Showing papers on "Urban climate published in 1994"

Chicago's urban forest ecosystem: results of the Chicago Urban Forest Climate Project

Abstract: Results of the 3-year Chicago Urban Forest Climate Project indicate that there are an estimated 50.8 million trees in the Chicago area of Cook and DuPage Counties; 66 percent of these trees rated in good or excellent condition. During 1991, trees in the Chicago area removed an estimated 6,145 tons of air pollutants, providing air cleansing valued at $9.2 million dollars, These trees also sequester approximately 155,000 tons of carbon per year, and provide residential heating and cooling energy savings that, in turn, reduce carbon emissions from power plants by about 12,600 tons annually. Shade, lower summer air temperatures, and a reduction in windspeed associated with increasing tree cover by 10 percent can lower total heating and cooling energy use by 5 to 10 percent annually ($50 to $90 per dwelling unit). The projected net present value of investment in planting and care of 95,000 trees in Chicago is $38 million ($402 per planted tree), indicating that the long-term benefits of trees are more than twice their costs. Policy and program opportunities to strengthen the connection between city residents and city trees are presented.

Intensity and form of the urban heat island in barcelona

Abstract: A statistical analysis of the differences between the daily minima in the centre of Barcelona and those of the airport, supplemented by temperature readings taken along a number of transects through the urban area, have revealed the intensity of the heat island effect, which reaches a maximum intensity of 8°C. It was also possible to plot the spatial configuration of the latter.

Urbanization and Rural- Urban Migration in China since 1982: A New Baseline

Abstract: It would not be an exaggeration to say that the People's Republic of China has one of the world's most complex systems of defining urban population. As evidenced by the massive literature generated, China watchers in the West have expended an enormous amount of energy in trying to understand the Chinese system. About a decade ago, in one of the apparently futile quests, the size of the Chinese urban population was declared an insoluble "enigma" (Orleans and Burnham, 1984). Today we are, of course, better off: the baffling mysteries surrounding China's urban population size between 1949 and 1982 have since been cleared up through the assiduous work of many scholars (Chan and Xu, 1985; Ma and Cui, 1987). In rapidly changing China, however, recent developments in the definition of what is "urban" and urban boundaries since 1983 have, among other things, created many new problems for urbanists in their attempt to understand urbanization and migration in mainland China in the 1980s. As will be explained in detail later, two existing urban population series were in use between 1983 and 1989 (Table 1, cols. 2 and 8), but neither is satisfactory for any analytical purpose. Although almost all

Surface description for urban climate studies: A gis based methodology

Abstract: In order to understand the nature of the urban climate, predict the effects of urbanization, or attempt to ameliorate some of the negative hydroclimatic effects of urbanization, it is necessary to have a good understanding of the role and significance of the urban surface. This paper presents a methodology which uses GIS to represent the characteristics and morphology of the urban surface, which can be used to describe a site objectively, model fluxes, or ensure spatial consistency between measured and modelled data, all of which can vary through time. The methodology is illustrated with respect to Chicago, Illinois. Surface data collected at three spatial scales were used to construct a georeferenced database which was linked to an objective, dynamic accessing system. Spatial variability of surface cover, derived hydroclimatic attributes, and modelled fluxes associated with changes in the urban environment are used to illustrate potential applications of the approach.

Urban Environmental Management: Environmental Change and Urban Design

Abstract: The urban environment environmental change urban metabolism urban pathology urban impacts on the air urban impacts on the ground and water the ecological city Toronto initiatives.

An analysis of the circulation characteristics and energy budget of a dry, asymmetric, east-west urban canyon. I: Circulation characteristics

Abstract: Wind characteristics within urban canyons are of considerable significance for pollution diffusion, for assessing the nature of the atmospheric environment at street level, and in determining the energy budget of the canyon. This study presents an analysis of the circulation characteristics for a deep, east-west, asymmetric urban canyon (located in Columbus, Ohio, USA), based on measurements of ambient wind at roof level, vertical velocities at the canyon-top, and within-canyon horizontal winds. Canyon-top vertical velocity was normally directed upward, even with cross-canyon winds, indicating along-canyon horizontal convergence. Its speed was approximately related to the magnitude of the southerly, easterly, and westerly components of the roof-level wind. Three-fifths of the data sets showed evidence of a vortex circulation superimposed upon the mean vertical motion, although its speed and direction were not clearly related to the direction of the cross-canyon wind. Some of the perplexing aspects of the results may be attributable to the asymmetric structure of the canyon. Overall, these results suggest that wind fields within and above urban canyons may not be as simply as empirical studies hitherto have suggested and that attempts at modelling these characteristics of the urban climate must recognize this.

