Showing papers on "Urban climate published in 2001"

Streams in the Urban Landscape

Abstract: The world’s population is concentrated in urban areas. This change in demography has brought landscape transformations that have a number of documented effects on stream ecosystems. The most consistent and pervasive effect is an increase in impervious surface cover within urban catchments, which alters the hydrology and geomorphology of streams. This results in predictable changes in stream habitat. In addition to imperviousness, runoff from urbanized surfaces as well as municipal and industrial discharges result in increased loading of nutrients, metals, pesticides, and other contaminants to streams. These changes result in consistent declines in the richness of algal, invertebrate, and fish communities in urban streams. Although understudied in urban streams, ecosystem processes are also affected by urbanization. Urban streams represent opportunities for ecologists interested in studying disturbance and contributing to more effective landscape management.

Urban ecological systems: linking terrestrial ecological, physical, and socioeconomic components of metropolitan areas

Abstract: Ecological studies of terrestrial urban systems have been approached along several kinds of contrasts: ecology in as opposed to ecology of cities; biogeochemical compared to organismal perspectives, land use planning versus biological, and disciplinary versus interdisciplinary. In order to point out how urban ecological studies are poised for significant integration, we review key aspects of these disparate literatures. We emphasize an open definition of urban systems that accounts for the exchanges of material and influence between cities and surrounding landscapes. Research on ecology in urban systems highlights the nature of the physical environment, including urban climate, hydrology, and soils. Biotic research has studied flora, fauna, and vegetation, including trophic effects of wildlife and pets. Unexpected interactions among soil chemistry, leaf litter quality, and exotic invertebrates exemplify the novel kinds of interactions that can occur in urban systems. Vegetation and faunal responses suggest that the configuration of spatial heterogeneity is especially important in urban systems. This insight parallels the concern in the literature on the ecological dimensions of land use planning. The contrasting approach of ecology of cities has used a strategy of biogeochemical budgets, ecological footprints, and summaries of citywide species richness. Contemporary ecosystem approaches have begun to integrate organismal, nutrient, and energetic approaches, and to show the need for understanding the social dimensions of urban ecology. Social structure and the social allocation of natural and institutional resources are subjects that are well understood within social sciences, and that can be readily accommodated in ecosystem models of metropolitan areas. Likewise, the sophisticated understanding of spatial dimensions of social differentiation has parallels with concepts and data on patch dynamics in ecology and sets the stage for comprehensive understanding of urban ecosystems. The linkages are captured in the human ecosystem framework.

Energy and Climate in the Urban Built Environment

Abstract: Part 1 * On the Built Environment the Urban Influences * Climate and Climate Change * Wind Patterns in Urban Environments * Wind Patterns in Urban Environments * Thermal Balance in the Urban Environment * Heat-island Effect * The Canyon Effect * The Energy Impact of the Urban Environment * Short-wave Radiation * Urban Pollution * The Role of Green Spaces * Appropriate Materials for the Urban Environment * Applied Lighting Technology for Urban Buildings * Active Solar Heating Systems for Urban Areas * Indoor Air Quality and Ventilation in the Urban Environment * Urban Settlements * Part 2 * Guidelines for Integrating Energy Conservation Techniques in Urban Buildings * Examples of Urban Buildings * Appendix * Index

A habitat island approach to conserving birds in urban landscapes: case studies from southern and northern Europe

Abstract: Wildlife conservation in urban habitats is increasingly important due to current urbanization trends. We review the different approaches to studying birds in urban landscapes, and point out the impor- tance of the habitat island ecological theory as a research framework for the management and conservation of urban birds. Based on two comprehensive research projects conducted at urban parks in Spain (Ma- drid) and Finland (Oulu and Rovaniemi), several different issues related to bird conservation in cities are discussed, main findings of these projects are presented, and future research needs are suggested. Urban parks are important biodiversity hotspots in cities. Fragmentation conditions have the same deleterious effects to urban birds as in other fragmented landscapes. Park size accounts for species accumulation in urban parks; this pattern being highly nested. Urban parks of 10-35 ha would contain most of the species recorded in cities, but other indicators related to the probabilities of persistence of the target species should be obtained. Wooded streets can increase urban landscape connectivity by providing alternative habitat for feeding and nesting during the breeding season. Because increasing the size of parks is difficult in cities, enhancement of habitat diversity and resource availability for birds within parks (e.g. nest boxes, winter feeding tables, etc.) appears to be a straightforward way of increasing urban bird diversity. However, human disturbance (pedestrians) should be controlled since it can negatively influence many urban birds. We present a conceptual model for urban bird conservation, which includes three aspects (management, environmental education and research) and new alternatives to promote the involvement of different sectors of the society.

Urban Expansion and the Loss of Prime Agricultural Lands in Puerto Rico

Abstract: In many countries where the economy has shifted from mainly agricultural to industrial, abandoned agricultural lands are lost to urbanization. For more than 4 centuries the Puerto Rican economy depended almost entirely on agriculture, but sociopolitical changes early in the 20th century resulted in a shift to industry. This shift in the economy, and an increase in population, has resulted in an increase in urban areas. This study describes the rate and distribution of urban growth on the island of Puerto Rico from 1977 to 1994 and the resulting influence on potential agricultural lands. Urban extent and growth were determined by interpreting aerial photographs and satellite imagery. The 1994 urban coverage was combined with a soil coverage based on agricultural potential to determine the distribution of urban areas relative to potential farmlands. Analyses showed that in 1977, 11.3% of Puerto Rico was classified as urban. After 17 years, urban areas had increased by 27.4% and urban growth on soils suitable for agriculture had increased by 41.6%. This represents a loss of 6% of potential agricultural lands. If this pattern of encroachment by urban growth into potential farmlands continues, Puerto Rico's potential for food production in the future could be greatly limited.

Monitoring urban expansion with remote sensing in China

Abstract: The Open Policy and Economic Reform has imposed a profound impact on dynamic changes of land-use patterns in many areas of China over the last two decades. Rapid urbanization and industrialization have resulted in a sharp reduction in arable land acreage. A project was carried out in 1997 under the auspices of the China State Land Administration to monitor the dynamics of urban expansion in 100 municipalities throughout China. This paper describes the implementation of the project and reports on some of the results obtained. Landsat Thematic Mapper (TM) images acquired for 1989/1992 and 1996/1997 were used to examine the scope and the speed of urban expansion in this period. Change detection techniques were employed to identify the areas of urban encroachment. Statistics on preceding states of the expanded urban areas were generated and various thematic maps were produced. The results showed that urban development in southern and coastal areas is the fastest, and the highest speed of urban expansion is as...

Gardening to reduce hazard: urban agriculture in Tanzania

Abstract: Urban agriculture is an illegal activity in most African towns and cities, as it is seen to be competing with other, higher value, urban land uses. Despite this, food production occurs throughout the African urban environment and is crucial to the urban economy; providing employment, food security and investment opportunity for a large proportion of the urban population. Urban agriculture also adds value to urban land, bringing unused land into production, reversing degradation and improving the urban landscape. In the context of a rapidly expanding urban population, food production in Dar es Salaam is playing a crucial role in sustaining the city, employing 210000 people. Urban agriculture also has an important role to play in providing a viable land use in the hazard lands of Dar es Salaam, as an alternative to squatter housing which exposes the inhabitants to a substantial risk from flooding. This paper looks at the role that urban agriculture plays in Dar es Salaam and identifies the major actors. Copyright © 2001 John Wiley & Sons, Ltd.

