Structure and transports of the East Greenland Current at 75°N from moored current meters

Abstract

The East Greenland Current runs from 80°N to 60°N from the Fram Strait to the Denmark Strait via the Nordic Seas. It transports waters from the Arctic and the Nordic Seas into the Atlantic and also acts as a western-intensified southward return flow for waters recirculating within the Greenland Sea Gyre, itself an area important for deep water formation. Data from current meters moored across the current at 75°N in 1994-1995 show a large seasonal variation in the current. The annual mean transport is 21 ± 3 Sv (taking 9°W as the eastern boundary), varying from 11 Sv in summer to 37 Sv in winter (errors approximately ± 5 Sv). No significant seasonal signal has been observed in the Fram or Denmark Straits, suggesting that the seasonal transport is confined within the Greenland Sea. Using temperature and velocity data, we split the flow at 75°N into two parts, a mainly wind-driven circulation (annual mean of order 19 Sv), which is trapped within the Greenland Sea Gyre and exhibits a large seasonal cycle, transporting, predominantly, the waters of the Greenland Sea, and a steadier throughflow probably thermohaline-driven (of order 8 Sv in the annual mean), with very little seasonal variation. Data from previous years, 1987-1994, indicate the interannual variability of the current is low. Assuming a spatially coherent structure to the current, we extend the time series of the transport back to 1991, and suggest it may be possible to monitor the total transport with one suitably placed mooring. Copyright 1999 by the American Geophysical Union.