Real-time use of ERS-1 SAR imagery for monitoring the ice in the Baltic Sea

Two demonstration experiments have been carried out in the Baltic Sea, using ERS-1 SAR imagery for ice monitoring. The benefits of these data for winter navigation purposes were evaluated, using questionnaires and personal communication as the basic information sources for interpretations. The satellite imagery proved to be useful for ship routing of merchant vessels and for icebreaker assistance. A resolution of 200 m gave adequate information onboard the icebreakers, although 100 m was preferred to preserve the small-scale structures. A very stable ice situation and the lack of full image coverage over the whole area limited the practical use for ice mapping.