Internal waves in Denmark

The ERS-1 SAR image from 13 October 1993 shows the northern part of the Kattegatt between the Skagen peninsula in Denmark and the western coast of Sweden. Packets of internal waves are visible in the dark region which is in the lee of the wind front, represented by the north-south boundary between rough (light) and calm (dark) water.

The wavelengths indicate that the group is propagating west, as the spacing between waves then increases away from the leading edge as would be expected in dispersive waves. The crest lengths are seen to decrease towards the trailing edge.

It is assumed that the tidal currents are responsible for creating the internal waves. The bright linear feature to the east of the image, oriented in a north-south direction is thought to show current shear. The local wind speed was recorded as 7 m/s from the southwest.
See the interpreted image to better identify the features.

NERSC, Bergen, Norway

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry