Normalized spectra of turbulent fluctuations over ocean waves

Abstract

Spectral and cospectral analyses are performed on turbulence data obtained over natural ocean waves during BOMEX. Results are obtained for normalized spectra and cospectra. Significant scatter is observed throughout the spectra and cospectra with a larger degree of scatter in the low frequency range. Kolmogorov's -5/3 power law is found to describe the longitudinal and vertical velocity spectra in the high frequency range. However, it is not applicable to the lateral velocity spectra while results for the temperature spectra are inconclusive. Monin-Obukhov similarity theory well describes the vertical velocity spectra yet its application to horizontal velocity spectra is doubtful. Similarity theory does not seem to adequately describe the uw cospectra. Results from comparing similairt theory to temperature spectra and wT cospectra indicate the presence of an influence not accounted for by similarity theory. When compared, uw and wT cospectra are found to be significantly different. All computed spectra and cospectra are found to have a relatively larger amount of energy in the low frequency range than their respective over land spectra and cospectra.