landsat scenes within that year using spectral information from a base image plus NDVI time series derived from all scenes. A temporal consistency check involving both temporal filtering and heuristic reasoning was then applied to the sequence of classified urban maps for further improvement. We assessed this time-series of urban maps based on two schemes. One is change detection in rapidly developing areas over the past three decades, and the other is accuracy assessment over the whole region in four selected years (i.e., 1984, 1990, 2000 and 2013). Based on validation using independent samples, the OAs (overall accuracies) of these four years are 96%, 93%, 92% and 95%, respectively. Meanwhile, the average accuracy of change detection for all years is 83%. In addition, the proposed temporal consistency check was found to be able to make considerable improvements (about 6%) to the overall accuracies and results of change detection. The resultant urban land sequence revealed that the average growth rates were 47.51±4.17km2/year, 34.65±2.90km2/year and 99.48±1.3km2/year for 1984–1990, 1990–2000 and 2000–2013, respectively.

A Coupled SD and CLUE-S Model for Exploring the Impact of Land Use Change on Ecosystem Service Value: A Case Study in Baoshan District, Shanghai, China.

Most of the cities in developing countries are experiencing rapid urbanization. Land use change driven by urban sprawl, population growth, and intensified socio-economic activities have led to a steep decline of ecosystem service value (ESV) in rapid urbanization areas, and decision-makers often ignore some valuable ecosystem service functions and values in land use planning. In this paper, we attempt to build a modeling framework which integrated System Dynamics model with Conversion of Land Use and its Effects at Small Extent model to simulate the dynamics of ESV of landscape and explore the potential impacts of land use change on ESV. We take Baoshan district of Shanghai as an example which is a fast urbanization area of metropolitan in China. The results of the study indicate that: (1) The integrated methodology can improve the characterization and presentation of the dynamics of ESV, which may give insight into understanding the possible impacts of land use change on ESV and provide information for land use planning. (2) Land use polices can affect the magnitude and location of ESV both directly and indirectly. Land use changes tend to weaken and simplify ecosystem service functions and values of landscape at urban rural fringe where land use change is more intensive. (3) The application of the methodology has proved that the integration of currently existing models within a single modeling framework could be a beneficial exploration, and should be encouraged and enhanced in the future research on the changing dynamics of ESV due to the complexity of ecosystem services and land use system.

