Non-dimensional wind and temperature profiles in the atmospheric surface layer: A re-evaluation
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Previous results of non-dimensional wind and temperature profiles as functions of ζ( = z/L) show systematic deviations between different experiments. These discrepancies are generally believed not to reflect real differences but rather instrumental shortcomings. In particular, it is clear that flow distortion has not been adequately treated in most previous experiments. In the present paper, results are presented from a surface-layer field experiment where great care was taken to remove any effects from this kind of error and also to minimize other measuring errors. Data from about 90 30-min runs with turbulence measurements at three levels (3, 6, and 14 m) and simultaneous profile data have been analysed to yield information on flux-gradient relationships for wind and temperature.
The flux measurements themselves show that the fluxes of momentum and sensible heat are constant within ± 7% on average for the entire 14 m layer in daytime conditions and when the stratification is slightly stable. For more stable conditions, the flux starts to decrease systematically somewhere in the layer 6 to 14 m. From a large body of data for near-neutral conditions (¦ζ¦ ≦ 0.1), values are derived for von Kármán's constant: 0.40 ± 0.01 and for Φ h at neutrally, 0.95 ± 0.04. The range of uncertainty indicated here is meant to include statistical uncertainty as well as the effect of possible systematic errors.
Data for Φ m and Φ h for an extended stability range (1 > ζ > − 3) are presented. Several formulas for Φ m and Φ h appearing in the literature have been used in a comparative study. But first all the formulas have been modified in accordance with the following assumptions: κ = 0.40 and (Φ h )ζ = 0 = 0.95; deviations from this result in the various studies are due to incomplete correction for flow distortion. After new corrections are introduced, the various formulas were compared with the present measurements and with each other. It is found that after this modification, the most generally used formulas for Φ m and Φ h for unstable conditions, i.e., those of Businger et al. (1971) and Dyer (1974) agree with each other to within ± 10% and with the present data. For stable conditions, the various formulas still disagree to some extent. The conclusion in relation to the present data is not as clear as for the unstable runs, because of increased scatter. It is, however, found that the modified curve of Businger et al. (1971) for Φ h fits the data well, whereas for Φ m , Dyer's (1974) curve appears to give slightly better agreement.
KeywordsStratification Temperature Profile Statistical Uncertainty Unstable Condition Flux Measurement
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- Baldocchi, D. D., Verma, S. B., and Rosenberg, N. J.: 1983, ‘Characteristics of Air Flow Above and Within Soybean Canopies’, Boundary-Layer Meteorol. 25, 43–54.Google Scholar
- Bergström, H. and Högström, U.: 1978, ‘Calibration of a Three Axial Fiber Film System for Meteorological Turbulence Measurements’, Dantec Information, submitted.Google Scholar
- Businger, J. A., Wyngaard, J. C., Izumi, Y., and Bradley, E. F.: 1971, ‘Flux-Profile Relationships in the Atmospheric Surface Layer’, J. Atm. Sci. 28, 181–189.Google Scholar
- Dyer, A. J.: 1974, ‘A Review of Flux-Profile Relationships’, Boundary-Layer Meteorol. 7, 363–372.Google Scholar
- Dyer, A. J. and Bradley, E. F.: 1982, ‘An Alternative Analysis of Flux-Gradient Relationships at the 1976 ITCE’, Boundary-Layer Meteorol. 22, 3–19.Google Scholar
