When polar seas freeze and ice forms, it is not only due to cold air chilling the surface of the water.
When polar seas freeze and ice forms, it is not only due to cold air chilling the surface of the water. Even more important is that warm water is prevented from rising to the surface from the depths of the ocean, due to the much lower salinity of the surface water. Researchers from the University of Gothenburg and elsewhere have described this effect in a new scientific study.
Sea ice forms in the polar regions because it gets so cold in winter. However, cold water is heavier than warm water, so the chilled water should sink and not remain on the surface. This sinking should bring the warmer water back to the surface preventing ice to form in the oceans. Researchers from the University of Gothenburg and elsewhere are now presenting an explanation as to why it is not so. The study is presented in the journal Science Advances.
“The salinity of the surface water is lower, thanks to the supply of freshwater from melting ice at the poles and precipitation to the ocean. The difference in salinity between the surface water and the deeper water is an important factor for the formation of sea ice at low temperatures at the poles. Without the difference in salinity, the water would not have become stratified, leading to continuous mixing of sea water, thus preventing the formation of ice,” says Fabien Roquet, professor of physical oceanography at the University of Gothenburg.
Read more at University of Gothenburg
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