Swedish Ice Service

The ice extent at sea is of great importance to shipping and ice breaker assistance is often required, particularly when vessels are destinated to ports in northern Sweden.
During winter time, the ice conditions are monitored on a daily basis, usually during the period late November – late May.
(Click to enlarge picture)

The ice meteorologist receives detailed reports on ice type and ice thickness, partly from observers along the coast (i.e. pilots), partly from the icebreakers in service which are sailing around the clock in ice-infested waters. Aireal reconnaissance from icebreaker-based helicopters is also carried out.

Satellite images, mainly from the US weather satellites (NOAA-15, NOAA-16 and NOAA-17) are used when available to present the large-scale ice conditions (pixel size 1000x1000 meters), provided clear skies.

More detailed ice information (up to 20x20 meters) can be obtained from a specific satellite based instrument called Synthetic Aperture Radar (SAR). SAR-sensors are available for instance on the commercial Canadian RADARSAT (operational since 1996) and on the European ENVISAT. Data from ENVISAT can be expected during spring/summer 2003.

A correct description of the ice coverage is also needed input to the weather forecast models as the ice extent at sea plays a significant role in modifying the weater in coastal areas, both concerning temperature and clouds/precipitation.
Finally, the result of the daily ice mapping procedure forms a part of a data base, from which climate statistics or other useful information on the sea ice surrounding Sweden can be extracted.