Ice-breaker navigation in Mathiessen Strait

Landfast ice, which is common around islands and along the margins of the Kara Sea, has variable thickness and can be heavily ridged. Icebreaker navigation in landfast ice such as in the Mathiessen Strait, between Nordenskjold Archipelago and the mainland, can therefore be difficult. The varied nature of the ice in this strait can be seen in the ERS-1 SAR image of 28 November 1993 (see the location of the SAR image ). This image was particularly useful because it was received and used by "Sovetsky Soyuz" during its westward cruise from the East Siberian Sea to the Kara Gate. Ice observations made onboard the "Sovetsky Soyuz" showed that the ice in Mathiessen Strait (site A) consisted of
1) nilas about 5 cm thick (landfast ice) with dark SAR signature,
2) 1 - 2 km large mostly smooth, snow-free floes 30-40 cm thick observed near the landfast ice boundary, and
3) highly compressed and ridged first-year ice.
The SAR signature of the ridged region is a mixture of brighter and darker patches.
The image also shows the track of the "Sovetsky Soyuz" in the ice (indicated by dark arrows). Other characteristic features are regions of 90 - 100% concentration of pancake ice causing high backscatter and bright signature in the SAR image (site B), and new landfast ice in bays, inlets and estuaries formed during calm weather. This ice is identified as dark homogeneous areas in the SAR image (site C).

This image is a classified ice map based on the SAR image in this example.

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