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Boundary-Layer Meteorology

, Volume 65, Issue 1–2, pp 111–136 | Cite as

The vertical profile of concentration fluctuations in near-surface plumes

  • Kenneth R. Mylne
Article

Abstract

Field experiments on concentration fluctuations have frequently measured horizontal cross-sections of fluctuation statistics through plumes at fixed heights “near the surface”, but have not considered the effect of height above the ground in any detail. A set of tracer experiments designed to measure vertical profiles of concentration fluctuations in plumes, with a range of source heights, is described, and profiles of statistics are presented. Considerable variation of the statistics with both source and detector height is found. Near the surface, fluctuation intensity is a minimum and the time and length scales of the fluctuations are greatly increased. Profiles are consistent with the idea that concentration fluctuations near the surface are like those higher up at a greater distance from the source. Lowering the source height reduces the fluctuation intensity at all heights, and also alters the form of the concentration PDF. Results may be explained by the reduced length scale of sheargenerated turbulence near the surface causing enhanced small-scale mixing, which rapidly smooths out much of the fine structure with the plume.

Keywords

Field Experiment Fine Structure Vertical Profile Great Distance Fluctuation Intensity 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Bara, B. M., Wilson, D. J. and Zelt, B. W. 1992, ‘Concentration Fluctuation Profiles from a Water Channel Simulation of a Ground-Level Release’,Atmos. Env. 26A, 1053–1062.Google Scholar
  2. Chen, F. and Schwerdtfeger, P.: 1989, ‘Flux-gradient Relationships for Momentum and Heat over a Rough Natural Surface’,Quart. J. Roy. Meteorol. Soc. 115, 335–352.Google Scholar
  3. Dinar, N., Kaplan, H. and Kleiman, M.: 1988, ‘Characterization of Concentration Fluctuations of a Surface Plume in a Neutral Boundary Layer’,Boundary-layer Meteorol. 45, 157–175.Google Scholar
  4. Fackrell, J. E. and Robins, A. G.: 1982, ‘Concentration Fluctuations and Fluxes in Plumes from Point Sources in a Turbulent Boundary Layer’,J. Fluid Mech. 117, 1–26.Google Scholar
  5. Hanna, S. R.: 1984, ‘The Exponential Probability Density Function and Concentration Fluctuations in Smoke Plumes’,Boundary Layer Meteorol. 29, 361–375.Google Scholar
  6. Hanna, S. R.: 1984, ‘The Exponential Probability Density Function and Concentration Fluctuations in Smoke Plumes’,Boundary Layer Meteorol. 29, 361–375.Google Scholar
  7. Hojstrup, J.: 1982, ‘Velocity Spectra in the Unstable Planetary Boundary Layer’,J. Atmos. Sci. 39, 2239–2248.Google Scholar
  8. Lewellen, W. S. and Sykes, R. I. (1986) ‘Analysis of Concentration Fluctuations from Lidar Observations of Atmospheric Plumes’,J. Climate Appl. Meteorol. 25, 1145–1154.Google Scholar
  9. Mylne, K. R.: 1992, ‘Concentration Fluctuation Measurements in a Plume Dispersing in a Stable Surface Layer’,Boundary Layer Meteorol. 60, 15–48.Google Scholar
  10. Mylne, K. R. and Davidson, M. J.: 1991, ‘Concentration Fluctuation Experiments in Stable Conditions and in a Pseudo-Urban Environment’,19th International Technical Meeting on Air Pollution Modelling and its Application, Ierapetra, Crete, 479–486. To be published inAir Pollution Modeling and Its Application IX, ed., Han van Dop, Plenum Press, New York.Google Scholar
  11. Mylne, K. R. and Mason, P. J.: 1991, ‘Concentration Fluctuation Measurements in a Dispersing Plume at a Range of up to 1000 m’,Quart. J. Roy. Meteorol. Soc. 117, 177–206.Google Scholar
  12. Pasquill, F. and Smith, F. B., 1983,Atmospheric Diffusion, third edition, Ellis Horwood, Chichester.Google Scholar
  13. Peterson, H. G., Lamb, B. K. and Stock, D. E.: 1988, ‘Plume Concentration and Velocity Fluctuations During Convective and Stable Conditions’,8th Symp. on Turb. and Diff. Am. Meteorol. Soc. 341–344.Google Scholar
  14. Sawford, B. L.: 1987, ‘Conditional Concentration Statistics for Surface Plumes in the Atmospheric Boundary Layer’,Boundary Layer Meteorol. 38, 209–223.Google Scholar
  15. Thomson, D. J.: 1990, ‘A Stochastic Model for the Motion of Particle Pairs in Isotropic High Reynolds Number Turbulence, and its Application to the Problem of Concentration Variance’,J. Fluid Mech. 210, 113–153.Google Scholar

Copyright information

© Kluwer Academic Publishers 1993

Authors and Affiliations

  • Kenneth R. Mylne
    • 1
  1. 1.Meteorological OfficeBracknellUK

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