Multidecadal variability in the Arctic/North Atlantic climate system

Ice Thickness

This movie shows the simulated ice thickness. Prevailing winds produce very thick ice off Greenland (red color) with a gradual decrease the towards siberian coast (blue color). Often on-shore winds ridge the ice increasing its thickness. During summer vast areas of the arctic seas are ice-free; in winter they are ice-covered. The prevailing clockwise ice drift is associated with the anticyclonic arctic winds. This drift transports ice further to the south through Fram Strait and supplies the North Atlantic with fresh water.

Sometimes almost half of the Arctic is covered by thin ice (blue), sometimes it becomes thicker (yellow and red). These periods coincide with the positive and negative phases of the atmospheric pressure variations driven by decadal and multidecadal modes of arctic variability.

There is a substantial drop of ice thickness during the last decade. Although this ice mass decrease is regional, it mainly occurs in the siberian portion of the Arctic; near the Greenland and Canada coast the ice became even thicker.

Ice Concentration

Ice concentration is a relative area of ocean covered by ice (the higher the concentration the more ocean is ice-covered). Simulated ice concentration is shown in this movie.

There is a strong seasonal cycle with substantial decrease of ice area in summer. Arctic seas in summer are often ice-free. In winter, the Arctic Ocean is almost completely covered by ice (brown color). However, this ice cover is not uniform. The major portion of ice is presented by multiyear ice which is thicker than 2 m. Some portion is presented by young, much thinner ice.

Summer reduction of ice concentration in some years is associated with the decadal and multidecadal modes of arctic variability. When these modes are in their positive phases (like in the 1990s) there is a substantial decrease of ice area in the central Arctic.

• Back (Salinity and Temperature)
• Introduction
• Next (Sea Level)