- Dyer, A. J. and Hicks, B. B.: 1970, ‘Flux-Gradient Relationships in the Constant Flux Layer’, Quart. J. Roy. Meteorol. Soc. 96, 715–721.Google Scholar
- Dyer, A. J., Garratt, J. R., Francey, R. J., Mc Ilroy, I. C., Bacon, N. E., Hyson, P., Bradley, E. F., Denmead, O. T., Tsvang, L. R., Volkov, Y. A., Koprov, B. M., Elagina, L. G., Sahashi, K., Monji, N., Hanafusa, T., Tsukamoto, O., Frenzen, P., Hicks, B. B., Wesley, M., Miyake, M., and Shaw, W.: 1982, ‘An International Turbulence Comparison Experiment (ITCE 1976)’, Boundary-Layer Meteorol. 24, 181–209.Google Scholar
- Foken, Th. and Skeib, G.: 1983, ‘Profile Measurements in the Atmospheric Near-Surface Layer and the Use of Suitable Universal Functions for the Determination of the Turbulent Energy Exchange’, Boundary-Layer Meteorol. 25, 55–62.Google Scholar
- Gibson, M. M. and Launder, B. E.: 1978, ‘Ground Effects on Pressure Fluctuations in the Atmospheric Boundary Layer’, J. Fluid Mech. 86, 491–511.Google Scholar
- Högström, U.: 1982, ‘A Critical Evaluation of the Aerodynamical Error of a Turbulence Instrument’, J. Appl. Meteorol. 21, 1838–1844.Google Scholar
- Högström, U.: 1985, ‘Von Kármán's Constant in Atmospheric Boundary Layer Flow: Re-evaluated’, J. Atm. Sci. 42, 263–270.Google Scholar
- Koprov, B. M. and Sokolov, D. Yu.: 1973, ‘Spatial Correlation Functions of Velocity and Temperature Components in the Surface Layer of the Atmosphere’, Izv. Atmospheric and Oceanic Physics 9, 178–182 (English translation pp. 95–98).Google Scholar
- Lumley, J. L. and Panofsky, H. A.: 1964, The Structure of Atmospheric Turbulence, Interscience, New York, 239 pp.Google Scholar
- Nicholls, S. and Smith, F. B.: 1982, ‘On the Definition of the Flux of Sensible Heat’, Boundary-Layer Meteorol. 24, 121–127.Google Scholar
- Purtell, L. P., Klebanoff, P. S., and Buckley, F. T.: 1981, ‘Turbulent Boundary Layer Flow at Low Reynolds Number’, Phys. Fluids 24, 802–811.Google Scholar
- Rasmussen, K. R., Larsen, S. E., and Jörgensen, F. E.: 1981, ‘Study of Flow Deformation Around Wind-Vane Mounted Three-Dimensional Hot-Wire Probes’, Disa Information, 26, 27–34.Google Scholar
- Slob, W. H.: 1978, ‘The Accuracy of Aspiration Thermometers’, KNMI Scientific Report W.R. 78-1, De Bilt, 26 pp.Google Scholar
- Smedman, A. S. and Lundin, K.: 1986, ‘Influence of Sensor Configuration on Measurements of Dry and Wet Bulb Temperature Fluctuations’, J. Atm. and Oceanic Tech., submitted.Google Scholar
- Tennekes, H.: 1973, ‘The Logarithmic Wind Profile’, J. Atm. Sci. 30, 234–238.Google Scholar
- Thom, A. S.: 1971, ‘Momentum Absorption by Vegetation’, Quart. J. Roy. Meteorol. Soc. 97, 414–428.Google Scholar
- Webb, E.: 1970, ‘Profile Relationships: The Lon-Linear Range and Extension to Strong Stability’, Quart. J. Roy. Meteorol. Soc. 96, 67–90.Google Scholar
- Wyngaard, J. C.: 1981, ‘The Effects of Probe-Induced Flow Distortion on Atmospheric Turbulence Measurements’, J. Appl. Meteorol. 20, 784–794.Google Scholar
- Wyngaard, J. C., Coté, O. R., and Izumi, Y.: 1971, ‘Local Free Convection, Similarity and the Budgets of Shear Stress and Heat Flux’, J. Atm. Sci. 28, 1171–1182.Google Scholar
- Yaglom, A. M.: 1977, ‘Comments on Wind and Temperature Flux-Profile Relationships’, Boundary-Layer Meteorol. 11, 89–102.Google Scholar
- Zilitinkevich, S. S. and Chalikov, D. V.: 1968, ‘Determining the Universal Wind-Velocity and Temperature Profiles in the Atmospheric Boundary Layer’, Izv. Atmospheric and Oceanic Physics 4, 294–302 (English version: pp. 165–170).Google Scholar