Accession Number : AD0729014

Title :   Field Observations of Frequency Domain Statistics and Nonlinear Effects in Wind-Generated Ocean Waves,

Corporate Author : BRITISH COLUMBIA UNIV VANCOUVER INST OF OCEANOGRAPHY

Personal Author(s) : Garrett,John

Report Date : APR 1970

Pagination or Media Count : 189

Abstract : The objectives of this study were to show how far the statistical assumptions usually made in theories on continuum nonlinear interactions were relevant to the case of fetch-limited, wind-generated wave fields, and to observe some consequence of the nonlinearity as a check. Four wave fields were observed and described in terms of their power spectra and frequency-wavenumber spectra. Although their directional spectra were found to be strongly influenced by the particular arrangement of fetch at the observing site, their equilibrium power spectra agreed well with both theory and other observations, at least after correction for the observed currents. This agreement is important from the point of view of establishing the relevance of the results of this work to other field situations. Observations of the frequency domain statistics for these four wave fields indicated that the assumptions of stationarity and of normal distributions for the Fourier coefficients were correct to good accuracy. Two methods were tried for observing direct evidence of nonlinear effects in the wave field. One of these, the attempt to detect products of second order interactions in the frequency-wavenumber spectra, failed because of the poor resolution of the array of sensors. The other, the bispectrum, succeeded, with reasonable agreement being achieved between the observed bispectra and bispectra predicted from the power spectra using the results of perturbation theory. (Author)

Descriptors :   (*OCEAN WAVES, POWER SPECTRA), FOURIER ANALYSIS, PERTURBATION THEORY, INTERACTIONS, TIME SERIES ANALYSIS, CANADA, THESES

Subject Categories : Physical and Dynamic Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE