Subpolar mode water classes in the northeast Atlantic: Interannual and long-term variability

Abstract

We distinguish the classes of Subpolar Mode Waters (SPMWs), calculate their long-term characteristics, and analyze their interannual and long-term variability based on data from the transatlantic section along 59.5° N measured in 2002–2016. The branches of the North Atlantic Current are horizontal boundaries of the SPMW classes. Modern cooling and freshening of SPMW cores are revealed due to the increased winter atmospheric circulation over the North Atlantic and decline of the Arctic ice cover. In 2010–2016, the potential temperature of the SPMW core in the Iceland Basin dropped by 2.12°C, while its salinity decreased by 0.23 psu.