Managing Urban Environmental Quality in Asia

Abstract: The Bank has markedly strengthened its capacities and approaches over the past four years to deal more effectively with Asia Region environmental issues in all sectors. This is particularly true for urban development. Without substantial improvement in their management, many Asian cities could become the more polluted human settlements in the world, slow down much of the region's economic growth, and generate a major portion of the hydrocarbons and other pollutants responsible for global environmental degradation. However, Asia's rapid economic growth also offers the potential to solve many of the urban environmental problems. If substantial further growth of Asia's cities cannot be avoided and if the environmental disasters that could be associated with that growth are to be prevented, urban environmental quality management (UEQM) must be substantially improved through the region. This paper offers practical suggestions for improving UEQM through building institutional capacity and establishing best practice in major urban sectors.

The need for a national urbanization policy in Nepal.

Abstract: There is a need for a national urbanization policy in Nepal as a means of redressing regional disparities in development between the hills the Kathmandu Valley and the Terai versus rural and urban areas A settlement system would complement urban and rural development and reduce dependency on India An urbanization policy would be both systematic and guided by public and private investment in existing urban and rural settlements Regional investment in development would contribute to commercialization and agricultural industrialization (development and linkage of market towns and service centers strengthening of basic infrastructure and land use patterns strengthening of urban areas around transportation centers promoting nonfarm employment opportunities establishing strong financial and technical institutions in middle-sized cities and strengthening municipalities mobilization of local resources and financing) Nepal has been one of the least developed countries in its region The agricultural economy provides economic support for 80% of total population In 1991 density was 130 person per sq km 9% of the total population live in urban areas but the rate of urban growth is the highest among South Asian Regional Cooperation countries (73% in Nepal compared to 61% in Bangladesh and 37% in India) Rural markets and towns are rapidly becoming urbanized but without basic infrastructure The spatial component of urbanization must be emphasized Total population increased in the Terai from 37% in 1971 to 47% in 1991 which increased population density by 31% but not cultivation Harsh physical conditions in mountainous regions and lack of cultivable land are push factors Pull factors are employment opportunities in emerging urban centers and the availability of agricultural employment in the Terai Movement to lowlands is enhanced by the eradication of malaria 53% of the urban population is in the Terai in 1991 which also has 65% of cultivable land 35% of roads and 63% of industry Urban settlements increased from 10 in 1951 to 33 in 1987 and 36 in 1991 In the Terai the increases are from five to 21 urban centers The central and eastern region have experienced faster urban growth than the other three regions Kathmandu is the most populated urban center followed by Biratnagar Pokhara and Birganj Government ministries are ill-equipped to handle the technical and manpower needs in the process of urbanization

Aspects of preservation, maintenance and management of the urban forest in brazil

Abstract: This paper presents the treatment given to the urban forest in Brazil focusing on the legal, administrative, technical, educational and economical aspects. It lists some of the tree species most used in urban plantings in Brazil, their families and botanical names, as well as their average height on the streets. It also describes the creation of the Brazilian Society of Urban Forestry, its objectives and main programs. Brazil is the fifth largest country in the world, with a territory of 8.5 million km2, It is situated West of the Greenwich Meridian and is cut across in the North by the Equator. It has many climatic, veg- etation and altitude differences, which lead to the formation of different landscapes. Aproximately 60% of the Brazilian territory is situated in the tropics. It has 150 million inhabit- ants, with 75% concentrated in urban areas. The population growth, the disorganized occupation of the land , the economic and social problems, the real estate speculation, and the lack of an environmental preservation ethic all contribute strongly to the reduction of the remaining natural vegetation in urban areas. Presently, there is a growing awareness about environmental issues, and management and preservation of the urban forest have achieved a prominent position in Brazil. Urban Forestry - Concept and Importance

[Thirty years of urban dynamics in Romania: between homogeneous and specific regional development].

Abstract: It is necessary to give a brief account of the major characteristics of recent urban dynamics in Bucharest (a) because of the impact of images on urban changes and (b) because urbanisation in Romania took place at a late stage and at a very moderate pace (50% in 1985). The urbanisation policy tended towards uniformity which has resulted in medium-sized cities being over-represented in the urban network....The first urban changes to emerge as a result of the post-socialist transition are a consequence of the effects of the size of cities on the one hand and of the revival of historical provinces on the other. (SUMMARY IN ENG AND RUM) (EXCERPT)

The environmental impacts of changing urban structure in the south eastern growth area of melbourne

Abstract: The rapid spread of urban Australia is often seen as increasing travel and pollution. The development of self contained cities in outer areas may enable people to work, live and recreate locally, hence decreasing travel and reducing some of the concerns about outward growth. This paper examines the Economically Sustainable Development and National Greenhouse Strategies recommendations on urban form relating to sustainable development andthe reduction in greenhouse emissions. It compares the environmental impacts of two types of urban development in the context of different urban forms. The south eastern growth area of Melbourne is chosen since it represents an area of considerable population growth. (a) For the covering entry of this conference, see IRRD abstract no 861490.

