Deep Ocean Wave Measurements Using a Vertically Oriented Sonar

Abstract

A vertically oriented 200-kHz sonar is used to make estimates of (one-dimensional) surface wave spectra in the deep ocean. Two independent approaches are used to determine wave spectra from this system: a direct measurement of range to the surface and the vertical velocity estimate of the surface. Estimated wave spectra are compared with observations from a Datawell Waverider buoy positioned directly above the acoustic instrument. Comparisons are provided for relatively calm conditions and also during a period of mixed swell and wind waves forced by a 13 m s?1 wind. Wave spectra from the three estimates appear qualitatively similar and agree to within 10% in total wave energy density.