Marine icing observed on KV Nordkapp during a cold air outbreak with a developing polar low in the Barents sea.

Abstract

Marine icing is a phenomenon that may occur for temperatures below subfreezing where sea spray either is lofted from the sea surface or being generated by waves interacting with a ship or a structure. On a voyage from Tromsø to the waters east of Bjørnøya late February 1987, the Norwegian Coast Guard vessel KV Nordkapp experienced heavy icing due to a polar low that raged over these waters during the voyage. This polar low developed in an unstable air mass due to a cold-air outbreak over relatively warm waters. KV Nordkapp experienced air temperatures in the range of -10°C to -20°C, and was moving against 20-30 m/s winds producing waves up to 7.5 m high. During the icing event KV Nordkapp accumulated 110 tons of ice. The icing was encountered all the way from the hull just above the water level to the top of the wheelhouse. The icing event is analysed and calculations made for comparison between observations and modelling results.