Showing papers on "Urban climate published in 2005"

The Effects of Urban Patterns on Ecosystem Function

Abstract: Urban ecological systems are characterized by complex interactions among social, economic, institutional, and environmental variables. These interactions generate complex human-dominated landscapes...

Benefits and uses of urban forests and trees

Abstract: Trees and forests are, because of seasonal changes and their size, shape, and color, the most prominent elements of urban nature. Their benefits and uses range from intangible psychological and aesthetic benefits to amelioration of urban climate and mitigation of air pollution. Historically the main benefits of urban trees and forests relate to health, aesthetic and recreational benefits in industrialized cities. Moreover, green areas have provided people with subsistence by providing food, fodder, fuel, wood and timber for construction (see Chap. 2). Today, woodland, woods and trees are important to people especially through symbolizing personal, local, community and cultural meanings. They provide aesthetic enjoyment and create a pleasant environment for different outdoor activities. Woodland can provide an experience of nature in the middle of urban life. In particular, old woodland with big trees may provide urban people with the opportunity to recover from daily stress, revive memories and regain confidence. There is also an important educational value of urban forests. Contact with trees, in particular for children, can help people learn about nature and natural processes in an otherwise artificial environment. Urban trees and woodland also contribute to an attractive green townscape and thus communicate the image of a positive, nature-oriented city. Indirectly, urban trees and forests can promote tourism and enhance economic development. At the local level trees contribute to the quality of housing and working environments and their benefits are reflected in property values. The same urban woodland areas and trees may have multiple benefits that reinforce each other. Recreational woodland, for example, also reduces wind speed and traffic noise as well as improves the landscape in a nearby residential area. To a certain extent the distinction between different categories of benefits is artificial. However benefits have their own special features and therefore can be presented separately (Table 4.1). While these benefits of urban woodland, other tree stands and individual trees are not new they are still insufficiently recognised in urban planning and development processes (see Chap. 5). There is need to provide more knowledge on the role of urban woodland and trees in improvement of the environment and relate this to their social functions such as fostering mental and physical health. This chapter aims to give insight into the current state of knowledge about benefits and uses of urban forests and trees in Europe. This is a difficult enterprise due to the complexity of the European continent. Urban forest research is largely national or even Benefits and Uses of Urban Forests and Trees

The Effects of Human Socioeconomic Status and Cultural Characteristics on Urban Patterns of Biodiversity

Abstract: We present evidence that there can be substantial variation in species richness in residential areas differing in their socioeconomic and cultural characteristics. Many analyses of the impacts of urbanization on biodiversity rely on traditional "urban-to-rural" gradient measures, such as distance from urban center or population density, and thus can fail to account for the ways in which human socioeconomic and cultural characteristics are shaping the human-environment interaction and ecological outcomes. This influence of residential values and economic resources on biodiversity within the urban matrix has implications for human quality of life, for urban conservation strategies, and for urban planning.

Impacts of flooding and climate change on urban transportation: A systemwide performance assessment of the Boston Metro Area

Abstract: Global climate change is likely to affect urban infrastructure through sea level rise and increased frequency of extreme events. This paper assesses the potential impact of climate change on the system-wide performance of transportation networks using the Boston Metro Area as a case study. The methodology integrates projected changes in land use, demographic and climatic conditions into the urban transportation modeling system in order to explore the relative impacts of global warming on the system performance due to additional riverine and coastal flooding. Results indicate almost a doubling in delays and lost trips. These impacts are significant, but probably not large enough to justify a major effort for adapting the physical infrastructure to expected climatic conditions, except for some key links.

Decline and sprawl: an evolving type of urban development – observed in Liverpool and Leipzig1

Abstract: Much of the empirical research on urban sprawl has been carried out in North America and most theoretical studies on this problem have been concerned with expanding urban areas. This study differs, firstly in that it is concerned with sprawl in two European cities, Liverpool in England and Leipzig in Germany, and secondly because both these cities are in decline. This presents an opportunity to explore whether the process of urban sprawl is somehow specific in a situation of urban decline and what its outcomes might be for both urban form and urban policy.

Projected Urban Growth (2000 - 2050) and Its Estimated Impact on the US Forest Resource

Abstract: Urban land in the United States is projected to increase from 3.1% in 2000 to 8.1% in 2050, an area of 392,400 km2, which is larger than the state of Montana. By 2050, four states (Rhode Island, New Jersey, Massachusetts, and Connecticut) are projected to be more than one-half urban land. The total projected amount of US forestland estimated to be subsumed by urbanization between 2000 and 2050 is about 118,300 km2, an area approximately the size of Pennsylvania. Because of this urban growth, more regional planning and management may be needed to sustain forest products and ecosystem services required by a growing urban population.

