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1.
In the study of new towns and cities, spatial assimilation and the complex nature of urban development hold issues of special importance. At present, in developing countries like India, rapid development as well as urbanization in medium sized cities is a noticeable phenomenon. However,researchers in the field of urban study,lay emphasis on larger cities in our country. Therefore,more studies are essential to identify the problem and future prospect and also to suggest satisfactory policies for the betterment of medium sized cities.The current paper assesses the spatial expansion of the Siliguri (a fast growing medium sized city of Eastern India) designed for the year 1990, 2000, 2010 as well as 2019 using satellite imagery and field investigation.The research quantifies the urban growth and sprawling pattern in the study area using statistical techniques and spatial matrices.The other objectives of this study are to predict and analyze the urban growth of Siliguri Urban Agglomeration (UA) of 2030 with the help of a Future Land Use Simulation (FLUS) model. This simulation model was chosen by using a technique to evaluate the classified images in three maps: a time 1 reference map, a time 2 reference map and a simulation map of time 3. Spatial metrics and Shannon entropy results revealed that Siliguri (UA) is experiencing rapid sprawl. In contrast, the degree of freedom results revealed a significant gulf between the observed and planned urban development.The simulation model also showed that the unsustainable trend will likely to remain intact in the future, with the built-up area rising to 78.496 km2 by 2030, potentially resulting in loss of major cultivated land, fallow land and flora.
相似文献2.
S. Karbassi M. Malek T. Shahriari M. A. Zahed 《International Journal of Environmental Science and Technology》2016,13(12):2847-2854
In the present study, bulk contents of Ni, Zn, Cu, Pb and Mn in urban area of Tehran city are determined. Subsequently, the chemical bonds of metals with various soil fractions are brought out. Chemical partitioning studies revealed that various percentile of Ni, Zn, Cu, Pb and Mn is found in anthropogenic portion of soils. Zinc, Ni, Cu, Pb and Mn fall within “low pollution” class in accordance with index of pollution (I POLL). The trend of anthropogenic share of studied metals in soils of Tehran is Zn (55 %) > Cu (31 %) > Ni and Pb (30 %) > Mn (12 %). The overall potential of studied plants in metal removal from soil is Salvia > Viola > Portulaca. It should be pointed out that roots have higher potential in metal removal from soil when compared with leaf and stem. Lithogenic portion of metals remains intact before and after pot analysis. Thus, phytoremediation is highly dependent on the chemical bonds of metals. Present study showed that metal contents of loosely bonded ions, sulfide bonds and organometallic bonds are reduced after 90 days of plant cultivation. The overall removal trend of studied metals is Zn (16 %) > Cu (14 %) > Ni (11 %) > Pb (7 %) > Mn (6 %). The obtained results show that the anthropogenic portion of metals is reduced after the phytoremediation practice. For instance, the initial anthropogenic portion of Zn (55 %) is changed to 39 % showing an overall reduction of about 16 %. The anthropogenic portions of Cu, Ni, Pb and Mn are also reduced by 14, 11, 7 and 6 %, respectively. 相似文献
3.
《地学前缘(英文版)》2022,13(4):101385
Accurate modeling of urban climate is essential to predict potential environmental risks in cities. Urban datasets, such as urban land use and urban canopy parameters (UCPs), are key input data for urban climate models and largely affect their performance. However, access to reliable urban datasets is a challenge, especially in fast urbanizing countries. In this study, we developed a high-resolution national urban dataset in China (NUDC) for the WRF/urban modeling system and evaluated its effect on urban climate modeling. Specifically, an optimization method based on building morphology was proposed to classify urban land use types. The key UCPs, including building height and width, street width, surface imperviousness, and anthropogenic heat flux, were calculated for both single-layer Urban Canopy Model (UCM) and multiple-layer Building Energy Parameterization (BEP). The results show that the derived morphological-based urban land use classification could better reflect the urban characteristics, compared to the socioeconomic-function-based classification. The UCPs varied largely in spatial within and across the cities. The integration of the developed urban land use and UCPs datasets significantly improved the representation of urban canopy characteristics, contributing to a more accurate modeling of near-surface air temperature, humidity, and wind in urban areas. The UCM performed better in the modeling of air temperature and humidity, while the BEP performed better in the modeling of wind speed. The newly developed NUDC can advance the study of urban climate and improve the prediction of potential urban environmental risks in China. 相似文献
4.
