Abstract
Ramp patterns in scalar traces such as temperature are the signature of coherent structures. A pseudo-wavelet analysis technique was developed in which ideal saw-tooth patterns of varying size were used as basis functions and fitted to temperature and velocity data. Data recorded from three very different vegetation stands were examined in this study. It was found that the most probable structure duration for the forest canopy was in the range 35–40 s, for the orchard canopy it was 20–25 s and for the maize it was 15–20 s. When expressed in non-dimensional form, the structure duration probability distribution for the maize canopy was about a decade larger than for the forest canopy, with the orchard canopy intermediate. The mean eddy duration versus wind shear relation falls on a narrow band for all three canopies, indicating that wind shear at the canopy top is the determining factor for the scale of the coherent eddies. The inverse of duration and intermittency of coherent structures exhibits a tendency of independence from wind shear at higher wind shear values. Coherent structures transport heat in a more efficient way than do smaller scale, less coherent motions. In all the canopies, the heat flux fractions associated with coherent structures are at least 10% higher than the corresponding time fraction.
Similar content being viewed by others
References
Antonia, R. A., Rajagopalan, S., and Chambers, A. J.: 1983, ‘Conditional Sampling of Turbulence in the Atmospheric Surface Layer’,J. Clim. Appl. Meteorol. 22, 69–78.
Bacry, E., Arneodo, A., Frisch, U., Gagne, Y., and Hopfinger, E.: 1991, ‘Wavelet Analysis of Fully Developed Turbulence Data and Measurements of Scaling Exponents’,Turbulence and Coherent Structures, Kluwer Academic Publishers, pp. 203–216.
Blackwelder, R. F. and Kaplan, R. E.: 1976, ‘On the Bursting Phenomenon near the Wall in Bounded Turbulent Shear Flows’,J. Fluid Mech. 76, 89–112.
Collineau, S. and Brunet, Y.: 1993a, ‘Detection of Turbulent Coherent Motions in a Forest Canopy, Part I: Wavelet Analysis’,Boundary-Layer Meteorol. 65, 357–379.
Collineau, S. and Brunet, Y.: 1993b, ‘Detection of Turbulent Coherent Motions in a Forest Canopy, Part II: Time-Scales and Conditional Averages’,Boundary-Layer Meteorol. 66, 49–73.
Daubechies, I.: 1992,Ten Lectures on Wavelets, CBMS-NSF Regional Conference Series in Applied Mathematics, S.I.A.M.,61, 357 pp.
Farge, M.: 1992, ‘Wavelet Transforms and Their Applications to Turbulence’,Ann. Rev. Fluid Mech. 24, 395–457.
Gamage, N. and Blumen, W.: 1993, ‘Comparative Analysis of Low-Level Cold Fronts: Wavelet, Fourior, and Empirical Orthogonal Function Decompositions’,Mon. Wea. Rev. 121, 2867–2878.
Gamage, N. and Hagelberg, C.: 1993, ‘Detection and Analysis of Microfronts and Associated Coherent Events Using Localized Transforms’,J. Atmos. Sci. 50, 750–756.
Gao, W., Shaw, R. H., and Paw U, K. T.: 1989, ‘Observation of Organized Structure in Turbulent Flow within and above a Forest Canopy’,Boundary-Layer Meteorol. 47, 349–377.
Gao, W., Shaw, R. H., and Paw U, K. T.: 1992, ‘Conditional Analysis of Temperature and Humidity Microfronts and Ejection/Sweep Motions within and above a Deciduous Forest’,Boundary-Layer Meteorol. 59, 35–57.
Gao, W. and Li, B. L.: 1993, ‘Wavelet Analysis of Coherent Structures at the Atmospheric-Forest Interface’,J. Appl. Meteorol. 32, 1717–1725.
Haar, A.: 1909, ‘Zur Theorie der Orthogonalen Funktionensysteme Gottingen’, Juli 1909.
Katul, Gabriel G., Parlange, Mark B., and Chu, Chia R.: 1993, ‘Intermittency of Land Surface Hear Fluxes: The Orthonormal Wavelet Approach’, Submitted toWater Resourc. Res.
Liandrat, J. and More-Bailly, F.: 1990, ‘The Wavelet Transform: Some Applications to Fluid Dynamics and Turbulence’,European J. Mechanics, B/Fluids,9(1), 1–19.
Mahrt, L. and Gibson, W.: 1992, ‘Flux Decomposition into Coherent Structures’,Boundary-Layer Meteorol. 60, 143–168.
Meneveau, C.: 1991, ‘Analysis of Turbulence in the Orthonormal Wavelet Representation’,J. Fluid Mech. 232, 469–520.
Neumann, H. H., den Hartog, G., and Shaw, R. H.: 1988, ‘Leaf Area Measurement during Leaf-Fall for Deciduous Forest Based on Hemispheric Photographs and Leaf-litter Collection’,Agric. For Meteorol. 45, 325–345.
Paw U, K. T., Brunet, Y., Collineau, S., Shaw, R. H., Maitani, T., Qiu, J., and Hipps, L.: 1992, ‘On Turbulent Coherent Structures in and above Agricultural Plant Canopies’,Agric. For. Meteorol. 61, 55–68.
Qiu, J., Shaw, R. H., and Paw U, K. T.: 1991, ‘Comparison of Turbulence Statistics and Structures at Four Vegetation Canopies’, Preprints,20th AMS Conference on Agricultural and Forest Meteorology, Salt Lake City, Utah, September 10–13.
Raupach, M. R., Finnigan, J. J. and Brunet, Y.: 1989, ‘Coherent Eddies in Vegetation Canopies’,Proceedings Fourth Australasian Conference on Heat and Mass Transfer, Christchurch, New Zealand, 9–12, May, pp. 75–90.
Raupach, M. R., Antonia, R. A., and Rajagopalan, S.: 1991, ‘Rough-Wall Turbulent Boundary Layer’,Appl. Mech. Rev. 44(1), 1–25.
Schols, J. L. J.: 1984, ‘The Detection and Measurement of Turbulent Structures in the Atmospheric Surface Layer’,Boundary-Layer Meteorol. 29, 39–58.
Shaw, R. H., den Hartog, G., and Neumann, H. H.: 1988, ‘Influence of Foliar Density and Thermal Stability on Profiles of Reynolds Stress and Turbulence Intensity in a Deciduous Forest’,Boundary-Layer Meteorol. 45, 391–409.
Shaw, R. H., Paw U, K. T., and Gao, W.: 1989, ‘Detection of Temperature Ramps and Flow Structures at a Deciduous Forest Site’,Agric. For. Meteorol. 47, 123–138.
Yamada, M. and Ohkitani, K.: 1991, ‘Orthonormal Wavelet Analysis of Turbulence’,Fluid Dynamics Research 8, 101–115.
Zhang, C., Shaw, R. H., and Paw U, K. T.: 1991, ‘Spatial Characteristics of Turbulent Coherent Structures within and above an Orchard Canopy’,Proceedings of the Fifth International Conference on Precipitation Scavenging and Atmospheric Surface Exchange Processes, Richland, Washington, 15–19 July.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Qiu, J., Paw U, K.T. & Shaw, R.H. Pseudo-wavelet analysis of turbulence patterns in three vegetation layers. Boundary-Layer Meteorol 72, 177–204 (1995). https://doi.org/10.1007/BF00712394
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00712394