The Role of the Nordic Seas in Promoting Deep Water Formation in the Northern Hemisphere

An ocean GCM is used in an idealized setting to examine the role of the basin latitudinal extent on promoting deep water formation in the northern Atlantic. Most of the debate over what causes this deep water formation has focused on the role of different salinity concentrations in the Atlantic and the Pacific. Here, it is emphasized that temperature differences are another important aspect of the problem using simulations of an ocean with two basins with areas equal to those of the Atlantic and Pacific Oceans. The simulations are forced with somewhat realistic winds and are restored to a latitudinally symmetric atmospheric temperature. Deep water formation through convection in the northern hemisphere is localized in the basin that extends further north, be it the small Atlantic-like basin or the Pacific-like basin. We interpret these results as evidence that deep water formation in the Atlantic Ocean is favored not only by its higher salinities, but also by its connection to the Nordic Seas which are exposed to colder temperatures than the North Pacific.