At the Bering Strait, three years of current, temperature and salinity measurements from moorings are used to calculate the analagous source, which mainly represents runoff from rivers along the gulfs of Alaska and Anadyr. The fresh-water has been run as a "passive" tracer, in which case it plays no role in the equation of state. In these experiments, the fresh-water is a simple dye, which tags each of the shelf regions with a different "color", and the salinity forcing at the surface is by relaxation toward the Levitus climatology. Alternatively, some experiments were done with the runoff included in the density calculations, in which case a very weak relaxation is used to prevent climatological drift (and, presumably, to make up for missing terms such as local precipitation and permafrost erosion).
Three preliminary model experiments have been conducted so far, and compared with the tracer observations. The comparisons are highly encouraging. The modeled tracer distributions show the strong topographic guidance for which the Arctic is so well known. Distribution of tracer with depth is in excellent agreement with the observations, with increases of vertical penetration over the ocean ridges. Deep vertical convection is visible in several of the locations where we believe that density plumes do, in fact, flow down the shelf-front into the deep basins. One advantage of the high resolution aad scale of the model is that it can capture the flow of buoyance through the Canadian Arctic Archipelago and trace its properties back to their source.
The model results and tracer transects will be presented, along with a few relevant points regarding findings from other shelf-related studies we are conducting.