The regionalization of urban natural disasters in China 总被引：1，自引：1，他引：0
Jing-ai Wang Pei-jun Shi Xiang-sheng Yi Hui-cong Jia Lai-yin Zhu 《Natural Hazards》2008,44(2):169-179
An integrated urbanization level (CL) index and an integrated natural disaster intensity (QC) index were developed on the
basis of Disaster System Theory and China Natural Disaster Database for integrated urban disaster risk assessment. Integrated
quantitative assessments of the urban socio-economic system and the intensity of hazards in China were carried out by the
Model-Tupu (map series) and inter-feedback process using digital map technology. On the basis of this assessment, China can
be regionalized into three regions, namely, coastal urban disaster region, eastern urban disaster region and western urban
disaster region, 15 sub-regions and 22 units. These results can provide a scientific basis for determining a city’s disaster
risk management and natural disaster relief regionalization in China.
相似文献
| Pei-jun ShiEmail: |
5.
Urban floods are sudden phenomena normally characterized by short flooding durations and devastating effects due to the high concentrations of persons, goods, and properties located in urban areas. In these cases, uncontrolled runoff can flow on urban streets, creating a significant hazard for pedestrians and vehicles. The safety of people can be compromised when they are exposed to flows that exceed their ability to remain standing or to traverse flow paths. With the aim of studying the stability of pedestrians in flooded street during storm events, a model representing an urban street in real scale was designed and built. Following a specific protocol that considering several flow rates (up to 500 l/s) and different longitudinal slopes (up to 10 %), 834 tests, using 23 human subjects, were carried out in good and poor light conditions. Hazard conditions were classified into three groups (low, medium, and high), and the parameters for which these conditions occurred were recorded. Results showed that for subjects weighing 50–60 daN (50–60 kg mass) and flow depths between 9 and 16 cm, velocities of 1.5–2 m/s can generate loss of stability due to phenomena of dragging or overturning. Empirical expressions were proposed to relate human subject characteristics (weight and height) and limiting flow conditions at which loss of stability occurs. 相似文献
6.
Urban geochemistry is a unique discipline that is distinguished from general geochemistry by the complex infrastructure and intense human activities associated with concentrated population centers. As stated by Thornton (1991) “This subject is concerned with the complex interactions and relationships between chemical elements and their compounds in the urban environment, the influence of past and present human and industrial activities on these, and the impacts or effects of geochemical parameters in urban areas on plant, animal and human health.” Urban areas present special challenges to geochemists attempting to understand geochemical states and fluxes. On the 5–6 of August, 2014, the first meeting of the reorganized Urban Geochemistry Working Group of the International Association of GeoChemistry (IAGC) was held in Columbus, Ohio, United States. Two goals of the meeting were to develop the overall scope, and a general definition of urban geochemistry. Five grand themes were developed: 1) recognizing the urban geochemical signature; 2) recognizing the legacy of altered hydrologic and geochemical cycles in urban environments; 3) measuring the urban geochemical signature; 4) understanding the urban influence on geochemical cycles from the continuous development and erosion of physical infrastructure and episodic perturbations; and 5) relating urban geochemistry to human and environmental health and policy. After synthesizing the discussion of these themes we offer the following perspective on the science of urban geochemistry building on the work of Thornton (1991): Urban geochemistry as a scientific discipline provides valuable information on the chemical composition of environments that support large populations and are critical to human health and well-being. Research into urban geochemistry seeks to 1) elucidate and quantify the sources, transport, transformations, and fate of chemicals in the urban environment, 2) recognize the spatial and temporal (including legacies) variability in these processes, and 3) integrate urban studies into global perspectives on climate change, biogeochemical cycles, and human and ecosystem health. We hope that this discussion will encourage other geochemists to engage in challenges unique to urban systems, as well as provide a framework for the future of urban geochemistry research. 相似文献
7.
The purpose of the study reported here is to assess whether it may in some circumstances be useful and appropriate to use a parent material (PM) soil chemistry mapping method developed for national soil chemistry data to portray spatial variation in urban soil chemistry data in Great Britain. Analysis of variance (ANOVA) of the urban soil data suggests that spatial interpolation of soil ambient background concentrations (ABCs) using PM classified soil data may be justified for those elements with strong geogenic control. The PM soil chemistry mapping method for urban soil data is demonstrated using data from the Northampton urban area, in the English Midlands. Geometric mean (GM) and inverse distance weighting (IDW) interpolations based on the nearest four topsoil samples were evaluated. Independent validation indicated that for As, Cr, Fe and to a lesser extent K, which all exhibit relatively strong geogenic control in the Northampton urban area: (i) the PM soil chemistry mapping method is more accurate and effective than the conventional IDW grid mapping and (ii) PM soil chemistry mapping based on the average of the nearest four Lne element concentrations is more accurate than mapping based on IDW values calculated from the nearest four Lne element concentrations. The variation in effectiveness of the methods can be explained by the fact that PM exerts a significant control on As, Cr, Fe and K in the Northampton area whereas anthropogenic inputs appear to be the dominant control on the spatial variation of Pb, especially at high concentrations. The PM mapping method would be expected to work efficiently in other urban areas and for those elements where a significant proportion of the variation can be explained by PM. 相似文献
8.
为研究城市小型河流中污染物的物理迁移过程规律,分析基流条件下流动水体与暂态存储区之间的滞留交互作用,采用溴化锂(LiBr)作为保守性示踪剂进行野外现场示踪试验,结合一维溶质运移存储模型(One-dimensional Transport with Inflow and Storage model, OTIS)定量解析潜流交换特性,估算纵向弥散系数(D)、潜流交换面积(As)、主河道断面面积(A)和潜流交换系数(α).模型度量指标DaI值和均方根误差值结果表征参数模拟结果可靠性高,拟合效果理想.由泵入点O至下游1 300 m设置的A、B、C、D 4处监测点的模拟结果表明,水文参数D、As、A和α均随水文条件而变,OB河段(0~600 m)潜流交换能力较弱,主要以对流弥散过程为主;BD河段(600~1 300 m)具有较强的暂态存储能力,对溶质的滞留时间长;BC(600~1 000 m)和CD(1 000~1 300 m)河段交换系数分别为(3.42×10-6±0.65×10-6)s-1和(2.87×10-6±0.81×10-6 )s-1;河段BC存在2.2×10-5m3/(s·m)的侧向补给流量.4个河段对比发现,城市河流渠道化、河床沉积物贫瘠等特征导致潜流交换能力弱化. 相似文献
9.
Bolivia is a country with high levels of poverty and inequality among its peoples and regions. For the nation and its urban
and rural areas, trends in the social and spatial distribution of poverty (and extreme poverty) are identified from 1976 to
2003 using UBN data with minor support where appropriate from poverty lines. The main survey between 1992 and 2001 uses composite
and selected UBN to track detailed poverty change for the country’s nine departments, its ten largest cities and a selection
of other smaller urban and rural municipalities. Because of rising background increases in population in the various surveyed
administrative units, many instances of relative reductions in poverty are accompanied by rising absolute increases. Marked
spatial variations in poverty and development in the country over the last several decades are identified as the main driver
for the country’s quickening pace of rural–urban migration. As a result, the paper concludes by assessing two different but
closely related views. One investigation tests the notion that because more poor people have been living in Bolivia’s cities
than in its rural areas since the mid to late 1990s, rapid rural–urban migration has simply shifted the locus of poverty from
the countryside to the cities in a process called, the ‘urbanisation of poverty.’ A second, more challenging, investigation
assesses the view that the flow of poor rural people to the better serviced urban areas of Bolivia has actually acted to alleviate
national poverty levels. 相似文献
10.
Defining the urban 总被引：1，自引：0，他引：1
A. Sayer Dr. 《GeoJournal》1984,9(3):279-284
In everyday discourse, the term urban causes few problems, but it certainly has for social theory. While the paper accepts the recent consensus that the term no longer serves to refer to a distinct object in capatalist societies, it argues that the familiar arguments have been confused by inadequate approaches to the problem of definition and inadequate concepts of space and ideology. Clarification of such definitions is a prime task of social theory and different methods of definition are discussed. The paper ends with a commentary on what is probably the best attempt at defining the urban — Raymond Williams The Country and the City. 相似文献
11.
IJ Van der Merwe 《GeoJournal》1993,31(4):409-417
In the changing South Africa of the nineties language planning becomes a top priority on the agenda of constitutional reform. It appears however, that some misplaced enthusiasm is generated by language planners regarding the relatively well defined language regions on a national level. It should be kept in mind that approximately two-thirds of the South African population presently resides in high density urban areas. Contrary to the relatively clear-cut regionalization implied by the rural language patterns, a different form of regional demarcation and language planning is necessary in large metropolitan areas where the population concentrations are the result of a multilingual migration process. Cape Town is a suitable experimental ground to focus the methodological and conceptual shift from a national to an urban resolution level in language mapping. The aim of this paper is to address the following issues: The generalconceptual niche of cities in geolinguistics; the spatial identification ofpresent language distribution in Cape Town; the time-space pattern oflanguage change in Cape Town; the socialprofile of language speakers in Cape Town; and the consequences of the findings forlanguage planning in Cape Town and South Africa. Although Cape Town is linguistically probably one of the least diverse cities in South Africa, three language groups (Africaans, English and Xhosa) are clearly apparent within the limited surface area of the urban space. Their respective distribution patterns are relatively segregated within specific neighbourhoods of the city. 相似文献
12.
Claudio 《Geoforum》2001,32(4)
This paper describes key urban development strategies pursued during the last seven years by the Municipality of Rio de Janeiro, the second largest city in Brazil. It discloses internal processes, organisational restructuring of the municipality and institutional changes geared to increase effective urban management and resource mobilisation required to implement multiple sector programmes and key projects in several locations in the city like Favela Bairro and Rio Cidade Programmes, The Rio Strategic Plan, etc. It is argued that the formation of interdepartmental working groups for better horizontal articulation of policy making and implementation, the creation of the financial and accounting unit, the decentralisation of authority towards sub-municipality levels, and capacity strengthening of its personnel – among other things – have made a positive impact on the performance of local government. The paper further highlights a significant change towards policies of urban consolidation and revitalisation of declined areas of the city supported by heavy public investments and the effort towards broader civil society involvement in municipal projects. Municipal autonomy, problem-solving and result-oriented type of planning and management and organisational change are some of the lessons pinpointed by the paper for a city of that size and complexity. 相似文献
13.
By comparing simultaneously observed data of humidity and precipitation in Shanghai Urban area with those in its suburbs, we first deal with the urban influences on humidity. We find that both the average absolute humidity and relative humidity (diurnal, monthly and annual) are lower in the city than those in the surrounding 10 counties but night-time absolute humidity excess in the city exhibits a moisture island similar to that of temperature. The example is shown from a summer night at 5 h on Aug. 10, 1959.When 20-year's records of isohyets of annual average precipitation, average precipitation of rainy seasons (May–September), and that of other seasons (October–April) are analyzed, the urban influences on the distribution of annual precipitation and the rainy season precipitation become obvious, but it seems that the other seasons are not affected.Some rain events that illustrate the main contributing causes are also discussed, namely, heat island, obstacle effects and pollution products, for the modification and augmentation of precipitation in urban area and in the lee of the city. 相似文献
14.
15.
