The Study of the Diffusion of Gases Or Aerosols in the Lower Atmosphere PDF Download
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Author: H. E. Cramer
Publisher:
ISBN:
Category : Atmospheric diffusion
Languages : en
Pages : 312
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Book Description
The principal objectives of the research described in this report have been to achieve improved understanding of the basic physical processes involved in the dispersal of airborne material in the lower atmosphere; and, to establish empirical relationships between basic diffusion parameters and direct meteorological indicators that permit satisfactory quantitative estimates of dispersal from continuous point sources, over travel distances of the order of 1 km, in a wide variety of general weather conditions. These objectives have been achieved largely as the result of a series of comprehensive field observations involving simultaneous measurements both of diffusion and the structure of atmospheric turbulence. The diffusion measurements comprise 10-min average concentrations of sulfur-dioxide gas emitted from a continuous point source near ground level, at travel distances from 50 to 800 m from the release-point for the tracer. The meteorological observations include mean wind speeds, frequency distributions of azimuth oLnd direction, vertical profiles of wind speed and air temperature, and measurements of the fluctuations in wind velocity obtained from bivanes and heatedthermocouple anemometers. Over one hundred individual experiments of this type were carried out at Round Hill and at a field site near O'Neill, Nebraska during Project Prairie Grass, an extensive series of diffusion measurements sponsored by the Air Force Cambridge Research Center during the summer of 1956. These data comprise the most comprehensive set of small-scale diffusion and meteorological observations currently available. They provide a fairly complete picture of the probable variations in basic diffusion parameters over travel distances of the order of 1 km in all conditions of thermal stratification ...
Author: H. E. Cramer
Publisher:
ISBN:
Category : Atmospheric diffusion
Languages : en
Pages : 312
Get Book Here
Book Description
The principal objectives of the research described in this report have been to achieve improved understanding of the basic physical processes involved in the dispersal of airborne material in the lower atmosphere; and, to establish empirical relationships between basic diffusion parameters and direct meteorological indicators that permit satisfactory quantitative estimates of dispersal from continuous point sources, over travel distances of the order of 1 km, in a wide variety of general weather conditions. These objectives have been achieved largely as the result of a series of comprehensive field observations involving simultaneous measurements both of diffusion and the structure of atmospheric turbulence. The diffusion measurements comprise 10-min average concentrations of sulfur-dioxide gas emitted from a continuous point source near ground level, at travel distances from 50 to 800 m from the release-point for the tracer. The meteorological observations include mean wind speeds, frequency distributions of azimuth oLnd direction, vertical profiles of wind speed and air temperature, and measurements of the fluctuations in wind velocity obtained from bivanes and heatedthermocouple anemometers. Over one hundred individual experiments of this type were carried out at Round Hill and at a field site near O'Neill, Nebraska during Project Prairie Grass, an extensive series of diffusion measurements sponsored by the Air Force Cambridge Research Center during the summer of 1956. These data comprise the most comprehensive set of small-scale diffusion and meteorological observations currently available. They provide a fairly complete picture of the probable variations in basic diffusion parameters over travel distances of the order of 1 km in all conditions of thermal stratification ...
Author: H. E. Cramer
Publisher:
ISBN:
Category : Atmospheric diffusion
Languages : en
Pages : 33
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Book Description
The research described in this report deals with two aspects of the research program initiated under the preceding Air Force contract that had not been brought to a stage of completion. Past field studies of small-scale diffusion processes provided comprehensive information on the structure of gas plumes from a continuous point source located near ground level, over travel distances of the order of 1 km, for sampling times from 0.5 to 10 min. Additional concentration measurements of this type for extremely short sampling times of the order of 1 sec were clearly required to round out existing knowledge of the probable variations in basic diffusion parameters with sampling time. Minor changes in the sulfur-dioxide technique used in previous experiments permitted adaptation of existing diffusion equipment to measurements of concentration at travel distances from 50 to 300 m over 3-sec sampling times. Fourteen experiments utilizing this modified technique were conducted during the fall of 1958. Meteorological observations obtained in connection with these diffusion experiments included: mean wind speeds and frequency distributions of azimuth wind direction; vertical profiles of mean wind speed and air temperature; and, measurements of the fluctuations in wind velocity indicated by lightweight bivanes equipped with heated-thermocouple anemometers. Analysis of the diffusion data provides valuable insight into the characteristic features of the "instantaneous" plume structure associated with continuous effluent emission from a point source. Peak concentrations for the 3-sec sampling intervals are, on the average, about three times larger than corresponding 10-min concentrations; in the extreme, this difference may be one order of magnitude. Average plume widths or standard deviations of crossplume concentration for the 3-sec intervals are about one-third of the 10-min values; in the extreme, the 3-sec plume widths are from five to ten times smaller than the 10-min widths. The results also show that the average distance dependence of the 3-sec diffusion parameters is closely similar to that previously established for the 10-min plumes in near-neutral stratification. Three-second peak concentrations, for example, tend to be inversely proportional to the square of the distance. Complete summaries of the raw experimental data for the diffusion measurements and the slow-response meteorological observations are presented in the Appendix to this report ...
