Experimental Studies of Oceanic Heat Flux in a Frozen Sea

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The vertical oceanic heat flux is investigated experimentally as a relation with the surfce conditions of a flozen sea.Laboratory experiments were carried out to examine the processes of frazil ice formation under a cold wind conditions as a function of air temperature(-10 -30゜c) and wind speed (2-6m/s). A plexiglass test tank of 0.4m x 2.0m x 0.6m was filled with 32 per mill salt water. Frazil ice crystals produced in open water were transported downward by the wind-driven current,and the wind-generated open water was maintained within two hours or more. At a higher wind speed, a significant amoumt of supercoolsd water formed within the interior of the tank,and did not disappear despite rapid frazi ice production.Field experiments were also carried out to observe the magnitude of heat flux flowed through a thin sea ice cover at lagoon Lake Saroma, Okhotsk Sea coast of Hokkaido, in February of 1986,1987,and 1988. Test pools(2x2m) were made by removing ice blocks from the fast ice sheet with a thickness of about 30 cm. Using sea ice sheet as a heat flow meter the oceanic heat flux was calculated as the difference between vertical heat flux within the sea ice sheet and the latent heat released by freezing at the ice-water interface. It was found that the oceanik heat flux cannot be neglected in the heat budfet of young sea ice because it was as large as compared with the latent heat of newly formed sea ice. when the sea ice was covered with snow the oceanic heat flux decreased,however after removing of the sno the heat flux increased. The effect of snow cover is also investigated as a snow-ice model.