The East Greenland Current and its contribution to the Denmark Strait overflow

Abstract

AbstractThe East Greenland Current is the main conduit for the waters of the Arctic Ocean and the Nordic Seas to the North Atlantic. In addition to low salinity Polar Surface Water and sea ice, the East Greenland Current transports deep and intermediate waters exiting the Arctic Ocean and Atlantic Water re-circulating in the Fram Strait. These water masses are already in the Fram Strait and are dense enough to contribute to the Denmark Strait overflow and to the North Atlantic Deep Water. On its route along the Greenland slope the East Greenland Current exchanges waters with the Greenland and Iceland Seas and incorporates additional intermediate water masses. In 1998 RV Polarstern and RV Valdivia occupied hydrographic sections on the Greenland continental slope from the Fram Strait to south of the Denmark Strait, crossing the East Greenland Current at nine different locations. The Arctic Ocean waters and the re-circulating Atlantic Water could be followed to just north of Denmark Strait, where the East Greenland Current encounters the northward-flowing branch of the Irminger Current. There strong mixing occurs both within the East Greenland Current and between the waters of the two currents. No distinct contribution from the Iceland Sea was observed in the Denmark Strait but the temperature reduction of the warm core of the East Greenland Current just north of the strait could partly have been caused by mixing with the colder Iceland Sea Arctic Intermediate Water. The overflow plume south of the sill was stratified and covered by a low salinity lid. Less saline overflow water was also observed on the upper part of the slope. The less saline part of the overflow was identified as Polar Intermediate Water and its properties were similar to those of the thermocline present in the East Greenland Current already in the Fram Strait. It is thus conceivable that its source is the upper (<0) part of the Arctic Ocean thermocline. Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.Author Keywords: Arctic Ocean, Denmark Strait overflow, East Greenland Current, Nordic Seas, T-S analysis, water masses.