Boundary-Layer Meteorology

, Volume 83, Issue 3, pp 407–421

AN ANALYTICAL ONE-DIMENSIONAL MODEL OF MOMENTUM TRANSFER BY VEGETATION OF ARBITRARY STRUCTURE

  • W. J. MASSMAN
Article

Abstract

An analyticalone-dimensional model of momentum transferby vegetation with variable foliage distribution,sheltering and drag coefficientis developed. The model relies on a simpleparameterization of the ratio of theabove-canopy friction velocity, u*, to thewind speed at the top of the canopy,u(h), to predict vegetation roughness length(z0) and displacement height(d) as functions of canopy height (h) and dragarea index. Model predictionsof d/h and z/h compare very favorably withobserved values.A model sensitivity analysis suggests that shelteringeffects for momentum transfertend to make canopies with non-uniform foliagedistribution resemble canopies withmore uniform foliage distribution and that anyinfluence wind speed has on d/hand z0/h is more likely to be related to theinfluence that wind speed may haveon u*/u(h) rather than the influence windspeed may have on the foliage dragcoefficient. Model results indicate that z0/hand d/h are sensitive to uncertaintiesin the numerical values of the model parameters,foliage density and distribution,sheltering effects and variations in drag coefficientwithin the canopy. In additionz0/h is also shown to be sensitive to thepresence or absence of the roughnesssublayer. Given the simplicity of the model it issuggested that it may be of usefor land surface parameterizations in large scalemodels.

Momentum transfer by vegetation Vegetation roughness length Vegetation displacement height Variable foliage distribution 

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References

  1. Albini, F. A.: 1981, 'A Phenomenological Model for Wind Speed and Shear Stress Profiles in Vegetation Cover Layers', J. Appl. Meteorol. 20, 1325–1335.Google Scholar
  2. Bache, D. H.: 1986, 'Momentum Transfer to Plant Canopies: Influence of Structure and Variable Drag', Atmos. Environ. 20, 1369–1378.Google Scholar
  3. Bache, D. H. and Unsworth, M. H.: 1977, 'Some Aerodynamic Features of a Cotton Canopy', Quart. J. Roy. Meteorol. Soc. 103, 121–134.Google Scholar
  4. Grant, R. H.: 1984, 'The Mutual Interference of Spruce Canopy Structural Elements', Agric. For. Meteorol. 32, 145–156.Google Scholar
  5. Jarvis, P. G., James, G. B., and Landsberg, J. J.: 1976, 'Coniferous Forest', in J. L. Monteith (ed.), Vegetation and the Atmosphere, Vol. 2, Academic Press, London, pp. 171–240.Google Scholar
  6. Kondo, J. and Akashi, S.: 1976, 'Numerical Studies of the Two-dimensional Flow in Horizontally Homogeneous Canopy Layers', Boundary-Layer Meteorol. 10, 255–272.Google Scholar
  7. Kondo, J. and Kawanaka, A.: 1986, 'Numerical Study of the Bulk Heat Transfer Coefficient for a Variety of Vegetation Types and Densities', Boundary-Layer Meteorol. 37, 285–296.Google Scholar
  8. Landsberg, J. J. and Powell, D. B. B.: 1973, 'Surface Exchange Characteristics of Leaves Subject to Mutual Interference', Agric. Meteorol. 12, 169–184.Google Scholar
  9. Massman, W. J.: 1982, 'Foliage Distribution in Old-growth Coniferous Tree Canopies',Can. J. Forest Res. 12, 10–17.Google Scholar
  10. Massman, W. J.: 1987, 'A Comparative Study of Some Mathematical Models of MeanWind Structure and Aerodynamic Drag of Plant Canopies', Boundary-Layer Meteorol. 40, 179–197.Google Scholar
  11. Raupach, M. R.: 1994, 'Simplified Expressions for Vegetation Roughness Length and Zero-Plane Displacement as Functions of Canopy Height and Area Index', Boundary-Layer Meteorol. 71, 211–216.Google Scholar
  12. Raupach, M.R.: 1995, 'CORRIGENDA', Boundary-Layer Meteorol. 76, 303–304.Google Scholar
  13. Rauner, J. L.: 1976, 'Deciduous Forests', in J. L. Monteith (ed.), Vegetation and the Atmosphere, Vol. 2, Academic Press, London, pp. 241–264.Google Scholar
  14. Schuepp, P. H.: 1989, 'Microstructure, Density and Wetness Effects on Dry Deposition to Foliage', Agric. For. Meteorol. 47, 179–198.Google Scholar
  15. Shaw, R. H. and Pereira, A. R.: 1982, 'Aerodynamic Roughness of a Plant Canopy: A Numerical Experiment', Agric. Meteorol. 26, 51–65.Google Scholar
  16. Seginer, I.: 1974, 'Aerodynamic Roughness of Vegetated Surfaces', Boundary-Layer Meteorol. 5, 383–393.Google Scholar
  17. Thom, A. S.: 1971, 'Momentum Absorption by Vegetation', Quart. J. Roy. Meteorol. Soc. 97, 414–428.Google Scholar
  18. Uchijima, Z.: 1976, 'Maize and Rice', in J. L. Monteith (ed.), Vegetation and the Atmosphere, Vol. 2, Academic Press, London, pp. 33–64.Google Scholar

Copyright information

© Kluwer Academic Publishers 1997

Authors and Affiliations

  • W. J. MASSMAN
    • 1
  1. 1.USDA/Forest Service, Rocky Mountain StationFort CollinsU.S.A

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