东莞市人工景观结构与连接度的协整性及因果关系

PDF HTML阅读 XML下载 导出引用 引用提醒 东莞市人工景观结构与连接度的协整性及因果关系 DOI: 10.5846/stxb201311052673 作者: 作者单位: 广州大学地理科学学院,广州大学地理科学学院,广州大学地理科学学院,广州大学地理科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家科技支撑计划课题(2012BAH32B03);国家自然科学基金项目(41071078);教育部人文社科规划基金项目(11YJAZH016);住房和城乡建设部科学技术项目(2012-K8-42)资助 Research on the cointegration and causality between urban artificial landscape structure change and landscape connectivity in Dongguan City Author: Affiliation: School of Geographical Sciences,Guangzhou University,School of Geographical Sciences,Guangzhou University,School of Geographical Sciences,Guangzhou University,School of Geographical Sciences,Guangzhou University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:城市人工景观特征逐步向城市外围自然及半自然景观渗透。近年来对快速城市化地区的景观格局特征定量化研究很多,但侧重于景观格局特征的简单分析和描述,忽略了城市空间扩展过程中,城市人工景观结构与景观连接度动态变化过程中之间的内部联系。以东莞市1988-2009年城市人工景观为研究对象,通过计算并分析景观结构与景观连接度指数,利用计量经济学中的协整概念与格兰杰因果检验方法并详细分析了这两类指数之间的具体关系。研究结果表明:(1)所选取的景观结构指数与景观连接度指数能较好地描述东莞市城市人工景观时空格局变化过程;(2)人工景观斑块类型面积(CA)与可能连通性指数(PC)存在协整关系。景观聚集度指数(AI)、蔓延度指数(CONTAG)与景观连通性指数(IIC与PC)也存在协整关系,即这些变量之间确实存在长期均衡关系;(3)格兰杰因果关系检验中,在不同滞后期的情况下,大部分的结果表明景观连接度指数(IIC与PC)是景观结构指数(CA、AI、CONTAG)的格兰杰成因,说明景观连接度指数信息有助于预测景观结构指数的变化。 Abstract:Characteristics of urban artificial landscape have permeated into natural and semi-natural landscapes. Prior studies focused on landscape pattern analysis and description in rapid urbanization areas but neglect the dynamic changes between structures and connectivity of artificial urban landscape and their internal interactions. We measured two landscape indices (landscape structures and landscape connectivity) and presented an integrated approach (the cointegration and causality) to explore the urban expansion of Dongguan, a rapidly growing city in southern China, since 1988 to 2009. Analyses of seven landscape indices indicates a clear dynamic change in the expansion of Donguan. We divided this expansion into four different periods, that is early natural and semi-natural landscapes dominated urban areas in 1988-1990, followed by rapid 'extension' and 'linear development' period through 1990-1999, and then urbanization developed steadily period ('sprawl') during 1999-2005, and the recent 'infilling' stage since 2005-2009 characterized by urban development? The results show that: (1) According to variation characteristics of seven indices, the period is divided into four stages. The first is 1988-1990, in which the natural and semi-natural landscapes such as farmland, woodland were dominant, while urban artificial areas were small and had low density and aggregation. The second period is 1990-1999, in which urban artificial landscape increased rapidly with high density and aggregation. Then, we named the urban land expansion as 'extension' and 'linear development' type. The skeleton of the city gradually formed and the urban artificial landscape was in the dominant position, while natural and semi-natural landscapes such as farmland, woodland were small with low density and aggregation. The third period is 1999-2005. The total area of urban artificial landscape grew steadily and we named the urban land expansion as 'sprawl' type. The last is 2005-2009. Urban artificial landscape grew further and we named the urban land expansion as 'infilling' type. (2) There exist cointegration relationships between class area (CA) and probability index of connectivity (PC), aggregation index (AI), contagion index (CONTAG), and connectivity indices IIC and PC. This indicates that there is a long-term equilibrium relationship among these variables and thereby no internal mechanism would break down the equilibrium of urban system. (3) Granger causality test shows that landscape connectivity indices (IIC and PC) are the Granger Causes of landscape structure indices (CA, AI, CONTAG), which suggests the landscape connectivity indices can be used to predict the change of landscape structures. 参考文献 相似文献 引证文献

Environmental Policy Simulation and Assessment under Rapid Urbanization: Case Study of Essential Area Policy in Shenzhen, China

AbstractThe balance between overall economic growth and protection of the environment is an important research topic of urban sustainable development. In 2005, Shenzhen promulgated the regulations, Administrative Regulations of Shenzhen Municipality on the Essential Area for Protecting Ecology [abbreviated as essential area policy (EAP)], which limited development to protect ecology. In order to evaluate the effects of this policy, a computer model was used to simulate land-use change based on a land-use change survey dataset of Shenzhen, a typical rapid urbanization area, under four scenarios. The writers aimed at developing a clear understanding of not only the effects of land protection policies for urban ecosystems but of a well-grounded prospect for regionally coordinated development as well. Five landscape structure metrics were chosen to describe the landscape pattern, including (1) number of patches, (2) mean patch area, (3) landscape shape index, (4) aggregation index, and (5) contagion index. In...