A. Siddique S. Saied E. Zahir Z. A. Nayyer N. A. Zaigham 《International Journal of Environmental Science and Technology》2014,11(3):739-746
Trihalomethanes (THMs) are the most abundant disinfection byproducts (DBPs) of the chlorination disinfection. THMs speciation and their geospatial distribution were examined in 58 locations throughout the water distribution network of Karachi city. THMs (CHCl3, CHCl2Br, CHClBr2 and CHBr3) and physico-chemical parameters (pH, TDS, DO, Residual chlorine, temperature and TOC) were determined. CHCl3 was the major THM found in all water samples of 58 locations, which accounted for 91.69 % of the total THMS followed by CHCl2Br (5.69 %), CHClBr2 (1.78 %) and CHBr3 (0.85 %). Total THMs level exceed the maximum contamination level of WHO and USEPA at some locations. Varying nature of correlation from high to low was found within THMs and among the physico-chemical parameters. GIS linked geospatial analysis revealed the association of THMs level with demographical and geological based variations from east to west of Karachi city. Continuous monitoring program and legislation for the contaminant levels were suggested to avoid adverse public health impact of THMs in drinking water supplies. 相似文献
16.
Kaibarta Samyakami Mandal Somnath Mandal Pintu Bhattacharya Subhasis Paul Suman 《GeoJournal》2022,87(4):527-549
Poverty is the most important metric for determining the nature and sense of wellbeing in a given area. Most economists consider poverty to be an economic criterion for assessing many aspects of human development as well as overall social development; yet, society is multi-faceted in its many forms. To address this pressing societal issue, the current study used the Multidimensional poverty index (MPI). To analyse urban poverty among slum communities, the researchers used the Global MPI of the Oxford Poverty and Human Development Initiative and UNDP (following Alkire and Foster) techniques. Researchers attempted to create a Multidimensional poverty index (MPI) for impoverished households in Purulia's designated slums in this study. In the second phase, the multidimensional poverty of Purulia's urban poor households was assessed based on (a) location, (b) social groupings, and (c) length of stay. Finally, researchers have attempted to identify the factors that contribute to multidimensional poverty. Two indicators, the Head Count Ratio (H) and Intensity of Poverty, have been offered to better explain the nature of MPI (A). Based on slum population density and areal density, eight urban slum areas with 320 households has been taken from 8 selected slums based on Yamane’s methodology from Purulia Municipality's wards. A structured questionnaire, an oral history interview, and a focus group discussion were used as primary data sources, with secondary data acquired from several officially published sources. The study displays a decomposed multidimensional poverty picture in terms of overall condition, socioeconomic groups, and household age, with a quantitative methodology that is transparent. When the locations have been considered, a qualitative approach has been used to determine that the slums closest to the railway track are the most multidimensionally disadvantaged of the eight slums. Furthermore, the schedule caste population has been found to be more deprived across many socioeconomic groups, with Scheduled tribe (ST) households being the most deprived in terms of health on one hand (applied quantitative methodology) and multi-nominal regression (applied qualitative methodology) indicating a mix mode approach. This form of analysis, which combines quantitative and qualitative approaches, can aid stakeholders and policymakers in developing specific poverty-reduction policies at the regional level.
相似文献17.
国内外城市环境地质工作进展 总被引：4，自引：0，他引：4
城市化是世界各国发展的共同趋势，是人类文明和进步的标志。论文简述了国内外城市环境地质工作的历史发展，着重论述了城市地质工作的内容，指出我国城市环境地质中存在的问题。如地面沉降、地裂缝、岩溶塌陷等地质灾害及水资源短缺、城市废弃物处置以及特殊岩土环境问题。为了提高城市规划和确保城市可持续发展，仅从以下5个方面提出了我国城市地质工作的方向：(1)城市地质环境条件、地质资源综合调查评价；(2)城市主要环境地质问题调查；(3)城市群、城市密集区环境地质适宜性综合评价；(4)城市环境地质综合研究；(5)城市环境地质信息系统建设。 相似文献
18.
