Physical and stable isotopic properties and growth processes of sea ice collected in the southern Sea of Okhotsk

This study presents physical and stable isotopic properties of sea ice in t he southernmost section of the Sea of Okhotsk on the basis of observations and measurements made in 1995 and 1996 midwinter cruises. Structural analys is revealed that ice was predominantly of the granular type. Saucer-shaped cores and wedges were seen in the cross sections of the pancakes, which ind icate a rafting event in the early stage of the pancake formation. The frac tion of snow with respect to the total ice mass was estimated at similar to 8% from independent delta(18)O and density measurements. From these findin gs we conclude that the initial growth mechanisms of the sea ice over this region are by the frazil pancake cycle with rafting and by the snow ice for mation. Analysis also shows that the formation of the snow ice induces simi lar to 10% more salt flux through the additional freezing of the seawater. In a short (synoptic) timescale this implies that snow becomes a negative ( salting) rather than a positive (freshening) source for the buoyancy flux. These results suggest critical influence of the rapid formation of the fraz il pancakes and snow ice under stormy conditions on the salt and buoyancy f luxes over the region.