Wind Climate In Cities

If one surveys the development of wind engineering, one comes to the conclusion that the challenge of urban climatology is one of the most important remaining tasks for the wind engineers. But what distinguishes wind engineering in urban areas from conventional wind engineering? Principally, the fact that the effects studied are usually unique to a particular situation, requiring consideration of the surroundings of the buildings. In the past, modelling criteria have been developed that make it possible to solve environmental problems with great confidence, and studies validated the models: at least in a neutrally stratified atmosphere. The approach adopted in the book is that of applied fluid mechanics, since this forms the basis for the evaluation of the urban wind field. Variables for air quality or loads are problem specific, or even random, and methods for studying them are based on risk analysis, which is also presented. Criteria are developed for a systematic approach to urban wind engineering problems, including parameter studies. The five sections of the book are: Fundamentals of urban boundary layer and dispersion; Forces on complex structures in built-up areas; Air pollution in cities; Numerical solution techniques; and Posters. A subject index is included.

If one surveys the development of wind engineering, one comes to the conclusion that the challenge of urban climatology is one of the most important remaining tasks for the wind engineers. But what distinguishes wind engineering in urban areas from conventional wind engineering? Principally, the fact that the effects studied are usually unique to a particular situation, requiring consideration of the surroundings of the buildings. In the past, modelling criteria have been developed that make it possible to solve environmental problems with great confidence, and studies validated the models: at least in a neutrally stratified atmosphere. The approach adopted in the book is that of applied fluid mechanics, since this forms the basis for the evaluation of the urban wind field. Variables for air quality or loads are problem specific, or even random, and methods for studying them are based on risk analysis, which is also presented. Criteria are developed for a systematic approach to urban wind engineering problems, including parameter studies. The five sections of the book are: Fundamentals of urban boundary layer and dispersion; Forces on complex structures in built-up areas; Air pollution in cities; Numerical solution techniques; and Posters. A subject index is included.

In the context of urbanization and compact urban living, conventional experience-based planning and design often cannot adequately address the serious environmental issues, such as thermal comfort and air quality. The ultimate goal of this book is to facilitate a paradigm shift from the conventional experience-based ways to a more scientific, evidence-based process of decision making in both urban planning and architectural design stage. This book introduces novel yet practical modelling and mapping methods, and provides scientific understandings of the urban typologies and wind environment from the urban to building scale through real examples and case studies. The tools provided in this book aid a systematic implementation of environmental information from urban planning to building design by making wind information more accessible to both urban planners and architects, and significantly increasing the impact of urban climate information on the practical urban planning and design. This book is a useful reference book to architectural postgraduates, design practitioners and planners, urban climate researchers, as well as policy makers for developing future livable and sustainable cities.

Spatial production is inevitably linked to climate issues. In the course of the last 15 years the debate on sustainable architecture and ecological urbanism has risen like a phoenix from the ashes. Architects and urban planners, as well as administrative bodies and developers, face a new responsibility in terms of the complexity of their conventional design and planning methods. Increasing awareness of climate issues in the design process has the potential once more to make architecture in the future more site-specific, giving it back its contextual relevancy. City and Wind - Climate as an Architectural Instrument is a call to see architecture not just as a means of protecting us against the climate, but also as a way of bringing us back to it.

The first full synthesis of modern scientific and applied research on urban climates, suitable for students and researchers alike.

The mixing-layer height and the average wind speed within the mixing layer were calculated twice for each day of a 5-year record of upper air observations at 62 National Weather Service stations int he contiguous United States. The times of day of these calculations are morning and mid-afternoon. A rough allowance was made for effects of the urban "heat island" on the morning mixing heights. The morning and afternoon times coincide approximately with those of maximum and secondary minimum concentrations of slow-reacting pollutants in cities. These calculations illustrate the typical large diurnal variation in atmospheric dispersion. Twenty charts present seasonal and annual, and morning and afternoon mean mixing heights and wind speeds. A model of some general dispersion features over urban areas is described in which the normalized pollutant concentration averaged over a city is a function of mixing height, wind speed, and city size (distance the wind travels across the city). Frequency values of mixing height by wind speed are used with the model to calculate average normalized concentration frequencies for each weather station. Thirty charts present isopleth analyses of seasonal and annual, and morning and afternoon normalized pollutant concentrations that were exceeded 10, 25, and 50 percent of the time for specified city sizes. The occurrence of episodes during which upper limits on mixing height and wind speed were not exceeded were determined from the daily morning and afternoon values of these parameters. Isopleths of the total number of episode-days for episodes lasting at least 2 days and at least 5 days with various limiting mixing-height and wind-speed values are presented in 20 charts.

The Urban Climate aims to summarize analytical studies directed toward physical understanding of the rural-urban differences in the atmospheric boundary layer. Attempts to quantify conditions have met with some success. There is certainly a clear understanding of the physical relations that create the climatic differences of urbanized areas. Although some of the earlier classical studies are cited here, the emphasis is on the work done during the last decade and a half. This volume comprises 11 chapters, beginning with an introductory chapter discussing the literature surrounding the topic, its historical development, and the problem of local climate modification. The second chapter presents an assessment of the urban atmosphere on a synoptic and local scale, and examines the observational procedures involved. The following chapters then go on to discuss urban air composition; urban energy fluxes; the urban heat island; the urban wind field; models of urban temperature and wind fields; moisture, clouds, and hydrometeors; urban hydrology; special aspects of urban climate; and finally, urban planning. This book will be of interest to practitioners in the fields of meteorology, urban planning, and urban climatology.