D. Banerjee M.Sc. M.Phil. Ph.D. S. K. Chakraborty M.Sc. Ph.D. S. Bhattacharyya B.E. M.E. Ph.D. A. Gangopadhyay M.Sc. Ph.D. 《International Journal of Environmental Science and Technology》2009,6(2):325-335
The present study aims to compute the temporal and spatial distribution of road traffic induced noise pollution in an urban environment by monitoring and mapping. The study area was the entire Asansol city of West Bengal, India. A total of 35 locations were selected for collection of data, classified as industrial, commercial, residential, sensitive and mixed areas according to the national regulatory standards. Noise recordings were conducted during morning and night hours. Day time Leq level ranged between 51.2 and 89.0 dB(A), whereas it ranged between 43.5 and 81.9 dB(A) during night. The average Ldn value was 73.28 ±8.51 dB(A) (Range: 55.1–87.3); The traffic noise index was 80.62 ± 15.88 dB(A) (Range: 49.4–115.8). The computed data were mapped by utilization of Geographic information system methodology that allowed the visualization and identification of the extent and distribution of sound pollution across the study area. This proves to be an ideal tool for carrying out noise impact assessments in urban settings. The study reveals that present noise level in all the locations exceeds the prescribed limit. Based on the finding, it can be mentioned that the population in this industrial town are exposed to significantly high noise level, which is caused mostly due to road traffic. The study reveals that vulnerable establishments like schools and hospitals are subjected to significantly high noise level throughout the day and immediate mitigatory measures are required to alleviate the problem. 相似文献
19.
A. Chudnovsky A. Lyapustin Y. Wang C. Tang J. Schwartz P. Koutrakis 《Central European Journal of Geosciences》2014,6(1):17-26
The Moderate Resolution Imaging Spectroradiometer (MODIS) provides daily global coverage, but the 10 km resolution of its aerosol optical depth (AOD) product is not suitable for studying spatial variability of aerosols in urban areas. Recently, a new Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm was developed for MODIS which provides AOD at 1 km resolution. Using MAIAC data, the relationship between MAIAC AOD and PM2.5 as measured by the 27 EPA ground monitoring stations was investigated. These results were also compared to conventional MODIS 10 km AOD retrievals (MOD04) for the same days and locations. The coefficients of determination for MOD04 and for MAIAC are R2 =0.45 and 0.50 respectively, suggested that AOD is a reasonably good proxy for PM2.5 ground concentrations. Finally, we studied the relationship between PM2.5 and AOD at the intra-urban scale (?10 km) in Boston. The fine resolution results indicated spatial variability in particle concentration at a sub-10 kilometer scale. A local analysis for the Boston area showed that the AOD-PM2.5 relationship does not depend on relative humidity and air temperatures below ～7 °C. The correlation improves for temperatures above 7–16 °C. We found no dependence on the boundary layer height except when the former was in the range 250–500 m. Finally, we apply a mixed effects model approach to MAIAC aerosol optical depth (AOD) retrievals from MODIS to predict PM2.5 concentrations within the greater Boston area. With this approach we can control for the inherent day-to-day variability in the AOD-PM2.5 relationship, which depends on time-varying parameters such as particle optical properties, vertical and diurnal concentration profiles and ground surface reflectance. Our results show that the model-predicted PM2.5 mass concentrations are highly correlated with the actual observations (out-of-sample R2 of 0.86). Therefore, adjustment for the daily variability in the AOD-PM2.5 relationship provides a means for obtaining spatially-resolved PM2.5 concentrations. 相似文献
20.
Claire Bénit-Gbaffou 《Geoforum》2008,39(6):1933-1950
The paper questions the pluralization of policing devices and security agents across the Johannesburg metropolitan area, which has been accelerated and actually encouraged by public policies in the post-apartheid period. Are the various security initiatives and networks coordinated in a metropolitan security “system” – the regulation of which would need to be analysed – or does their development lead to urban fragmentation? Based on an analysis of an extensive documentation of security services, as well as a series of interviews with involved (street level) actors, different dimensions of potential urban fragmentation linked to security are examined: spatial fragmentation, with the development of road closures and their contestation; financial fragmentation, emblematised by business improvement districts encouraged by the municipality; and political fragmentation, as reflected by the analysis of the broader security policy framework. The paper argues that although the integrated vision of Johannesburg’s policing creates the basis for redistribution of resources and forms of policing regulation at a metropolitan level (in contrast with the apartheid period), the choice of neo-liberal urban policies, of which security strategies form a part, tends to encourage policing fragmentation, or in other words, the differential and unequal provision of security services according to place, income and race. 相似文献