Urban Growth in Chengdu, Western China: Application of Remote Sensing to Assess Planning and Policy Outcomes:

Abstract: The majority of studies on Chinese urbanization have been focused on coastal areas, with little attention given to urban centers in the west. Western provinces, however, will unquestionably undergo significant urban change in the future as a result of the ‘Go West’ policy initiated in the 1990s. In this paper the authors examine the relationship between drivers of urban growth and land-use outcomes in Chengdu, capital of the western province of Sichuan, China. In the first part of this research, remotely sensed data are used to map changes in land cover in the greater Chengdu area and to investigate the spatial distribution of development with use of landscape metrics along seven urban-to-rural transects identified as key corridors of growth. Results indicate that the urbanized area increased by more than 350% between 1978 and 2002 in three distinct spatial trends: (a) near the urban fringe in all directions prior to 1990, (b) along transportation corridors, ring roads, and near satellite cities after 199...

Gender-specific out-migration, deforestation and urbanization in the Ecuadorian Amazon

Abstract: The Ecuadorian Amazon, one of the richest reserves of biodiversity in the world, has faced one of the highest rates of deforestation of any Amazonian nation. Most of this forest elimination has been caused by agricultural colonization that followed the discovery of oil fields in 1967. Since the 1990s, an increasing process of urbanization has also engendered new patterns of population mobility within the Amazon, along with traditional ways by which rural settlers make their living. However, while very significant in its effects on deforestation, urbanization and regional development, population mobility within the Amazon has hardly been studied at all, as well as the distinct migration patterns between men and women. This paper uses a longitudinal dataset of 250 farm households in the Northern Ecuadorian Amazon to understand differentials between men and women migrants to urban and rural destinations and between men and women non-migrants. First, we use hazard analysis based on the Kaplan–Meier (KM) estimator to obtain the cumulative probability that an individual living in the study area in 1990 or at time t , will out-migrated at some time, t + n , before 1999. Results indicate that out-migration to other rural areas in the Amazon, especially pristine areas is considerably greater than out-migration to the growing, but still incipient, Amazonian urban areas. Furthermore, men are more likely to out-migrate to rural areas than women, while the reverse occurs for urban areas. Difference-of-means tests were employed to examine potential factors accounting for differentials between male and female out-migration to urban and rural areas. Among the key results, relative to men younger women are more likely to out-migrate to urban areas; more difficult access from farms to towns and roads constrains women's migration; and access to new lands in the Amazon–an important cause of further deforestation–is more associated with male out-migration. Economic factors such as engagement in on-farm work, increasing resource scarcity–measured by higher population density at the farm and reduction in farm land on forest and crops–and increase in pasture land are more associated with male out-migration to rural areas. On the other hand, increasing resource scarcity, higher population density and weaker migration networks are more associated with female out-migration to urban areas. Thus, a “vicious cycle” is created: Pressure over land leads to deforestation in most or all farm forest areas and reduces the possibilities for further agricultural extensification (deforestation); out-migration, especially male out-migration, occurs to other rural or forest areas in the Amazon (with women being more likely to choose urban destinations); and, giving continuing population growth and pressures in the new settled areas, new pressures promote further out-migration to rural destinations and unabated deforestation.

The Abiotic Urban Environment: Impact of Urban Growing Conditions on Urban Vegetation

Abstract: ‘Planting of trees in towns should not be given in senseless and untrained hands, because one has to fight against unfavorable soil-, airand other conditions. From noticing them the safe and prospering development of expensive establishments highly depends’ (translated from Fintelmann 1877). Depending on the geographic situation and the urban structure, the environmental conditions in urbanized areas are more or less harsh and they differ from natural growing conditions. The impact of the urban environment on urban vegetation is neither constant in intensity nor periodical. There are numerous constraints that are crucial for the survival and vitality of urban vegetation. This chapter focuses on basic abiotic growing conditions in urbanized areas, on artificial deviations from the natural undisturbed habitat quality in forests that contribute to stresses and threats for urban vegetation. This includes both the qualitative and quantitative impact of different site factors and the time-scale as well: specifics of urban climate, air pollution, constraints and peculiarities of urban hydrological cycles, urban soil conditions in general and in particular unfavorable physical soil properties, unbalanced nutrient supply, soil pollution and fire problems. Possible remedies and precautions to improve growing conditions for urban trees are implicated. In short, the interactions between human activities and the urban environment are discussed to help minimize abiotic stresses that reduce the vigor and vitality especially of trees, and that increase their susceptibility to biotic stresses. Vice versa the impact of urban vegetation on urban ecology is summarized.

The Increasing Influence of Urban Environments on US Forest Management

Abstract: The expansion of urban land promises to have an increasingly significant influence on US forest management in the coming decades. Percent of the coterminous United States classified as urban increased from 2.5% in 1990 to 3.1% in 2000, an area about the size of Vermont and New Hampshire combined. Patterns of urban expansion reveal that increased growth rates are likely in the future. The most urbanized regions of the United States are the Northeast (9.7%) and the Southeast (7.5%), with these regions also exhibiting the greatest increase in percent urban land between 1990 and 2000. Forests near urban communities face a special set of challenges that will only intensify as these communities grow in area, population, and complexity.

Urban Heat and Air Pollution: An Emerging Role for Planners in the Climate Change Debate

Abstract: This article presents empirical evidence linking recent fluctuations in regional temperatures to enhanced ozone formation within the country's 50 largest metropolitan regions. The results of an analysis of regional climate and ozone formation during the 1990s indicate that annual violations of the national ozone standard were more strongly associated with regional temperatures than with the emissions of regulated ozone precursors from mobile and stationary sources. Based on the results of this analysis, I argue that the air quality management strategies outlined in the Clean Air Act may be insufficient to control ozone formation due to ongoing and unanticipated changes in global and regional climate. I further argue that the emergence of urban heat as a significant air “pollutant” demands a strategic response from the field of urban planning. The article concludes with a discussion of the linkages between urban form and regional temperature and outlines a set of design strategies that have proven...

Urban Sprawl, Global Warming and the Limits of Ecological Modernisation

Abstract: The diffusion of urban development results in higher emissions of global warming gases, especially carbon dioxide, because urban sprawl results in higher energy use in transportation and the heating and cooling of spacious homes on the urban periphery. The techniques and politics underlying the diffuse urban form were pioneered in the United States in the late nineteenth century, where landowners and developers sought to use mechanised forms of transportation to increase the value of their land holdings. Today, leading international business organisations seeking to curb anthropogenic climate change gases do not attempt to reform sprawled urban landscapes, but instead promote technological reforms that would allow sprawl to continue. This is because urban sprawl pushes up demand for such consumer durables as automobiles and household appliances. In this article the author describes how the techniques of urban sprawl were developed and championed politically by landholders and developers in the US. The aut...

Changes in traditional urban areas and impacts of urban redevelopment: A case study of three neighbourhoods in Nanjing, China

Abstract: Since market-oriented economy reform, China has experienced significant changes in urban landscapes and the internal structure of cities. Recent studies have provided some insightful understanding into urban changes at a macro-scale, e.g. social and spatial segregation, the division between rural migrants and urban households, changes in land uses. To a lesser extent, urban changes are understood at the microscopic level of the neighbourhood. Urban (re)development has created many new urban landscapes. Meanwhile, traditional old urban areas still constitute a significant proportion of Chinese cities, and normally contain large concentrations of marginal population. Possessing the particular characteristics of long developing history, high population density, and low housing quality, traditional urban areas have also experienced different changes in the post-reform period. This study, based on a field survey of three traditional urban areas in Nanjing, attempts to reveal the built environmental and socio-economic changes which can be partly attributed to different levels of urban redevelopment. More importantly, the study highlights the significance of neighbourhood-based social interaction to marginal population. Against the backdrop of massive urban displacement and rapid redevelopment, it is argued that the effect of dismantling neighbourhoods could be detrimental to a sustainable urban society and the positive social objectives should be seriously considered in the process of urban redevelopment.

Urban and rural dewfall, surface moisture, and associated canopy-level air temperature and humidity measurements for Vancouver, Canada

Abstract: Canopy-level humidity is often less at night during fine weather in a mid-latitude city, compared to its rural surroundings. This feature has been attributed, in part, to reduced urban dew, but links are largely unproven, because urban dew data are rare. In this study, surface moisture (i.e., dew + guttation by blotting) and dewfall (by mini-lysimeter) were measured at rural and urban residential sites in Vancouver, Canada, during the summer of 1996. Air temperature and humidity were measured at both sites, and on rural-to-urban vehicle traverses. Weather and location effects were evident. Humidity data suggested the small (< 1 g m−3) urban moisture excess observed on fine nights was linked to reduced urban dew. For grass, the frequency of moisture events, and surface moisture amounts, were similar for both sites. However, on grass, rural dewfall (mean=0.10 mm per night) was more than urban dewfall (mean=0.07 mm per night). On the other hand, data for a ‘roof’ lysimeter (mean dewfall=0.12 mm per night) showed that an urban roof could rival rural grass as a favoured location for dewfall in Vancouver.

