pure and applied geophysics

, Volume 77, Issue 1, pp 61–67 | Cite as

The effects of surface absorption and terminal velocity on the atmospheric diffusion of particulate material

  • Chung-Muh Tang


A two-dimensional diffusion model in the vertical plane is considered as an unsteady boundary value problem which is solved by applying Laplace transformation and finding Green's function. The effects of the surface (ground) absorption (measured by β) and the terminal velocity (w) present an alternative explanation other than considering the variable eddy diffusivities and the change of the wind with height.

It is shown that the effect of the surface absorption acts opposite to the effect of the terminal velocity for the diffusion of a source placed at the surface. The former alone reduces the concentration with the distance in the downwind direction at a faster rate than the latter alone.

The path of the plume is considered only for the casew=2 β. The effects of suchw and β only slightly modify the path of the plume without such effects. If the height of the source is short, say 20 m, the modification of the path of the plume is insignificant compared to that of the case with the source placed at the surface.


Alternative Explanation Fast Rate Diffusion Model Surface Absorption Vertical Plane 
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    Kenneth L. Calder,Atmospheric diffusion of particulate material, considered as a boundary value problem. J. Meteorol.18 (1961), 413–415.Google Scholar
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    Erdélyi, Magnus, Oberhettinger andTricomi,Tables of integral transforms, Bateman Manuscript Project, C.I.T., Vol. 2 (McGraw-Hill, 1954).Google Scholar
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    A. S. Monin,On the boundary condition on the earth surface for diffusion pollution, Advances in Geophysics6 (1956), 435–436.Google Scholar

Copyright information

© Birkhäuser Verlag 1969

Authors and Affiliations

  • Chung-Muh Tang
    • 1
  1. 1.Department of MeteorologyUniversity of CaliforniaLos AngelesUSA

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