You need JavaScript to view this

Atmospheric diffusion of large clouds

Abstract

Clouds of pollutants travel within a coordinate system that is fixed to the earth's surface, and they diffuse and grow within a coordinate system fixed to the cloud's center. This paper discusses an approach to predicting the cloud's properties, within the latter coordinate system, on space scales of a few hundred meters to a few hundred kilometers and for time periods of a few days. A numerical cloud diffusion model is presented which starts with a cloud placed arbitrarily within the troposphere. Similarity theories of atmospheric turbulence are used to predict the horizontal diffusivity as a function of initial cloud size, turbulent atmospheric dissipation, and time. Vertical diffusivity is input as a function of time and height. Therefore, diurnal variations of turbulent diffusion in the boundary layer and effects of temperature inversions, etc. can be modeled. Nondiffusive cloud depletion mechanisms, such as dry deposition, washout, and radioactive decay, are also a part of this numerical model. An effluent cloud, produced by a reactor run at the Nuclear Rocket Development Station, Nevada, is discussed in this paper. Measurements on this cloud, for a period of two days, are compared to calculations with the above numerical cloud diffusion model. In general, there  More>>
Authors:
Crawford, T. V. [1] 
  1. Univ. of California, Lawrence Radiation Lab., Livermore, California (United States)
Publication Date:
Jul 01, 1967
Product Type:
Conference
Report Number:
AECL-2787
Resource Relation:
Conference: USAEC Meteorological Information Meeting, Chalk River, Ontario (Canada), 11-14 Sep 1967; Other Information: 10 refs., 13 figs.; Related Information: In: Proceedings of the USAEC Meteorological Information Meeting| by Mawson, C.A. (ed.)| 630 p.
Subject:
54 ENVIRONMENTAL SCIENCES; CLOUDS; DIFFUSION; NUMERICAL ANALYSIS; POLLUTANTS; TROPOSPHERE; TURBULENCE
OSTI ID:
22141898
Research Organizations:
Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)
Country of Origin:
Canada
Language:
English
Other Identifying Numbers:
TRN: CA1300235096499
Availability:
Available from INIS in electronic form
Submitting Site:
CANN
Size:
page(s) 191-214
Announcement Date:
Oct 24, 2013

Citation Formats

Crawford, T. V. Atmospheric diffusion of large clouds. Canada: N. p., 1967. Web.
Crawford, T. V. Atmospheric diffusion of large clouds. Canada.
Crawford, T. V. 1967. "Atmospheric diffusion of large clouds." Canada.
@misc{etde_22141898,
title = {Atmospheric diffusion of large clouds}
author = {Crawford, T. V.}
abstractNote = {Clouds of pollutants travel within a coordinate system that is fixed to the earth's surface, and they diffuse and grow within a coordinate system fixed to the cloud's center. This paper discusses an approach to predicting the cloud's properties, within the latter coordinate system, on space scales of a few hundred meters to a few hundred kilometers and for time periods of a few days. A numerical cloud diffusion model is presented which starts with a cloud placed arbitrarily within the troposphere. Similarity theories of atmospheric turbulence are used to predict the horizontal diffusivity as a function of initial cloud size, turbulent atmospheric dissipation, and time. Vertical diffusivity is input as a function of time and height. Therefore, diurnal variations of turbulent diffusion in the boundary layer and effects of temperature inversions, etc. can be modeled. Nondiffusive cloud depletion mechanisms, such as dry deposition, washout, and radioactive decay, are also a part of this numerical model. An effluent cloud, produced by a reactor run at the Nuclear Rocket Development Station, Nevada, is discussed in this paper. Measurements on this cloud, for a period of two days, are compared to calculations with the above numerical cloud diffusion model. In general, there is agreement. within a factor of two, for airborne concentrations, cloud horizontal area, surface air concentrations, and dry deposition as airborne concentration decreased by seven orders of magnitude during the two-day period. (author)}
place = {Canada}
year = {1967}
month = {Jul}
}