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OLS Field Name OLS Field Data
Main Title Simple PDF (Probability Distribution Function) Models for Convectively Driven Vertical Diffusion.
Author Zong-Kai, L. ; Briggs, G. A. ;
CORP Author Environmental Protection Agency, Research Triangle Park, NC. Atmospheric Sciences Research Lab. ;Nanjing Univ. (China). Dept. of Atmospheric Sciences.
Publisher c1988
Year Published 1988
Report Number EPA/600/J-88/329;
Stock Number PB89-206692
Additional Subjects Probability distribution functions ; Mathematical models ; Atmospheric diffusion ; Boundary layer ; Wind velocity ; Convection ; Heat transfer ; Turbulent flow ; Aerial surveys ; Optical radar ; Comparison ; Reprints ; Gaussian plume models ; Tracer studies
Holdings
Library Call Number Additional Info Location Last
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Status
NTIS  PB89-206692 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. 12/18/1989
Collation 22p
Abstract
The mode of vertical velocity in convective boundary layers is usually negative and the probability distribution function (PDF) of w, P(sub w), is rarely symmetric. Consequently, vertical diffusion from elevated sources is usually asymmetric and exhibits a descending mode of concentration, causing higher peak surface concentrations than predicted by Gaussian models. The main concentration (X) effects, the authors argue, can be modeled using simple PDF diffusion models, with tracers responding to P(sub w) at the source height with straight line trajectories and simple reflection at the surface and z(sub i), the mixing depth. The critical element is the choice of P(sub w). The PDF models are compared with diverse selection of atmospheric turbulence measurements. Recent lidar measurements of oil fog plumes are presented that show a large variability.