Evolution of the Arctic Ocean boundary current north of the Siberian shelves

The Arctic Mediterranean Sea is the most important source for the North Atlantic Deep Water, and the Arctic Ocean, often neglected in this respect, may provide a significant amount of the overflow waters crossing the Greenland–Scotland Ridge. Warm water from the south enters the Arctic Ocean through two main passages, Fram Strait and the Barents Sea, and the inward flowing boundary current that overlies the Eurasian continental slope of the Arctic Ocean supplies heat to the Arctic Ocean and exerts a dominant influence over its internal temperature and salinity characteristics. Major transformations of the inflow occur in the Barents Sea and as the two inflow branches meet in the boundary current north of the Kara Sea their characteristics are different. Lateral mixing between the two branches dominates the further transformations of the Atlantic and intermediate layers occurring in the Eurasian Basin. Ice formation, brine rejection and dense water formation on the shelves and subsequent convection down the slope lead to transformation of the boundary current that crosses the Lomonosov Ridge, and determine the properties of the Canadian Basin water column. Changes in the inflow characteristics of the boundary current will gradually, but slowly, affect also the intermediate and deep-water characteristics of the water column in the interior of the Canadian Basin. In the Eurasian Basin the influences of the shelf processes and pure slope convection are smaller and the water mass characteristics are mostly determined by advection and mixing of the two inflows. Only in the deepest part of the water column does slope convection appear to dominate the water mass transformations.