Atlantic Ocean Leakage/Rings, which brings salty Indian Ocean waters into the South Atlantic, and the "Atmospheric Bridge", which evaporates subtropical Atlantic waters and exports it to the Pacific. The Atlantic Ocean consists of four major, upper water masses with distinct temperature and salinity. The Atlantic Subarctic Upper Water in the northern-most North Atlantic is the source for Subarctic Intermediate Water and North Atlantic Intermediate Water. North Atlantic Central Water can be divided into the Eastern and Western North Atlantic central Water since the western part is strongly affected by the Gulf Stream and therefore the upper layer is closer to underlying fresher
Overturning in the Subpolar North Atlantic Program of heat, mass and freshwater for a comparison to records of convective activity and water mass transformation at high latitudes in the North Atlantic. The OSNAP observing system, fully deployed in the summer of 2014, consists of moorings, gliders and RAFOS floats spanning the subpolar North Atlantic from Labrador to Greenland to Scotland. Measurement contributions come from the US, the UK, Germany, the Netherlands, Canada, China and France. Vigorous boundary currents crossing the OSNAP line are directly measured in the Labrador and Irminger Seas by current meter arrays, and over the eastern flank of the Reykjanes Ridge by deep arrays.