Outflow of dense water from the Storfjord in Svalbard: A numerical model study

Recent investigations on deep water renewal point to the important role of dense water formed on the continental shelves surrounding the Arctic Ocean. In this investigation a hydrostatic, reduced gravity, primitive equation model for the simulation of the spatial and temporal evolution of gravity plumes on a continental slope is applied and compared to the observed outflow of a plume of dense water, originally formed in Storfjorden (Svalbard), into the Greenland Sea toward Fram Strait, The vertically integrated, nonlinear, rotational model accounts for the entrainment of water mass properties from a spatially structured but stagnant ambient water body, This study reveals that part of the dense water, in accordance with earlier estimates, spreads northward along the eastern side of Fram Strait. Another branch of the plume, guided by the topography, flows into a deep trench east of the Knipovitch Ridge to the west of Svalbard. During its descent to depths of more than 2000 m the plume entrains three different water masses (East Spitsbergen Water, Atlantic Water, and Norwegian Sea Deep Water) and hence changes its water mass characteristics. The volume of deep water produced by the mechanism discussed here depends not only on the amount of initially formed brine-enriched shelf water, but also on the water mass characteristics of the latter.