The inflow of Atlantic water, heat, and salt to the Nordic Seas across the Greenland-Scotland Ridge

The flow of warm, saline water from the Atlantic Ocean (the Atlantic inflow or just inflow) across the Greenland-Scotland Ridge into the Nordic Seas and the Arctic Ocean (collectively termed the Arctic Mediterranean) is of major importance, both for the regional climate and for the global thermohaline circulation. Through its heat transport, it keeps large areas north of the Ridge much warmer, than they would otherwise have been, and free of ice (Seager et al. 2002). At the same time, the Atlantic inflow carries salt northwards, which helps maintaining high densities in the upper layers; a precondition for thermohaline ventilation. The Atlantic inflow is carried by three separate branches, which here are termed: the Iceland branch (the North Icelandic Irminger Current), the Faroe branch (the Faroe Current), and the Shetland branch (Fig. 1.1). These are all characterized by being warmer and more saline than the waters that they meet after crossing the Ridge, although both temperature and salinity decrease as we go from the Shetland branch, through the Faroe branch, to the Iceland branch. All these branches therefore carry, not only water, but also heat and salt across the Ridge.</p