SAR observations of internal wave wakes from sea mounts

Abstract

The synthetic aperture radar on the European Space Agency Remote Sensing Satellite ERS-1 detected undular and V-shaped features on the ocean surface above the continental slope and shelf off eastern Australia near 31ºS. These are suggested to be expressions of transverse and oblique internal waves caused by the influence of seamounts and canyons on an energetic East Australian Current (EAC). The phase speed of the 1-km-wavelength internal waves was calculated from an assumed ocean density structure to be a little over 1 m s^-1 -close to the expected speed of the EAC. This meant that transverse waves could become 'anchored' behind canyons and ridges aligned across the EAC flow. Single-peak seamounts appeared to produce oblique waves with half angles generally around 45º, but sometimes less. Some of the seamounts causing the internal waves may have been as deep as 600 m.