Urban growth in Korea, 1970-1980 An application of the human ecological perspective

Abstract: This study supports the ecological perspective proposed by Duncan (population environment organization and technology) explaining urban population growth. Data were obtained from the 1970 and 1980 Korean Population Census and Korean Municipal Yearbook on cities with a minimum size of 20000-50000 people (108 cities and towns). Urban growth is most strongly influenced by indigenous labor surplus and the population potential of the city to be in contact with another city. Nine multiple regression variables explained just under 66% of the variance in urban growth. Net migration was influential among those aged 15-24 years. The extent of differentiation of industry affected net migration only among those aged 15-24 years and those aged 35-44 years. Population redistribution was more affected directly by changes in industrial organization and migration was affected indirectly by environmental and technological effects on organization. Urban growth through migration of older age groups was affected by government expenditure on public works. Urban growth was not much affected by transportation/communication concentration manufacturing concentration urban labor surplus population size and site. Urban growth was viewed as the interaction between the unemployment rate and the urban wage following Todaros equilibrium models. In Korea larger cities only grew faster during the 1960s. By the 1970s upper middle-sized cities grew faster. Location was not a significant factor in explaining urban growth but growth was rapid along a corridor within 100 km from Seoul and 50 km from Pusan the second largest city in Korea. Caution was urged in interpreting Koreas ecological urban growth patterns as indicative of developing countries.

Urban Warming and Future Metropolis

Abstract: The rapid growth of industrialization and urbanization due to concentration of economic and social functions in the urban areas have made the urban environment worse and worse. Particularly, in most of urban cities, it has become more and more distinct that the high density of energy consumption is causing environment problems including the rise in temperature of the urban atmosphere, i.e. urban warming, and air pollution. According to the present simulation for urban warming in Tokyo metropolitan area in 2031, the maximum temperature will appear in Otemchi (center of Tokyo) and it will exceed 43°C. This drastic temperature increase indicates that the future Tokyo will be no longer comfortable for inhabitants. In order to work out a counterplan to prevent further deteorioration of urban thermal environment, the effect of tree planting and vegetation was taken into consideration in this paper.

Effect of urbanization in a coastal region on sea breeze and urban thermal environment

Abstract: Effect of land use development in a coastal region on heat island phenomenon is studied numerically by an urban climate model that employs the k-e turbulence model and an eddy diffusivity model for the transport of momentum, temperature and moisture in the Eckman layer together with a heat balance model for the surface boundary layer and the soil layer. Numerical simulations are carried out for a simplified terrain which consists of sea and land. Changes in wind velocity, temperature and heat fluxes are discussed for three types of land use, that is, land surfaces are 1) covered by grass, 2) urbanized as residential area and 3) further developed in a coastal region as business center. It is clarified in the urbanized area that decrease of latent heat flux and increase of sensible heat flux at urban surface raise temperature in the daytime. Urban canopy intensifies sensible heat transfer, leading to higher air temperature. Sea breeze is blocked by the increased roughness in urbanized zone, resulting in the reduced cooling effect of sea breeze.

Effect of land use on urban heat environment

Abstract: .^Effect of land use on heat island is studied numerically by an urban climate model which ^employs the k e turbulence model and an eddy diffusivity model for wind, temperature land moisture fields together with a heat budget model for surface boundary layer and soil ijayer. Simulations were performed for a simplified terrain which consists of sea and land. *'i i > •E i i i •E__ji i i-J1 I iri1 _!•E_._ t

Structure of Evaluating the Living Environment by Urban Inhabitants:A Case Study of River Environment in Urban Areas

Abstract: During the periods of high economic growth, river environment in urban areas has undergone a remarkable change and lost the amenities, caused by the improvements are given priority to flood control and water use.Recently, ensuring the amenity and healthiness in river environment that is regarded as important with the improvement of civil life. Thus, the conservation of ecology, improving water quality and water amentiry is promoting as political action.This study purposed to obtain an expressly information for the planning of river improvement which towards a high quality life. For the purpose, we investigated inhabitant's consciousness of evaluating river environment as a living environmental factor by questionnaire survey, and attempted to explain the structure of inhabitant's consciousness as quantitative relation by using the Analytic Hierarchy Process (AHP) technique. In result, following acknowledgments were given.1) There is a growing need for the improvement of river environment about water quality, water amenity and ecology, inhabitants recognize that rever environment is a part of the nature in living environment.2) To confirmed flood control is the most important function that based on giving the largest priority (53.1%) to ‘flood control, ’ and to keep safety that is the most basic function.3) According to that ‘environmental function’ is given priority (28.1%) in the second place, inhabitants have a need of the nature in river space. It also means that ‘conservation of ecology’ has higher priority (10.2%) compared with 15 items on same level of the hierarchy structure.4) According to that ‘estimating ecological river environement’ is given the largest priority (41.0%) in alternatives, the conservation of ecology in river space has a direction that satisfies inhabitant's preference.These results give suggestions a growing need to measure and evaluate ‘nonuse value’ of river environment.