Icing of the Chukchi Sea in winter

Abstract

The modern change trends for the navigation conditions in the Northern Sea Route, belonging to the Chukchi Sea in winter were investigated. In the context of ongoing climatic changes and reducing Arctic ice cover, shipowners are using this transport route. Trial voyages of merchant ships in the eastern part of the Northern Sea Route are being carried out in the winter-spring period; however, shipping has not yet become massive due to difficult ice conditions and insufficient knowledge of the navigation areas. This study was carried out on the basis of information on ice thickness obtained from the GLORYS12.v1 reanalysis databases, NASA ICESat, ICESat-2 and Ice Bridge missions and the Global Sea Ice Digital Data Bank for 1993–2018 for the period from November to March. The probabilities of solid ice posing a danger to navigation were assessed (using the example of “YamalMax” vessels). The distributions of these probabilities over the water area of the Chukchi Sea were presented in a map form. It was found that the navigation conditions improved in most areas of the Chukchi Sea; however, in the southern part of the sea they worsened. This effect was most pronounced in November; in the subsequent winter months, its intensity decreased. The revealed effect is presumably a consequence of the warming of the Arctic climate, leading to the melting of ice massifs of Greenland, the Canadian archipelago and Alaska. The latter causes an imbalance in the levels of the Chukchi and Bering Seas and a change in the directions of surface currents, capable of both delivering ice to the strait and carrying it to the north. The revealed trends suggest further complication of ice conditions in the southern part of the Chukchi Sea, as a result of which even vessels with a high ice class may require icebreaker assistance in November and December.