North Atlantic deep water (NADW) A water mass (salinity 34.9–35.03 parts per thousand, temperature 1.0–2.5 °C) that was originally believed to form in an area off the southern tip of Greenland, where winter cooling of saline waters was thought to cause a body of water to sink and spread south. It is now recognized that the main source is in the Norwegian Sea, from which deep water flows over the sills between Scotland, Iceland, and Greenland and cascades into the depths of the Atlantic.

North Atlantic deep water (NADW) A water mass (salinity 34.9–35.03 parts per thousand, temperature 1.0–2.5°C) that was originally believed to form in an area off the southern tip of Greenland, where winter cooling of saline waters was thought to cause a body of water to sink and spread south. It is now recognized that the main source is in the Norwegian Sea, from which deep water flows over the sills between Scotland, Iceland, and Greenland and cascades into the depths of the Atlantic.