Surface Currents Fields from SAR imagery
Oceanic features like fronts, eddies, and internal waves become visible in SAR images via hydrodynamic modulation of the surface roughness, which determines the backscattered power. Areas of increased surface roughness, such as the front between the Rhine plume and surrounding waters at the Dutch coast, appear bright. MARSAIS contains a tool for retrieving quantitative information on current gradients from such SAR signatures. This tool facilitates the oceanographic interpretation of SAR images.
Example 1: Retrieving Information on Surface Currents from SAR Signatures
This ERS-1 SAR image covers 48 km x 48 km of the mouth of the Rhine river at the Dutch coast. The image has clear signatures of a freshwater plume released by the Rhine river, which is floating on the seawater of the North Sea. The SAR image was acquired on 13 October 1993, 21:46 UTC (orbit 11740, frame 1035).
More examples:
Algorithm:
The M4S model estimates surface currents from ERS SAR imagery.