Road Climate in Cities:A Study of the Stockholm Area, South‐East Sweden

Abstract: The difference between air and road surface temperature in urban and rural areas is an important consideration when modelling the road climate. In this study the effect of the urban heat island in the Stockholm area on road climate is examined. Factors such as distance from the city centre, traffic and topography are analysed in order to assess their impact on the spatial variation of road and air temperature. Copyright © 2001 Royal Meteorological Society

An Approach for Measuring Urban Deprivation Change: The Example of East Montréal and the Montréal Urban Community, 1986 – 96:

Abstract: The concept of urban deprivation has emerged as an important theme in urban geography and urban studies. In light of the significant problems and issues affecting cities in North America and Europe there is a growing need for researchers to acquire a better understanding of the process of urban social change. In this paper the author proposes a model of urban deprivation change and applies it with the use of census indicators to East Montreal, a section of the central city, and the Montreal Urban Community. The changing spatial structure and nature of urban deprivation is examined at the neighbourhood level in this study area over the period 1986 – 96. The author finds that urban deprivation is largely an economic problem, with declining conditions apparent throughout a large part of Montreal's central city and in several inner-suburban municipalities. The model, selection of indicators, and statistical techniques presented in this paper can be used as a guide for further research into urban deprivation c...

Assessing the US Urban Forest Resources

Abstract: Urban areas in the conterminous United States doubled in size between 1969 and 1994, and currently cover 3.5 percent of the total land area and contain more than 75 percent of the US population. Urban areas contain approximately 3.8 billion trees with an average tree canopy cover of 27 percent. The extent and variation of urban forests across the 48 states are explored to help build a better understanding of this significant national resource. Urbanization and urban forests are likely to be a significant focus of forestry in the 21st century.

Land Use Change and Competition in the South

Abstract: The amount of land in urban and other special uses increased more than 50 percent since the 1960s in the South. Rural land converted to urban uses is directly related to increases in population in the South. Urban land-use coefficients were estimated to provide a measure of the amount of land converted to urban uses per person added to the population base. These coefficients indicate that from 1974 to 1987 two-thirds to three fourths of an acre of land was converted to urban uses for each person added to the population base. At this rate, about 12.6 million acres are expected to be converted to urban use in the South during the next two decades.

Can Urban Form Affect Transportation Energy Use and Emissions

Abstract: The debate on the type of urban form that is the most efficient with respect to transportation energy consumption and the associated pollutant emissions has produced ambiguous results. This paper contributes to the debate through an analysis of the efficiency of simulated urba nforms for the time period 1991-2021 with the help of IMULATE, an Integrated Transportation and Land Use Model for the Hamilton Census Metropolitan Area. The urban forms analysed are obtained by varying the spatial distribution of the projected household growth in the region. The status quo is compared to a compact urban form and to two multi nucleated forms. The results, albeit ambiguous, demonstrate that the way future scenarios are developed can have a significant impact on inferences drawn from such studies.

Further development of the urban bioclimate model UBIKLIM, taking local wind systems into account

Abstract: The urban bioclimate model UBIKLIM is an application model providing an assessment on the influence of urban climate on human beings. On a calm summer's day with fair weather conditions it calculates the meteorological parameters air temperature, humidity, wind velocity and short and long wave radiation based on a digital height model and appropriate land use information. These meteorological parameters determine the heat exchange conditions of human beings and thus can be analyzed with the help of the Klima-Michel model into physiologically significant terms. The result is a bioclimate map on a scale that is appropriate for climate-related planning in an urban environment. In urban areas lying in a distinct relief, a superimposed wind regime, such as a down valley wind, can modify the bioclimate considerably. Up to now it was not possible for UBIKLIM to take this situation into account. In this point UBIKLIM has been developed further, but its easily applicable character has been preserved. This has been realized, firstly by combining an orographically induced wind field with the one calculated in UBIKLIM as a function of land use esp. of urban structure, and secondly by introducing an algorithm by working out conveyance processes in the direction of the superposed wind field. UBIKLIM fills the gap between meso and micro scale models. Results of the further developed model are shown in the example of the city of Freiburg im Breisgau which is influenced by the distinct relief at the southern edge of the Black Poorest.

Environmental and Energy Impact of the Urban Forest in Arid Zone Cities

Abstract: The massive presence of trees in urban environments, particularly in regions with dry mesothermal climates, generates a significant environmental impact on the open spaces of the public domain and consequently on the enclosed spaces of the private domain. The paper presents the development and the initial results of the utilization of an analytical-computational model, specifically designed to assess the availability of solar radiation on horizontal and vertical surfaces of the urban environment shaded by trees as function of several interrelated variables descriptive of urban morphologies typical of the city of Mendoza, in central-western Argentina. The data generated by the model's utilization will be essential for future studies, aimed at assessing the incidence of trees on the solar potential of urban buildings and on the intensity of the urban heat island effect in cities of the region.

Approach on China's Urbanization Quality

Abstract: Urban modernization consists of urban economic urbanization, urban i nfrastructure modernization and the human modernization. Rural－urban integratio n is considered by the income level of and the related difference of living qual ity between urban and rural residents. This paper argues that the current urbani zation quality in China is not good enough, the 9 metropolitans with over 3 mill ions in population each do not achieve high modernization, great part of them is only on the stage of basic modernization. The rural－urban integration level is also rather low according to its obvious dual economic characteristic. Therefor e, this paper thinks that the steps should be taken to improve China's urbanizat ion quality.

The Impact of Urban Transit on Ecological Environment

Abstract: Urban transit system is an important component of the urban ecological environment It undertakes the transfer and transport function of material, energy and information in this environment And it also maintains the smooth running of city production and consumption However, development of urban traffic promotes and improves social and economical environment, but causes unfavorable effect on the urban ecological and natural environment Increased number of vehicles and traffic volume will made consume large quantities of natural resources such as land and energy.At the same time,there will cause obvious effect on atmospheric and sonic environment、climate and greenhouse gases in urban areas In order to avoid the deterioration trend of the ecological environment caused by urban development, it has been one of our basic duties to study and design the scientific and rational urban green transit system. Thus it will make the city develop econtinuously and improve the ecological environment of the city Urban railway transit system will obviously improve urban heavy traffic and ease the impact on the ecological environment People have realized the importance of the environmental protection.Urban railway transit system has gradually been a major urban mass transit system of a modernized city, due to its high efficiency, low consumption,small pollution as well as its comfort, safety and rapidity Development of urban railway transit system will make positive contributions to improvement of the ecological environment, the continuous urban development and the construction of the 21 century ecotype city

Street canyon microclimate in traditional and modern neighbourhoods in a hot dry climate - a case study in Fez, Morocco

Abstract: The urban climate can vary considerably within cities. In a hot and dry climate, the micro¬climate at street level depends to a large extent on the urban geometry and building density. To be able to plan and design comfortable urban areas in the future, it is important to understand how different urban textures influence the climate. This paper deals with a case study in Fez, Morocco, where climate measurements took place in two entirely different types of neighbourhoods: a modern, suburban area with wide streets and many open spaces and a traditional, dense neighbourhood in the old city. The results show significant differences between the two neighbourhoods. In both summer and winter the minimum temperature was 2–4°C lower in the modern area, and the maximum temperature was about 10°C higher. In summer the modern area was extremely uncomfortable whereas the traditional was within the comfort zone. In winter neither area achieved comfort, but the modern was better.

A model of urban growth with endogenous suburban production centers

Abstract: This paper presents a theoretical model of the spatial growth of an urban area. Its primary contribution is that suburban production centers arise as small, independent landowners respond to market forces. Other models impose subcenters exogenously and require action by large developers or government agencies. The model predicts almost no undeveloped land is present in struggling cities, but urban sprawl is the hallmark of a growing metropolitan area. There is also anticipatory sprawl: even while all industrial development is concentrated in the central city, a leapfrog zone may sprout between two residential zones in the suburbs.

Application of landscape ecology in urban planning and management

Abstract: As a typical artificial landscape, the spatial structure of city is the type of high collective landscape and the function of city appears as the diversities of culture, high capability and high energy flow Landscape ecology on city includes urban spatial structure and ecological process, urban landscape scene and urban ecological construction and urban landscape planning The most direct application of landscape ecology on city is landscape planning This paper, firstly, discusses on the valuations of urban landscape quality and value which include the valuation of landscape aesthetics and the capability of landscape vision The topic of this paper is urban spatial structure and the principles on landscape planning, which involves urban spatial patterns, the corridor influence of urban spatial extension and the analysis on the spatial structure of urban greenbelt system Based on the cases of greenbelt systems in Shanghai and Guangzhou, the authors analyze on the landscape change of the ecotone landscape between urban and rural At the same time, the characteristics of the processes of urbanization are described by urban landscape patterns and its dynamics according to the typical researches in Shanghai and Shenyang

