The oceanography of the northern subregion is greatly influenced by cold and low salinity polar water originating from the Arctic Ocean, which occupies the upper layer of the East Greenland Current and covers a large part of the surface waters of the shelf (Figure 12). In the southern subregion, warmer and more saline Atlantic waters, originating from the Irminger Current, are prevalent, with the polar waters being constrained to the relatively narrow coastal region on the shelf (Figure 12).
The northern subregion is dominated by an inflow of sea ice from the Central Arctic Ocean, with maximum and minimum coverage occurring in March and September, respectively. In the winter, there is near total sea ice coverage except for polynyas (an area of open water surrounded by sea ice). In the southern subregion, drift ice is seasonally (early spring) imported from the northern subregion via the East Greenland Current.
Figure 12: General pattern of the surface ocean circulation (depth range 0–1000 m) and relative sea surface temperature in the Greenland Sea ecoregion and adjacent areas. Green arrows represent cold currents from the polar region and red arrows warm currents from the Subpolar Gyre (RAW: Recirculating Atlantic Water; JMC: Jan Mayen Current; EIC: East Icelandic Current; NIIC: North Icelandic Irminger Current; WNAW: West North Atlantic Water; ENAW: East North Atlantic Water).