Istankeksperimenter

Eksperimenter innendørs studerer framtidig sjøis i Arktis. Dataene vil forberde vår forståelse av fryseprosesser i åpent hav, og hvordan dette påvirkes av bølger og turbulens inne i drivisen.

Ice tank experiments

Sea-ice is very efficient at damping high frequency waves, such that even a thin layer of frazil ice will eliminate surface ripples. However, in an Arctic Ocean with a much reduced ice cover (probable future scenario, IPCC, 2007) the wind will become much larger, generating higher amplitude waves with longer periods. Under the motion of these high-amplitude, long-period waves, frazil does not consolidate into a continuous ice sheet but coalesces together to form small, rounded ice pieces known as pancake ice. Only when the wave-field reduces or has been attenuated to such a degree that the relative motion between pancakes is slight can they freeze together to form a continuous ice sheet; the frazil−pancake−ice sheet cycle. The aim of the project: ‘Understanding the impact of a REduced ice Cover in the ARctic Ocean’ (RECARO) is therefore to study what the impact of the transition from the frazil−ice sheet cycle to a frazil−pancake−ice sheet cycle will be.
The study was carried out at the Hamburg Ship Model Basin (www.hsva.de), which runs one of the world’s largest refrigerated Arctic Environmental Test Basin (AETB, length: 30m, width: 6m). Over 20 partners from 10 European countries, Japan and the USA were involved in this work. It consisted of a two experimental phases, a two-week experiment in November 2007 and a one-week experiment in March 2008.

Figure 1 shows a schema of the layout of the AETB and the instruments used for the experiments. A photo of the two wave tanks (Tanks 2 and 3 shown on the schematic layout) is also shown.

Figure 2 showing the sampled ice.

Also some information about the experiment at Norsk Polarinstitutt.

The University of Bergen and the Norwegian Polar Institute are involved in the project. For more information contact Sara de la Rosa s.delarosa@gfi.uib.no ,  Sebastian Gerland gerland@npolar.no.