East Greenland Current - Water Properties

Water Properties

The EGC is composed of a mixture of three distinct water masses. The water masses are Polar Water, Atlantic Water, and Deep Water. These water masses can be clearly seen throughout the EGC's tract southward, however, the upper layer water masses do change some due to atmospheric interaction along with inflow from other water sources in the Nordic Seas. The top 150 meters of the EGC is considered polar water and it is cold and low in salinity. The lowness in salinity has a lot to do with freshwater run off from sea ice melting, river runoff, and Pacific water flux and it is cold due to air-sea interactions while in the Arctic. Typical characteristics for the EGC Polar water are a temperature between 0 °C and –1.7 °C (e.g. freezing point of low-salinity sea water), and the salinity varies greatly from 30 psu (near the surface) to 34 psu at a 150 meter depth. The layer beneath the Polar Water is known as the Atlantic Water layer. It extends down to about 1000 m. This layer is defined as having relatively warm temperatures and saline waters. The temperatures are normally above 0 °C and have a salinity of 34 psu at 150 meters and it increases to about 35 psu at 1000 meters. The Atlantic water that is seen in the EGC comes from two different sources. The first source of Atlantic Water originates from westward directed Atlantic water in the West Spitsbergen Current. This current sends Atlantic water (AW) into the Fram Strait, and because it is more dense then the surface Polar water it sinks to an intermediate depth. The second source of AW in the EGC originates from recirculated AW in the Arctic. This is AW that has entered the Arctic via the North Atlantic and has been circulating in the Arctic and is now being pushed out of the Arctic via the EGC. The layer beneath the Atlantic Water is simply referred to as the Deep Water where the salinity and temperatures are relatively constant. This level typically extends from 1000 meters to the bottom of the ocean. The temperatures in this bottom level are normally below 0 °C and the salinity is around 34.9 psu.

The deep water masses (>1600 m) are recirculated within the Greenland Sea due to the Jan Mayen Fracture Zone. Here, the deep water encounters the Jan Mayen Ridge and are deflected eastward towards the interior of the Greenland Sea Gyre. The upper layers are able to pass into the Iceland Sea unhindered. It is important to note that these recirculated deep water masses in the Greenland Sea Gyre will be recirculated into the EGC once again in the future near Fram Strait.