Monitoring the land subsidence with persistent scatterer interferometry in Nansha District, Guangdong, China

Nansha District in Guangzhou, south China, as a well-known rapid urbanization area, is characterized by the widely distributed soft soil prone to land subsidence. Accurate monitoring of surface deformation plays a significant role for the hazard prevention and mitigation. In this study, 21 high-resolution TerraSAR-X satellite images acquired from February 2012 to August 2013 are processed with the persistent scatterer interferometry (PSI) technology to detect and reveal the land subsiding characteristics of Nansha District. Based on the comparisons among the PSI, the GPS measurements, and the civil construction process, the land subsiding characteristics are discussed. The difference between PSI and GPS velocity rates on the line of sight direction is less than 3.61 mm/year, showing fairly consistent agreement. Meanwhile, the PSI results show that the Nansha Automobile Industrial Area, Tongxin Industrial Area, Xinan Industrial Area, Nanheng, and Dugang of Sanjiao town in Zhongshan City were stable, where the subsidence velocities were less than −5 mm/year. The moderate subsidence, whose velocities ranged from −20 to −5 mm/year, mainly occured in the Dayuancun village and Gaoping village of Sanjiao town in Zhongshan City. The severely subsiding areas, where the velocities are more than −20 mm/year, were detected in Nansha Export Processing Zone and Minzhong town in Zhongshan City. For the primary roads and bridges, the newly built bridges, such as Hengli Flyover and southern side of Fuzhou Bridges, were suffering a subsidence velocity from −10 to −15 mm/year. On the contrary, the old roads and bridges turned out to be stable, for instance, the Nanshagang Expressway, Hongqili and Lixinsha Bridges. The civil engineering documents and other related materials show that most of the subsidence took place within the rational post-construction period. However, the subsidence in and around self-constructed substandard houses in the countryside are rather severe due to the lack of sufficient soft soil foundation treatment.

基于增强回归树和Logistic回归的城市扩展驱动力分析

PDF HTML阅读 XML下载 导出引用 引用提醒 基于增强回归树和Logistic回归的城市扩展驱动力分析 DOI: 10.5846/stxb201212121790 作者: 作者单位: 中科院沈阳应用生态研究所，森林与土壤生态国家重点实验室,中科院沈阳应用生态研究所，森林与土壤生态国家重点实验室,中科院沈阳应用生态研究所,中科院沈阳应用生态研究所，森林与土壤生态国家重点实验室,中科院沈阳应用生态研究所，森林与土壤生态国家重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目（41171155）；国家科技支撑计划课题资助项目（2012BAJ15B06） Driving forces analysis of urban expansion based on boosted regression trees and Logistic regression Author: Affiliation: State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences,State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences,Chinese Academy of Sciences, Shenyang Liaoning,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:研究城市扩展驱动力对于准确判断城市发展规律，剖析演化过程和预测城市未来扩展趋势具有重要意义，同时也能为制定合理的调控政策提供指导。以沈阳市1997-2010年城市建成区变化作为因变量，选取三大类10种驱动因子，利用增强回归树（BRT）和Logistic回归两种方法分析影响城市扩展的主要驱动力。结果表明：（1）BRT分析得到影响沈阳城市扩展的驱动因子从大到小依次是：距1997年城区距离、距河流距离、数字高程模型DEM、距高速公路和铁路距离、土地利用类型、开发区规划、GDP、人口密度、坡向和坡度；（2）Logistic回归分析得到影响沈阳城市扩展的前8位驱动因子依次是：开发区、距1997年城区距离、DEM、距高速公路和铁路距离、人口密度、距河流距离、农村居民点和坡度；（3）距1997年城区距离、DEM、距高速公路和铁路距离是影响沈阳城市扩展的主要驱动力，均位于主要因子的前四位；（4）总体来说，沈阳城市扩展受邻域因子影响最大，而自然因子的影响相对较小，社会经济因子则只有开发区和农村居民点对城市扩展影响较大。 Abstract:The rapid relentless urban area expansion has led to a series of problems in China. Many researches focused on this issue in recent years. Driving forces are the core topic in urban expansion,as well as the basic component of modeling and predicting. It is very useful and meaningful to analyze the driving force of urban expansion, which may provide us with a scientific basis to rationally utilize land resources, determining the law of urban development, researching the evolution process, predicting the urban expansion trends, and also providing guidance for the development of rational control policies.The Shenyang city was chosen as study area. Eight categories of land use types were extracted from remote sensing images (1997 and 2010) with ArcGIS software. Ten driving forces were chosen, including three natural factors, three distance factors, four social and economic factors. which were calculated based on the land use maps, DEM, topographic maps, zoning maps and the statistical yearbooks. The dependent variable was the change of built-up area of Shenyang from 1997 to 2010. Boosted regression trees (BRT) is an ensemble method and is a combination of techniques between statistical and machine learning traditions that has shown to be effective to identify relationships between results and influencing factors. Logistic regression is a method to discover the empirical relationships between a binary dependent and several independent categorical and continuous variables. Boosted Regression Trees and Logistic regression were used to analyze the main driving force of urban expansion synthetically.The result illustrated the relative influence of driving factors was followed by distance from urban area of 1997, distance from river, DEM, distance from highway and railway, land use types, development plan, GDP, population density, aspect, and slope based on BRT analysis. According to Logistic regression analysis, the relative influence of important factors was followed by development zone, distance from urban land of 1997, DEM, distance from highway and railway, population density, distance from river, rural residential areas and slope. The most important driving forces affecting the expansion of Shenyang are distance from urban area of 1997, DEM, distance from highway and railway. Meanwhile, they were all located in the top four of the main factors. The results revealed that the distance factors were the most important factors, and the total contribution rate of relative influence was up to 61.4%. It is demonstrated distance factors are the main driving forces of urban expansion. Natural factorswere less important, but the relative influence of DEM was important, and the contribution rate was 12.5%. Development zones and rural settlements are the only two factors have much influence in the socio-economic factors.On the whole, location factors, which refer to the distance from urban land in this study, were the leading factors of urban expansion. Natural factors, such as DEM, rivers and so on, are the basis of urban development, determining the overall urban spatial form. The construction of infrastructures, such as roads and railways, are the frame of the city. The social and economic factors decided the speed of urban expansion. Urban planning and development zone construction provided the direction of urban expansion. 参考文献 相似文献 引证文献

