The Treatment of Relative Dispersion Within a Combined Puff-Particle Model (PPM)

  • Peter de Haan
  • Mathias W. Rotach
Part of the NATO • Challenges of Modern Society book series (NATS, volume 22)


The Puff-Particle Model (PPM) combines the advantages of both, puff and particle dispersion models. In short, in this approach the centre of mass of each puff is moved along a ‘particle trajectory’, so trying to mimic the quickly changing turbulent flow field. However, particle models account for dispersion of turbulent eddies of all sizes (1 -particle statistics, absolute dispersion) while puff models use relative dispersion to describe the puff growth. Therefore, on combining these two approaches as described above, the dispersing effect of small eddies (smaller than approximately the puff’s size) is accounted for twice. A method is therefore presented to correctly simulate the relative dispersion of puffs within the framework of the PPM. It is based on removing the effect of the high-frequency part of the spectrum when using a ‘particle trajectory’ as the trajectory of the puff centre. It is shown on the basis of tracer data, that the correct treatment and interpretation of the two contributions to the dispersion process is crucial for reproducing experimental results to a good correspondence.


Relative Dispersion Kalman Filter Particle Model Turbulent Velocity Tracer Experiment 
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  1. de Haan, P., and Rotach, M. W. (1995): ‘A puff-particle dispersion model’, Int. J. Environment and Pollution, 5, Nos. 4–6, 350–359.Google Scholar
  2. de Haan, P., and Rotach, M. W. (1997): ‘A novel approach to atmospheric dispersion modelling: the Puff-Particle Model (PPM)’, submitted to the Quarterly Journal of the Royal Meteorological Society. Google Scholar
  3. Gryning, S.-E., and Lyck, E. (1984): ‘Atmospheric Dispersion from Elevated Sources in an Urban Area: Comparisons between Tracer Experiments and Model Calculations’, J. Clim. Appl. Met., 23, 651–660.CrossRefGoogle Scholar
  4. Højstrup, J. (1981): ‘A Simple Model for the Adjustment of Velocity Spectra in Unstable Conditions Down-stream of an Abrupt Change in Roughness and Heat Flux’, Boundary-Layer Meteorol., 21, 341–356.CrossRefGoogle Scholar
  5. Højstrup, J. (1982): ‘Velocity spectra in the Unstable Planetary Boundary Layer’, J. Atmos. Sci., 39, 2239–2248.CrossRefGoogle Scholar
  6. Kaimal, J. C., Wyngaard, J. C., Coté, O. R. and Izumi, Y. (1972): ‘Spectral characteristics of surface layer turbulence’, Quart. J. Roy. Met. Soc., 98, 563–589.CrossRefGoogle Scholar
  7. Olesen, H. R., Larsen, S. E. and Højstrup, J. (1984): ‘Modelling velocity spectra in the lower part of the planetary boundary layer’, Boundary-Layer Meteorol., 29, 285–312.CrossRefGoogle Scholar
  8. Rotach, M. W., Gryning, S.-E. and Tassone, C. (1996): ‘A Two-Dimensional Stochastic Lagrangian Dispersion Model for Daytime Conditions’, Quart. J. Roy. Met. Soc., 122, 367–389.CrossRefGoogle Scholar
  9. Rotach, M. W. and de Haan, P. (1996): ‘On the Urban Aspect of the Copenhagen Data Set’, Pre-prints 4th Workshop on Harmonisation within Atm. Dispersion Models, May 5-9, Oostende, Belgium, 1996.Google Scholar
  10. Thomson, D. J. (1987): ‘Criteria for the Selection of Stochastic Models of Particle Trajectories in Turbulent Flows’, J. Fluid Mech., 180, 529–556.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1998

Authors and Affiliations

  • Peter de Haan
    • 1
  • Mathias W. Rotach
    • 1
  1. 1.Swiss Federal Institute of TechnologyZurichSwitzerland

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