Urban–rural temperature differences in coastal cities: influence of rural sites

Abstract: This paper considers problems in calculating the heat island magnitude of coastal cities. We examined the influence on heat island magnitude (1) when a rural observatory located in an inland area is compared with an urban observatory and (2) when an observatory in an atypical countryside setting is chosen as the rural site. The results showed that the urban–rural temperature difference was bigger in winter than in summer when the rural observatory was located in a relatively inland area in comparison with the corresponding urban observatory. This tendency was more marked at night than in the daytime. When an observatory in an atypical rural setting was used, the urban–rural temperature difference was greater from 11:00 p.m. to midnight in summer. Therefore, only observatories located in typical rural areas and located roughly the same distance from the sea as the corresponding urban observatories should be selected for investigation of urban heat island magnitude. Copyright © 2005 Royal Meteorological Society

Intercomparisons of experimental convective heat transfer coefficients and mass transfer coefficients of urban surfaces

Abstract: The convective heat transfer coefficient (CHTC) of an urban canopy is a crucial parameter for estimating the turbulent heat flux in an urban area. We compared recent experimental research on the CHTC and the mass transfer coefficient (MTC) of urban surfaces in the field and in wind tunnels. Our findings are summarised as follows. Although there is some agreement in the measured values, our overall understanding of the CHTC remains too low for accurate modelling of urban climate.

Urban-rural temperature differences in coastal cities : Influence of rural sites

Abstract: This paper considers problems in calculating the heat island magnitude of coastal cities. We examined the influence on heat island magnitude (1) when a rural observatory located in an inland area is compared with an urban observatory and (2) when an observatory in an atypical countryside setting is chosen as the rural site. The results showed that the urban-rural temperature difference was bigger in winter than in summer when the rural observatory was located in a relatively inland area in comparison with the corresponding urban observatory. This tendency was more marked at night than in the daytime. When an observatory in an atypical rural setting was used, the urban-rural temperature difference was greater from 11 :00 p.m. to midnight in summer. Therefore, only observatories located in typical rural areas and located roughly the same distance from the sea as the corresponding urban observatories should be selected for investigation of urban heat island magnitude.

The Effectiveness of Urban Containment Regimes in Reducing Exurban Sprawl

Abstract: During the 1990s, the exurban landscape grew faster and added more people than urban, suburban, and rural landscapes. In many respects, exurbanization is the quintessential representation of urban sprawl and the problems it poses. More than 100 metropolitan areas across the US attempt to manage exurbanization through various forms of urban containment at regional or subregional scales. In this article, we assess the extent to which urban containment is effective in managing exurban sprawl in the 35 largest metropolitan areas in the US. Through simple cross-section analysis, we found that relative to metropolitan areas without urban containment, those pursuing “strong” containment efforts performed best in reducing exurbaniza- tion. Strong containment programs are those that direct urban development into areas defined by urban containment boundaries and restrict development outside the boundaries. Metropolitan areas with “natural” containment, i.e., where development is constrained because of oceans, mount...

Interactions between thermal advection in frontal zones and the urban heat island of Wrocław, Poland

Abstract: This paper deals with variability in the air temperature field of an urban area during thermal advection, associated with frontal zones, and its interaction with an urban heat island (UHI). Thermal changes experienced in Wroclaw, Poland form the basis of this case study analysis. The discussion also contributes to questions concerning the definition of the UHI and ways to select UHI episodes from existing data sets. It is shown that changes in temperature generated during periods of advection are of short duration, only a few hours at most, but thermal contrasts between various parts of a city at such times are sometimes large, reaching an intensity of 5–6 K, even as large as 9 K. Thus, their intensity is comparable with that of the UHI occurring on cloudless and windless nights. The thermal influence of advection is often greater than that due to urban factors; it is only on occasions with less dynamic advection, that a concentric temperature field is formed due to the modified physical properties of the city. In the majority of cases, the thermal field is non-concentric and this is linked with the location of a frontal zone at any given time. The thermal effects of advection recorded in a data set might easily be viewed as episodes of UHI existence, especially if analysis is conducted based on the data derived from just two stations – one urban the other rural. On occasions when such ‘quasi-UHI’ occur the role of the location of the rural, reference station is also evaluated. Precise definition of the urban heat island can be of significance when conducting comparative studies of the UHI in cities located in different geographical zones and when making an urban climate synthesis.

