Long-term changes in the characteristics and circulation of deep waters in the northern North Atlantic: The role of regional and external factors

Large scale circulation in the northern part of the Atlantic Ocean is one of the main elements in the cli matic system of the Earth. The North Atlantic Current transports warm subtropical waters in the upper ocean. In the Subarctic Atlantic and Arctic basin (Fig. 1), these waters transfer heat to the atmosphere and become cooler and denser. They mix with the cold Arctic waters and descend to the depths forming a flow of cooler and denser deep waters directed to the low latitudes [1, 2]. Heat transport to the north (up to ~1 1015 W [1]) is associated with this circulation known as the Meridional Overturning Circulation (MOC) in the North Atlantic.