A study of oceanic internal waves using satellite imagery and ship data

• Published in: Remote sensing of environment 1976, Vol.5 (2), p.125-135
• Main Authors: Apel, John R., Michael Byrne, H., Proni, John R., Sellers, Ronald
• Format: Article
• Language: English
• ISSN: 0034-4257; 1879-0704
• DOI: 10.1016/0034-4257(76)90043-2

Surface manifestations of oceanic internal waves have been studied in Landsat-1 and -2 data since 1972. The internal waves appear as periodic, intermittent variations in the surface optical reflectivity and are visible from spacecraft, aircraft, and surface vehicles under certain circumstances. The Landsat data suggest that the source of the waves is semidiurnal and diurnal tidal action at the edge of the continental shelf. A study of the wave characteristics yields considerable insight into the physics of their excitation, propagation, and dissipation. Packets have been observed from the Gulf of Maine to Cape Hatteras and in images taken off the U.S. and African east and west coasts, the Gulf of Mexico and the Caribbean, The Gulf of California, the Sulu Sea, and the Baltic. The internal wave groups show an orderly variation in wavelength from front to rear of the packet, due to a combination of frequency dispersion and nonlinear amplitude effects. An oceanographic cruise was carried out in synchronism with two 18-day Landsat-1 cycles, and data were taken on temperature, density variations, acoustic echoes, and surface slicks accompanying the internal waves. The data were satisfactorily correlated with spacecraft and U-2 imagery taken simultaneously.