Urban forest in China: Development patterns, influencing factors and research prospects

Abstract: Urban forest is a very important part of urban ecosystems and provides significant ecosystem services. It benefits urban communities environmentally, aesthetically, recreationally and economically. This article reviews the development status, development patterns and influencing factors of urban forest in China. There are four typical development patterns of urban forest in China: the forest city, garden city, ecological economics and forest greenbelt. Social, climatic, economic and other factors influence urban forest development in China. Social factors include government behaviour, laws and regulations, science and technology, education and Culture, public awareness and participation, ecological planning and management. Climatic factors include rainfall, temperature and Sunlight. Economic factors include urban economic level and funding for urban forest. In future, government, NGOs and the private sector should be considered more in the planning and management of urban forest. The social, climatic and economic factors should be taken into account when improving urban forest management. Research on urban forest from the academic and the management viewpoint should he Strengthened. This can improve the development and management Of Urban forest in China and in other developing Countries.

Rural Population Growth in Sweden in the 1990s: Unexpected Reality or Spatial-Statistical Chimera

Abstract: Though estimating rural population change at first glance seems simple, it in fact involves methodological difficulties and requires the accommodation of definitional ambiguities. This article addresses the matter of urban spillover in rural population development. Simply stated, "urban spillover" here refers to how urban localities tend to push a ring of diffuse urban growth outwards as they expand in area. If constant delimitations of urban localities and rural areas are employed, their definitions will de facto change, and what is actually diffuse urban growth will be treated as rural. If the spatial areas used are constructed from predefined areas (e.g. census enumeration areas), the effect of arbitrary geographical subdivision is added. These effects of urban spillover in different methods of estimating rural population change are illustrated here using Swedish data, which are suitable for this purpose given their high spatial resolution. The data do not support the existence of any actual rural population growth in Sweden in the 1990s, apart from the effects of urban spillover. We also show that urban spillover varies geographically depending on the measurement method used.

Relation between Heat Island Intensity and City Size Indices/Urban Canopy Characteristics in Settlements of Nagano Basin, Japan

Abstract: This paper demonstrates the relation between the heat island intensity and city size indices/urban canopy characteristics. This is accomplished by analyzing the data at 6 settlements on the Nagano basin, Japan, whose population ranges from 3, 300 to 360, 000. The results show that heat island intensities on fine nights and cloudy nights, ΔTu-r are related to the logarithm of the settlement population P, which has one of the highest correlations to the heat island intensity in a city size index such as city area, DID (Densely Inhabitant District) area, DID population and so on. The gradient of regression between ΔTu-r and P is larger on fine nights than on cloudy nights, and is larger on nights with weak wind than on nights with strong wind. The correlation of population with maximum heat island intensity is remarkably high for Japanese settlements.

"Treasure Nightsoil As If It Were Gold:" Economic and Ecological Links between Urban and Rural Areas in Late Imperial Jiangnan

Abstract: This article provides a new perspective to understand what I call “agrarian urbanization” by examining how peasants changed urban life in late imperial Jiangnan. 1 The study of urbanization is not only a matter of tallying the increasing size and number of towns, but also gauging the growing impact of urban activities on the whole society. Furthermore, the urban-rural interaction is rarely one-sided, with the rural as the passive recipient of urban influence. Instead, activities in rural society can have formative influence upon urban development. To measure the extent of urbanization in a society, therefore, we should examine not only population sizes in towns and cities, but also the behavior of people outside the urban settlement. Unfortunately, most studies of urbanization neglect this part of the story. 2 The reason for this neglect is not difficult to find. It lies in the character of urban legends about the largely unknown activities of the rural population.

Detection of urban effect on vegetation in a less built-up Hungarian city by hyperspectral remote sensing

Abstract: Airborne hyperspectral imaging data has been operationally used in geosciences, environmental and agricultural sciences worldwide, and it is increasingly involved in urban-related studies. Up to now, it was the first attempt in Hungary (Gyongyos) applying this technology for object (natural and artificial) identification in urban and suburban areas. It is important for us to focus our study on the spectral feature of different artificial materials and vegetation. The differentiation between different kinds of vegetation is much more efficient in the short wave infrared bands. Thus, this region is the best wavelength to discriminate different vegetation with vegetation indices. Artificial surfaces influence highly the urban climate particularly in summer (vegetation period). That effect can play important role in forming urban heat islands that determine the growing of vegetation as well. The application of this technique to urban ecology (human ecology) and urban land cover mapping remains underdeveloped in Hungary until recently. In order to understand better this feature it was investigated vegetation in the centre of the city, but focusing on a less build-up area.