Boundary-Layer Meteorology

, Volume 54, Issue 4, pp 387–410 | Cite as

Estimation of areally-averaged surface fluxes

  • Martin Claussen


The concept of blending height is used to estimate areally averaged surface fluxes of momentum and heat in a stratified, horizontally inhomogeneous surface-layer flow. This concept is based on the assumption that at sufficiently large heights above a heterogeneous surface, subsequent surface modifications will not be recognizable in the flow individually, but overall flux and mean profiles will represent the surface condition of a large area. The height at which the flow becomes approximately independent of horizontal position is called blending height according to Wieringa (1986).

Here, it is proposed to classify the ground surface in a surface-layer grid box of a larger-scale model into several land-use categories. Surface momentum and heat fluxes should be estimated for each category at the blending height. The grid-averaged surface fluxes are to be obtained by the average of surface fluxes on each land-use surface weighted by its fractional area. The postulate of computing the surface fluxes at the blending height leads to a new formulation of turbulent transfer coefficients.

The proposed parameterization has been tested by employing a small-scale numerical model as a surface-layer grid box of a hypothesized larger-scale model. Several quite different flow configurations have been studied in order to investigate the performance of the new parameterization. Generally, the relative errors of estimated averaged surface fluxes are found to be well within ±10%.


Heat Flux Transfer Coefficient Surface Modification Ground Surface Fractional Area 
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  1. Anderson, D. A., Tannehill, J. C., and Pletcher, R. H.: 1984, Computational Fluid Mechanics and Heat Transfer, McGraw Hill Book Company, New York, 599pp.Google Scholar
  2. Beljaars, A. C. M., Schotanus, P., and Nieuwstadt, F. T. M.: 1983. ‘Surface Layer Similarity Under Nonuniform Fetch Conditions’, J. Climate App. Meteorol. 22, 1800–1810.Google Scholar
  3. Brutsaert, W.: 1979, ‘Heat and Mass Transfer to and from Surfaces with Dense Vegetation or Similar Permeable Roughness’, Boundary-Layer Meteorol. 16, 365–388.Google Scholar
  4. Claussen, M.: 1987, ‘The Flow in a Turbulent Boundary Layer Upstream of a Change in Surface Roughness’, Boundary-Layer Meteorol. 40, 31–86.Google Scholar
  5. Claussen, M.: 1988a, ‘Models of Eddy Viscosity for Numerical Simulation of Horizontally Inhomogeneous Surface Layer Flow’, Boundary-Layer Meteorol. 42, 337–369.Google Scholar
  6. Claussen, M.: 1988b, ‘On the Surface Energy Budget of Coastal Zones with Tidal Flats’, Beitr. Phys. Atmosph. 61, 39–49.Google Scholar
  7. Claussen, M.: 1989. ‘Subgrid-Scale Fluxes and Flux Divergences in a Neutrally Stratified, Horizontally Inhomogeneous Surface-Layer’, Beitr. Phys. Atmosph. 62, 236–245.Google Scholar
  8. Claussen, M.: 1990, ‘Area-Averaging of Surface Fluxes in a Neutrally Stratified, Horizontally Inhomogeneous Atmospheric Boundary Layer’, Atmos. Environ. 24A, 1349–1360.Google Scholar
  9. Claussen M.: 1991. ‘Local Advection Processes in the Surface Layer of the Marginal Ice Zone’, Boundary-Layer Meteorol. 54, in press.Google Scholar
  10. Deardorff, J. W.: 1978, ‘Efficient Prediction of Ground Surface Temperature and Moisture with Inclusion of a Layer of Vegetation’, Jour. Geophys. Res. 83, 1889–1903.Google Scholar
  11. Dolman, A. J.: 1987, ‘Predicting Evaporation from an Oak Forest’, Ph.D. thesis. Rijk-suniversiteit te Groningen. 91 pp.Google Scholar
  12. Dyer, A. J.: 1974, ‘A Review of Flux-Profile Relationships’, Boundary-Layer Meteorol. 7, 363–372.Google Scholar
  13. Hicks, B. B.: 1985, ‘Application of Forest-Atmosphere Turbulent Exchange Information’, The Forest- Atmosphere Interaction, D. Reidel Publishing Company, Dordrecht, pp. 631–644.Google Scholar
  14. Hinze, H. O.: 1975, Turbulence. McGraw-Hill Book Comp., New York, 790pp.Google Scholar
  15. Lettau, H. H.: 1979, ‘Wind and Temperature Profile Prediction for Diabatic Surface Layers Including Strong Inversion Cases’, Boundary-Layer Meteorol. 17, 443–464.Google Scholar
  16. Louis, J. F.: 1979. ‘A Parametric Model of Vertical Eddy Fluxes in the Atmosphere’, Boundary-Layer Meteorol. 102, 924–933.Google Scholar
  17. Mahrt, L.: 1987, ‘Grid-Averaged Surface Fluxes’, Mon. Wea. Rev. 15, 1550–1560.Google Scholar
  18. Mason, P. J.: 1988, ‘The Formation of Areally-Averaged Roughness Lengths’, Quart. J. R. Meteorol. Soc. 114, 399–420.Google Scholar
  19. Taylor, P. A.: 1969, ‘The Planetary Boundary Layer above a Change in Surface Roughness’, J. Atmos. Sci. 26, 432–440.Google Scholar
  20. Wieringa, J.: 1986, ‘Roughness-Dependent Geographical Interpolation of Surface Wind Speed Averages’, Quart. J. R. Meteorol. Soc. 112, 867–889.Google Scholar
  21. Wood, N. and Mason, P. J.: 1990, ‘The Influence of Stability on Effective Roughness Lengths’, Proc. of the 9th Symposium on Turbulence and Diffusion held in Roskilde, April 30th–May 3rd, 1990, pp. 247–249.Google Scholar

Copyright information

© Kluwer Academic Publishers 1991

Authors and Affiliations

  • Martin Claussen
    • 1
  1. 1.Forschungszentrum GeesthachtGeesthachtFed. Rep. Germany

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