Abstract
Hot-wire anemometers were used to measure air temperature and the three velocity components of the wind within and above a maize canopy. From digitized anemometer outputs, correlation coefficients for vertical heat flux and turbulent momentum transfer were calculated. A comparison of these coefficients with profiles of mean wind speed and mean temperature indicates that the main features of the turbulence may be explained in terms of the usual mixing-length theory. Instantaneous records of heat and momentum flux, however, indicate the existence of other competing turbulent mechanisms due to the unsteady, non-equilibrium nature of the turbulent flow. Regimes of flow dominated by mechanical and/or thermal mixing are indicated. Spectral results show that high shear and turbulent intensity levels as well as the presence of the maize leaves and stalks as vortex-shedding surfaces complicate the energy transfer mechanism. An energy balance between radiation and convection reveals that the energy budget is primarily a balance between solar radiation and the flux of latent heat.
Similar content being viewed by others
References
Allen, L. H., Jr.: 1968, Turbulence and Wind Speed Spectra Within a Japanese Larch Plantation, J. Appl. Meteorol. 7, 73–78.
Allen, L. H., Jr., Desjardins, R. L., and Lemon, E. R.: 1974, Line Source Carbon Dioxide Release. I. Field Experiment, Agron. J., 65, 609–615.
Baines, G. B. K.: 1972, Turbulence in a Wheat Crop, Agric. Meteorol. 10, 93–105.
Batchelor, G. K.: 1967, Homogeneous Turbulence, Cambridge, The University Press.
Brown, K. W. and Covey, W.: 1966, The Energy Budget of the Micrometeorological Transfer Process Within a Cornfield, Agric. Meteorol. 3, 73–96.
Cooley, J. W. and Tukey, O. W.: 1965, An Algorithm for the Machine Calculation of Complex Fourier Series, Mathematics of Computation, 19, 297–301.
Isobe, S.: 1972, A Spectral Analysis of Turbulence in a Corn Canopy, Bull. Nat. Inst. Agric. Sci. (Japan), A19, 101–113.
Kaimal, J. C. and Businger, J. A.: 1970, Case Studies of a Convective Plume and a Dust Devil, J. Appl. Meteorol. 9, 612–620.
Lemon, E., Stewart, D. W., and Shawcroft, R. W.: 1971, The Sun's Work in a Cornfield, Science 1974, 371–378.
Lin, C. C.: 1953, On Taylor's Hypothesis and the Acceleration Terms in the Navier-Stokes Equations, Quart. Appl. Math. 10, 295–306.
Lumley, J. L.: 1965, Interpretation of Time Spectra Measured in High-Intensity Shear Flows, Physics Fluids 8, 1056–1062.
Lumley, J. L. and Panofsky, H. A.: 1964, The Structure of Atmospheric Turbulence, InterScience Publishers.
McBean, G. A.: 1968, An Investigation of Turbulence Within the Forest, J. Appl. Meteorol. 7, 410–416.
McBean, G. A.: 1970, “The Turbulent Transfer Mechanisms in the Atmospheric Surface Layer”, Ph.D. Thesis, University of British Columbia, 120 pp.
McBean, G. A. and Miyake, M.: 1972, Turbulent Transfer Mechanisms in the Atmospheric Surface Layer, Quart. J. Roy. Meteorol. Soc., 98, 383–398.
Priestley, C. H. B.: 1959, Turbulent Transfer in the Lower Atmosphere, University of Chicago Press.
Rabiner, L. R. and Rader, C. M.: 1972, Digital Signal Processing, IEEE Press.
Shaw, R. H., Silversides, R. H., and Thurtell, G. W.: 1974, Some Observations of Turbulence and Turbulent Transport Within and Above Plant Canopies, Boundary-Layer Meterol. 5, 429–449.
Sinclair, T. R.: 1971, “An Evaluation of Heat Angle Effect on Maize Photosynthesis and Productivity”, Ph.D. Thesis, Cornell University.
Taylor, G. I.: 1938, “Some Recent Developments in the Study of Turbulence”, Proc. 5th Int. Congr. Appl. Mech., Cambridge (U.S.A.), 294–310.
Uberoi, M. S. and Corrsin, S.: 1953, Diffusion of Heat from a Line Source in Isotropic Turbulence, N.A.C.A. Rept., NQ1 142.
Uchijima, Z. and Wright, J. L.: 1964, An Experimental Study of Air Flow in a Corn Plant—Air Layer, Bull. Nat. Inst. Agric. Sci. (Japan), A, 19, 19–65.
Waggoner, P. E. and Reifsnyder, W. E.: 1968, Simulation of Temperature, Humidity and Evaporation Profiles in a Leaf Canopy, J. Appl. Meteorol. 7, 400–409.
Additional information
Contribution of the Sibley School of Mechanical and Aerospace Engineering, Cornell University, in cooperation with the Agricultural Research Service, U.S. Department of Agriculture, Ithaca, N.Y., U.S.A. and the Cornell University Agricultural Experiment Station. Department of Agronomy Series No. 1116.
Sibley School of Mechanical and Aerospace Engineering, Cornell University; U.S. Department of Agriculture, Gainesville, Florida Section for Estuary and Fjord Studies, River and Harbour Laboratory, Technical University of Norway, Trondheim, Norway; State Univ. of New York at Buffalo; and U.S. Department of Agriculture and Cornell University; respectively.
Rights and permissions
About this article
Cite this article
Bill, R.G., Allen, L.H., Audunson, T. et al. Turbulent transport within and above a maize canopy. Boundary-Layer Meteorol 10, 199–220 (1976). https://doi.org/10.1007/BF00229285
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00229285