The first ERS‐1 SAR image over the Netherlands ‐ An appraisal for off‐shore areas

Abstract

The first ERS‐1 SAR image was acquired over the Waddensea on the 27th July 1991, ten days after launch. On basis of information on tidal situation and meteo information, a first appraisal has been made on the influence of wind and current actions on the radar backscatter signal over the shallow water surfaces. High tide occurred at time of acquisition over the eastern part of the image resulting in a uniform grey tone of the water surface. The outgoing tide was present at the western part where ebb currents influenced the variability in radar response in the tidal channels. The long ship wakes present off‐shore in the shipping lanes, indicate that surface currents are of little influence on the radar patterns visible. Wind action is low. Bottom configuration and water pollutants present may have influenced the surface capillary waves resulting in a complicated pattern in the radar backscatter. From this first image it is clear that the complicated interaction of bottom configuration, currents, water pollutants and wind action on the radar response of the C band ERS‐1 radar is not yet fully understood.