Decomposition of wind velocity and temperature fluctuations into wave and turbulent signals, using wavelet transform

Authors

  • Nisia Krusche Departamento de Geociências, FURG, Rio Grande, RS.
  • Osvaldo Luis Leal de Moraes Departamento de Física, Centro de Ciências Naturais e Exatas - CCNE Universidade Federal de Santa Maria - UFSM, Santa Maria, RS.
  • Birajara S. Machado Departamento de Física, FURG, Rio Grande, RS.

DOI:

https://doi.org/10.5902/2179460X36910

Abstract

In the stable stratified atmospheric boundary layer, spectra might be affected by several kinds of waves. Since the problem of turbulent diffusion is closely related to the spectra of wind velocity fluctuations, it is necessary to separate the contributions of those waves from that of turbulence. Discrete wavelet packets transform was applied to temperature and vertical velocity fluctuations measured in Candiota, RS (31°28´ S, 53°40´ W), sampled with a frequency of 10 Hz and 1 Hz. In these datasets, waves have been detected through cospectral techniques. Wavelet transform was used to decompose the series. It allowed identification of those contributions that are related to the detected waves, which were then removed from the original signals. Therefore, this method may be used to decompose the series in two signals, one containing waves and other corresponding to random turbulence of the flow.

Downloads

Download data is not yet available.

References

Farge, M. ,1992, Wavelet Transforms and Their Applications to Turbulence, Annual Review of Fluid Mechanics, 24, 395-457.

Nieuwstadt, F. T. M., Tennekes H., 1981, A Rate Equation for the Nocturnal Boundary-layer Height, J. Atmos. Sci., 38, 1418-1428.

Qiu, J., Paw U, K. T., Shaw, R. H., 1995, The Leakage Problem of Orthonormal Wavelet Transform when applied to Atmospheric Turbulence, J. Geophys. Res., 100 (D12), 25769-25779.

Rees, J. M., 1991, On the Characteristics of Eddies in the Stable Atmospheric Boundary Layer, Boundary-Layer Meteorol., 55, 325-343.

Rees, J. M. , Anderson P. S. , King J. C., 1998, Observations of Solitary Waves in the Stable Atmospheric Boundary Layer, Boundary-Layer Meteorol., 86, 47-61.

Stull, R.B., 1988, An Introduction to Boundary Layer Meteorology, Kluwer Academic Publishers, Dordrecht, Holanda.

Turner, B. J. , Leclerc M. Y., 1994, Conditional Sampling of Coherent Structures in Atmospheric Turbulence using the Wavelet Transform, J. Atmos. Ocean. Tech., 11, 205-209.

Wetzel, P.J., 1982, Toward Parameterization of the Stable Boundary Layer, J. Appl. Meteor., 21 (1), 7-13.

Wyngaard, J. C., 1975, modeling the Planetary Boundary Layer- extension to the Stable Case, Boundary-Layer Meteorol., 9, 441-460.

Yamada, T., 1979, Prediction of the Nocturnal Surface Inversion Height, J. Appl. Meteor., 18, 526-531.

Downloads

Published

2000-01-14

How to Cite

Krusche, N., Moraes, O. L. L. de, & Machado, B. S. (2000). Decomposition of wind velocity and temperature fluctuations into wave and turbulent signals, using wavelet transform. Ciência E Natura, 141–152. https://doi.org/10.5902/2179460X36910