Ocean internal wave spectra inferred from seismic reflection transects

Abstract

Internal waves affect many important dynamical processes in the ocean, but in situ observations of internal waves are infrequent and spatially sparse. Here we show that remote sensing of internal waves by marine seismic reflection methods can provide quantitative information on internal wave energy and its spatial variability at high lateral resolution and full ocean depth over large volumes of the ocean. Seismic images of the Norwegian Sea water column show reflections that capture snapshots of finestructure displacements due to internal waves. Horizontal wave number spectra derived from digitized reflection horizons in the open ocean compare favorably to the Garrett-Munk tow spectrum of oceanic internal wave displacements. Spectra within 10 km laterally and 200 m vertically of the continental slope show enhanced energy likely associated with internal wave-sloping boundary interactions.