Author: Glenn R. Hilst
Publisher:
ISBN:
Category :
Languages : en
Pages : 242
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Book Description
Diffusion of aerosols over an urban complex was measured and analyzed in 21 separate experimental events. Fluorescent pigment powders were released as a quasi-instantaneous elevated line source upwind of Fort Wayne, Indiana; their distribution was measured in and above urban and rural. A mathematical model was derived. The test results identified these features of atmospheric motions in and around an isolated city: (1) when the lower (61 m) atmosphere is stable (temperature lapse rate between dry adiabatic and isothermal) the axis of the tracer cloud descends rather quickly to ground level. When temperature lapse rate is clearly positive (inversion) the tracer cloud remained about release height and slowly diffused vertically. Under unstable conditions vertical mixing is vigorous; the tracer cloud is uniformly mixed from the ground to above the vertical sampling array. (2) The enhanced surface roughness and the thermal mixing caused by the city produce an average 30 to 50 per cent more vertical mixing over the city than the rural area: increased vertical mixing causes more uniform particle dispersion. (3) Individual measurements within the city, randomly variable at a factor of about 2 and with no identifiable preferred regions of high or low dosage, imply that Ft. Wayne exemplifies a single surface anomaly for the purpose of predicting its effect on aerosol diffusion. (4) Total variability of surface dosage ranges from 0 to about 1000 units, defined as above.
Author: Edward J. Lehmann
Publisher:
ISBN:
Category : Air
Languages : en
Pages : 162
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Book Description
The cited reports cover Federally-funded research on the use of tracers to study lower atmospheric air pollution movements. The tracers used include sulfur hexafluoride, krypton 85, carbon 14, and other radioactive isotopes. The studies cite the results and techniques used, tracer movement from nuclear power plants, industrial stacks, urban areas, and the detectors used in their measurement. (Contains 55 abstracts).
Author: Daniel J. Jacob
Publisher: Princeton University Press
ISBN: 0691001855
Category : Nature
Languages : en
Pages : 280
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Book Description
Atmospheric chemistry is one of the fastest growing fields in the earth sciences. Until now, however, there has been no book designed to help students capture the essence of the subject in a brief course of study. Daniel Jacob, a leading researcher and teacher in the field, addresses that problem by presenting the first textbook on atmospheric chemistry for a one-semester course. Based on the approach he developed in his class at Harvard, Jacob introduces students in clear and concise chapters to the fundamentals as well as the latest ideas and findings in the field. Jacob's aim is to show students how to use basic principles of physics and chemistry to describe a complex system such as the atmosphere. He also seeks to give students an overview of the current state of research and the work that led to this point. Jacob begins with atmospheric structure, design of simple models, atmospheric transport, and the continuity equation, and continues with geochemical cycles, the greenhouse effect, aerosols, stratospheric ozone, the oxidizing power of the atmosphere, smog, and acid rain. Each chapter concludes with a problem set based on recent scientific literature. This is a novel approach to problem-set writing, and one that successfully introduces students to the prevailing issues. This is a major contribution to a growing area of study and will be welcomed enthusiastically by students and teachers alike.
