Nonlocal effect of internal waves on the ocean surface

The effects of nonlocal connection between an internal wave field and centimeter- and decimeter-scale waves were studied using the JUSREX-92 data. Centimeter-scale wave parameters were measured by means of a ship-mounted, X-band side-looking radar, decimeter-scale wave parameters were measured with a two-dimensional optical device (the wave spectrum analyzer) and parameters of the internal waves were measured by a towed, profiling batfish operated by the Atlantic Division of the Shirshov Institute of Oceanology. The authors show that disturbed regions of centimeter- and decimeter-scale surface waves exist at distances up to 1 km away from the region of internal waves. The spatial period of the surface wave spectral density variations can differ from the internal wave length, but the magnitude of this difference depends on the relative direction of surface wave propagation. These variations in the spectral density of decimeter-scale surface waves can be explained in terms of a standard kinematic model of the action of internal waves on wind waves. The variations in the spectral density of centimeter waves is a result of a cascade mechanism: the surface flow caused by the internal waves transforms the decimeter-scale waves, which then cause the centimeter-scale wave variations.