Abstract
Observations have been made of the structure of turbulence and turbulent exchange within plant canopy layers. A new three-dimensional anemometer was used to measure the eddy fluxes of heat and momentum, and the related cospectra, within and above a corn crop and above a red pine forest. Measured values of momentum and heat fluxes, at each height within the corn canopy, were relatively constant proportions of the flux above the canopy, for the period of a day's observation. Extensive regions obeying a −5/3 power relation were found. Isotropy was found above the forest at high frequencies while above and within the corn crop, the ratios of the lateral and vertical spectral densities to the longitudinal component were less than the expected value in the − 5/3 region. In all situations, the vertical velocity spectra were more peaked than a ‘universal’ curve, particularly a vertical velocity spectrum from above the forest. It is suggested that the additional variance results from the mixing caused by the individual roughness elements. As expected, the spectra could not be normalized using the height above the soil surface to calculate a non-dimensional frequency, but scaling heights were estimated by matching the frequencies of the peak of each curve with that of the ‘universal’ curve. Cospectra of uw and wT within the corn canopy were of similar shape and frequency regime, and were basically similar in shape to cospectra above the crop. All of the cospectra were more sharply peaked than ‘universal’ cospectral curves.
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References
Allen, L. H. Jr.: 1968, ‘Turbulence and Wind Speed Spectra within a Japanese Larch Plantation’, J. Appl. Meteorol. 7, 73–78.
Baines, G. B. K.: 1972, ‘Turbulence in a Wheat Crop’, Agr. Meteorol. 10, 93–105.
Blackman, R. B. and Tukey J. W.: 1958, The Measurement of Power Spectra from the Viewpoint of Communications Engineering, Dover Publ. N.Y.
Brown, K. W. and Covey, W.: 1966, ‘The Energy Budget Evaluation of the Micrometeorological Transfer Processes within a Cornfield’, Agr. Meteorol. 3, 73–96.
Busch, N. E. and Panofsky, H. A.: 1968, ‘Recent Spectra of Atmospheric Turbulence’, Quart. J. Roy. Meteorol. Soc. 94, 132–148.
Byrne, G. F. and Rose, C. W.: 1972, ‘On the Determination of Vertical Fluxes in Field Crop Studies’, Agr. Meteorol. 10, 13–17.
Haugen, D. A., Kaimal, J. C., and Bradley, E. F.: 1971, ‘An Experimental Study of Reynolds Stress and Heat Flux in the Atmospheric Surface Layer’, Quart, J. Roy. Meteorol. Soc. 97, 168–180.
Hinze, J. O.: 1959, Turbulence, McGraw Hill, N.Y., 586 pp.
Isobe, S.: 1972, ‘A Spectral Analysis of Turbulence in a Corn Canopy’, Bull. Nat. Inst. Agr. Sci. (Japan), Series A 19, 101–113.
Jenkins, G. M. and Watts, D. G.: 1968, Spectral Analysis and its Applications, Holden-Day, San Francisco, 525 pp.
Lumley, J. L. and Panofsky, H. A.: 1964, The Structure of Atmospheric Turbulence, Interscience Publ., N.Y., 239 pp.
McBean, G. A.: 1968, ‘An Investigation of Turbulence within the Forest’, J. Appl. Meteorol. 7, 410–416.
Meroney, R. N.: 1968, ‘Characteristics of Wind and Turbulence In and Above Model Forests’, J. Appl. Meteorol. 7, 780–788.
Miyake, M., Stewart, R. W., and Burling, R. W.: 1970, ‘Spectra and Cospectra of Turbulence over Water, Quart. J. Roy. Meteorol. Soc. 96, 138–143.
Munn, R. E.: 1966, Descriptive Micrometeorology, Academic Press, N.Y., 245 pp.
Panofsky, H. A. and Mares, E.: 1968, ‘Recent Measurements of Cospectra for Heat Flux and Stress’, Quart. J. Roy. Meteorol. Soc. 94, 581–585.
Shaw, R. H., Kidd, G., and Thurtell, G. W.: 1973, ‘A Miniature Three-dimensional Anemometer for use Within and Above Plant Canopies’, Boundary-Layer Meteorol. 3, 359–380.
Silversides, R. H.: 1972, The Structure of Thermal Turbulence Above and Within Canopies of Zea Mays (L.) and Pinus Resinosa (AIT.)', Ph.D. Dissertation, Univ. of Guelph, Canada.
Tanner, C. B. and Thurtell, G. W.: 1969, ‘Anemoclinometer Measurements of Reynolds Stress and Heat Transport in the Atmospheric Surface Layer’, U.S. Army Electronics Command, R and D Tech. Report, ECOM 66-G22-F, 199 pp.
Thurtell, G. W., Tanner, C. B., and Wesely, M. L.: 1970, ‘Three-dimensional Pressure-Sphere Anemometer System’, J. Appl. Meteorol. 9, 379–385.
Waggoner, P. E. and Reifsnyder, W. E.: 1968, ‘Simulation of Temperature, Humidity and Evapora- tion Profiles in a Leaf Canopy’, J. Appl. Meteorol. 7, 400–409.
Wesely, M. L., Thurtell, G. W., and Tanner, C. B.: 1970, ‘Eddy Correlation Measurements of Sensible Heat Flux Near the Earth's Surface’, J. Appl. Meteorol. 9, 45–50.
Wright, J. L. and Brown, K. W.: 1967, ‘Comparison of Momentum and Energy Balance Methods of Computing Vertical Transfer Within a Crop’, Agron. J. 49, 427–432.
Wright, J. L. and Lemon, E. R.: 1966, ‘Photosynthesis under Field Conditions, VIII. Analysis of Wind Speed Fluctuation Data to Evaluate Turbulent Exchange within a Corn Crop’, Argon. J. 58, 255–261.
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Shaw, R.H., Silversides, R.H. & Thurtell, G.W. Some observations of turbulence and turbulent transport within and above plant canopies. Boundary-Layer Meteorol 5, 429–449 (1974). https://doi.org/10.1007/BF00123490
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DOI: https://doi.org/10.1007/BF00123490