Study on Community Residential Space with Block Unit Mixed Community Theory in Rapid Urbanization Region: Taking Xi'an Changning Newtown Community Planning as an Example

The community planning of rapid urbanization area is a problem worth studying under the background of the urbanization at present. To explore the problem of the community existence during Chinese rapid urbanization, and to search for rational approaches to planning and design of community living space of rapid urbanization area are the main goal of this thesis. On the basis of the issues and characteristics of rapid urbanization area community and by analyzing the analogy, a set of method is summarized by the theory of block unit mixed community relying on the case studies.

Spatial pattern of heavy metal concentration in the soil of rapid urbanization area: a case of Ehu Town, Wuxi City, Eastern China

Urbanization has an important effect on the soil ecosystem. Anthropogenic activities during urban sprawl are the sources and methods of migration, transition, and concentration of heavy metals in the soil. In this paper, the Yangtze River delta, the fastest urbanization area in China, was selected to study the influence of urbanization on heavy metal concentration in the soil. The analysis was performed on 218 samples collected from a typical industrial town in the delta. The content of six heavy metals (Hg, Cd, As, Pb, Cu, and Zn) was measured, which showed that the soil was seriously polluted by heavy metals, particularly Hg. In the study area, human activities were the major factors for the heavy metal concentration in the soil. The average content of Hg in the 0–500 m zone from the urban core was 1.4 mg/kg, about five times higher than the grade II threshold of the Chinese Environmental Quality Standard for Soils. The content of Hg, Cd, Pb, and Cu decreased gradually with increasing distance from the core of the built-up area, especially Hg. The influence of the anthropogenic activities was found to be anisotropic, and effects in the direction of 315° and 225° were most significant. Hg pollution in the 225° direction of the study area was more serious. These results suggested that the urbanization process affects not only the content but also the spatial pattern of heavy metal concentration in the soil.