Author: Ian Colbeck
Publisher: John Wiley & Sons
ISBN: 1119977924
Category : Science
Languages : en
Pages : 522
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Book Description
AEROSOL SCIENCE TECHNOLOGY AND APPLICATIONS Aerosols influence many areas of our daily life. They are at the core of environmental problems such as global warming, photochemical smog and poor air quality. They can also have diverse effects on human health, where exposure occurs in both outdoor and indoor environments. However, aerosols can have beneficial effects too; the delivery of drugs to the lungs, the delivery of fuels for combustion and the production of nanomaterials all rely on aerosols. Advances in particle measurement technologies have made it possible to take advantage of rapid changes in both particle size and concentration. Likewise, aerosols can now be produced in a controlled fashion. Reviewing many technological applications together with the current scientific status of aerosol modelling and measurements, this book includes: Satellite aerosol remote sensing The effects of aerosols on climate change Air pollution and health Pharmaceutical aerosols and pulmonary drug delivery Bioaerosols and hospital infections Particle emissions from vehicles The safety of emerging nanomaterials Radioactive aerosols: tracers of atmospheric processes With the importance of this topic brought to the public's attention after the eruption of the Icelandic volcano Eyjafjallajökull, this book provides a timely, concise and accessible overview of the many facets of aerosol science.
Author: Claudio Tomasi
Publisher: John Wiley & Sons
ISBN: 3527336451
Category : Science
Languages : en
Pages : 706
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Book Description
Ein Blick auf die morphologischen, physikalischen und chemischen Eigenschaften von Aerosolen aus den unterschiedlichsten natürlichen und anthropogenen Quellen trägt zum besseren Verständnis der Rolle bei, die Aerosolpartikel bei der Streuung und Absorption kurz- und langwelliger Strahlung spielen. Dieses Fachbuch bietet Informationen, die sonst schwer zu finden sind, und vermittelt ausführlich die Kenntnisse, die erforderlich sind, um die mikrophysikalischen, chemischen und Strahlungsparameter zu charakterisieren, die bei der Wechselwirkung von Sonnen- und Erdstrahlen so überaus wichtig sind. Besonderes Augenmerk liegt auf den indirekten Auswirkungen von Aerosolen auf das Klima im Rahmen des komplexen Systems aus Aerosolen, Wolken und der Atmosphäre. Auch geht es vorrangig um die Wirkungen natürlicher und anthropogener Aerosole auf die Luftqualität und die Umwelt, auf die menschliche Gesundheit und unser kulturelles Erbe. Mit einem durchgängig lösungsorientierten Ansatz werden nicht nur die Probleme und Gefahren dieser Aerosole behandelt, sondern auch praktikable Lösungswege aufgezeigt.
Author: Daniel J. Basta
Publisher: Routledge
ISBN: 1317368711
Category : Nature
Languages : en
Pages : 569
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Book Description
This report was undertaken on local, regional, state and federal levels in the United States to analyse the impact residuals have on environmental quality and to emphasise the need for Residuals- Environmental quality management (REQM). Originally published in 1982, this study brings together information on approaches for analysing natural systems and which factors to consider when choosing an approach. This title will be of interest to students of environmental studies as well as professionals and policy makers.
Author: Peter S. Liss
Publisher: Springer
ISBN: 3642256430
Category : Science
Languages : en
Pages : 315
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Book Description
The oceans and atmosphere interact through various processes, including the transfer of momentum, heat, gases and particles. In this book leading international experts come together to provide a state-of-the-art account of these exchanges and their role in the Earth-system, with particular focus on gases and particles. Chapters in the book cover: i) the ocean-atmosphere exchange of short-lived trace gases; ii) mechanisms and models of interfacial exchange (including transfer velocity parameterisations); iii) ocean-atmosphere exchange of the greenhouse gases carbon dioxide, methane and nitrous oxide; iv) ocean atmosphere exchange of particles and v) current and future data collection and synthesis efforts. The scope of the book extends to the biogeochemical responses to emitted / deposited material and interactions and feedbacks in the wider Earth-system context. This work constitutes a highly detailed synthesis and reference; of interest to higher-level university students (Masters, PhD) and researchers in ocean-atmosphere interactions and related fields (Earth-system science, marine / atmospheric biogeochemistry / climate). Production of this book was supported and funded by the EU COST Action 735 and coordinated by the International SOLAS (Surface Ocean- Lower Atmosphere Study) project office.
Author: Panel on Aerosol Radiative Forcing and Climate Change
Publisher: National Academies Press
ISBN: 0309588871
Category : Science
Languages : en
Pages : 180
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Book Description
This book recommends the initiation of an "integrated" research program to study the role of aerosols in the predicted global climate change. Current understanding suggest that, even now, aerosols, primarily from anthropogenic sources, may be reducing the rate of warming caused by greenhouse gas emissions. In addition to specific research recommendations, this book forcefully argues for two kinds of research program integration: integration of the individual laboratory, field, and theoretical research activities and an integrated management structure that involves all of the concerned federal agencies.