Urban climate and its influence on energy consumption a case study in two brazilian cities

Abstract: Two prototype office buildings with low internal gains were simulated using DOE2 software to evaluate its energy consumption in different urban microclimates. Weather data from two weather stations were used: in Rio de Janeiro – Santos Dumont local airport and Antonio Carlos Jobim International Airport – and in Florianopolis – Hercilio Luz International Airport and LABSOLAR at Federal University of Santa Catarina. One prototype was designed to be more sensitive to the external environment and the other, less sensitive. The weather files of 3 stations did not have solar radiation data. Solar radiation was estimated from cloud cover based in a different model than that used by DOE 2.1-E that was calibrated with satellite data. This paper presents the comparison of the results of total building electric energy consumption for the two different climatic data files in each city. It presents also the differences in some weather data variables, dry bulb temperature, solar radiation and wind speed, found in each city. Site characteristics, such as urban occupation or location into the city, are factors that affected simulation results. Also, building components characteristics modify consumption according to the site where the prototype is simulated.

OBSERVATIONS ON THE THERMAL EFFECTS OF RIVER WATER ON URBAN CLIMATE : Study on heat budget on water surface and its effects on surrounding areas of Sumida River

Abstract: Water bodies in urban area have been expected to mitigate the urban heat island as well as green space. In this paper, we showed the results of observations about heat budget at river water and moving observations to clarify horizontal extent of its thermal effects. Diurnal variations of sensible heat flux estimated by several methods corresponded closely with each other., though these values didn’t exceed 100W/m2 even in the peak about midday. Estimated heat storage term occupied more than 90% of net radiation during daytime. According to the numerical simulation, observed water temperature variation required equivalent heat conductivity for actual stirred water about forty times as much as that of stagnant water. This heat balance is completely different from that of green space characterized large latent heat flux. On the other hand, horizontal sensible heat flux from adjacent built-up area to the river space also estimated by eddy correlation method at riverside terrace. Turbulent heat flux across the river-edge amounted to 250 W/m2 in daytime, which greatly surpassed vertical sensible heat flux at water surface. The horizontal limits of river-effect along the street crossing the river were about 300m from river-edge, and there was no clear relation between this limits and wind speed.

Forest resources, urbanisation and poverty: an interdisciplinary study

Abstract: SUMMARY Although most of the world's poor live in rural areas, the share living in urban areas is rising as urbanisation spreads. The urban poor may be seen as heavily dependent on cash incomes to meet their basic needs, having low portfolios of physical assets, as living in cramped conditions often without access to basic services such as clean water, and surrounded by a polluted environment. The role that forest products play in livelihoods, both as providers of goods and services, and as the focus of occupations must be understood in order to define future forest policy and research priorities to benefit the poor in urban and peri-urban areas. A case study survey of six cities in Asia, Africa and Latin America looked specifically at the use of forest and tree products and services by poor urban households, and the livelihoods created in urban areas through their supply. This article defines the problems of the urban poor arising from their lack of access to forest resources and makes recommendations fo...

Dynamic of the Urban Greenspace System and Its Relationship with Landuse ——Case Study of the Southwest Shanghai City

Abstract: Taking the southwest Shanghai city as an example,the traits and dynamic of the urban green space system including public green land,irrigated field,vegetable plot and water body of the southwest urban rural ecotone in Shanghai was discussed in this paper.Meanwhile, A comparison between urban green space system and land use in this area was made.Finally,several strategic measures to ensure the sustainable development of the urban green space system in the urban rural ecotone are herein proposed after a comprehensive analysis.

Urbanization and urban quality

Abstract: The author summaries the problems in the process of urbanizatoin both of China and abroad,and furthermore point out that quality,characteristics,and sustainability should be employed in the evaluation of urbanization.