The West Greenland Current (WGC) flows north along the shelf and shelf break of the west coast of Greenland. It transports about 3 Sv of fresh (salinity < 34.5), cold (-1.8°C) water from the Nordic seas (Clarke 1984; Cuny et al. 2002). The WGC also transports small icebergs north of 60°N, and primarily north of 70°N it transports large icebergs off the West Greenland Shelf into Baffin Bay. Many icebergs are transported south, through the Davis Straits, by the Labrador Current and either recirculate in the Labrador Sea or end up melting in the North Atlantic shipping lanes.
The West Greenland Current as represented by the Mariano Global Surface Velocity Analysis (MGSVA). Its source water is primarily from the East Greenland Current, and it feeds the Labrador current. The West Greenland Current is an important component of the North Atlantic subpolar gyre. Click here for example plots of seasonal averages.
Cuny et al. (2002) used both Eulerian and Lagrangian data to study the WGC. Their Eulerian data showed that the approximate speed for the shallow WGC was 35 cm s-1. It also showed that there were countercurrents with speeds of about 3 cm s-1 offshore the main current. Lagrangian data supported this finding. Five drifters deployed on the WGC were traveling northwestward when they left the boundary current and moved southeastward. The drifters changed directions at different times and at different places between 59° and 61°N. After staying in the countercurrents for a few days, the drifters began heading toward the interior of the Labrador Sea. Cuny et al. did not observe a complete recirculation loop in any of the drifter trajectories.
Unlike the Eulerian data, the Lagrangian data showed that the maximum speed for the WGC at Cape Desolation is 95 cm s-1 at the 2000-m isobath. The current is slower on either side of the 2000-m isobath; above the shelf, it flows at about 35 cm s-1, and close to the 3000-m isobath it flows at 25 cm s-1. As the water reaches the transition area between the Greenland and Labrador slopes, the current has, on average, half the speed of the shallow WGC. When it reaches the shoaling depths off Greenland, the current bifurcates. Part of the current continues to flow along the Greenland coast, and the rest proceeds westward to join the Labrador Current (Cuny et al. 2002).
The branch of the current that follows the Greenland coast does so until about 75°N. It then crosses Baffin Bay and joins waters from the Canadian Arctic Archipelago to form the southward Baffin Current (Loder et al. 1998; Melling et al. 2001). Thus, the WGC and the Baffin Current form a cyclonic circulation pattern (Melling et al. 2001) that can be seen in hydrographic observations (Muench 1971, Bourke et al. 1989), in the tracks of drifting icebergs and buoys (Fissel et al. 1982; Marko et al. 1982), and in long-term measurements of the currents (Ross 1990a, b, 1991).
The branch of the WGC that joins the Labrador Current has shown the most variability. It is most variable near the shelf break between Greenland and Labrador, due to eddies and/or shelf waves of about 30 km in size that last for several days (Meyers et al. 1989). In addition to eddies, the WGC also exhibits variability in its salinity. Dickson et al. (1984) described a "great salinity anomaly" in the early 1970s. Myers et al. (1989) measured salinity anomalies in the Labrador Sea that were similar in strength to those that Dickson et al. had found, and they concluded that the anomalies apparently occur on a decadal time scale. Variabilities in transport have also been observed. Myers et al. (1989) found that strong winter westerly winds implied weakened shelf break fronts and lower baroclinic transports the following summer. This inverse relationship was consistent throughout the Labrador Sea and may be an important part of the interannual variability of the region.
Bourke, R.H., V.G. Addison, and R.G. Paquette, 1989: Oceanography of Nares Strait and northern Baffin Bay in 1986 with emphasis on deep and bottom water formation. J. Geophys. Res., 94, 8289-8302.
Clarke, R.A., 1984: Transport through the Cape Farewell-Flemish Cap section. Rep. 1984, pp. 120-130, Int. Counc. for the Explor. of the Sea.
Cuny, J., P.B. Rhines, P.P. Niiler, and S. Bacon, 2002: Labrador Sea boundary currents and the fate of the Irminger Sea Water. J. of Phys. Ocean., 32, 627-647.
Dickson, R.R., J. Meincke, S.A. Malmberg, and A.J. Lee, 1984: The great salinity anomaly in the northern North Atlantic, 1968-82. Progress in Oceanography, 20103-151.
Fissel, D.B., D.D. Lemon, and J.R. Birch, 1982: Major features of the summer near-surface circulation of western Baffin Bay, 1978 and 1979. Arctic, 35, 180-200.
Loder, J.W., G. Gawarkiewicz, and B. Petrie, 1998: The coastal ocean of northeastern North America (Cape Hatteras to Hudson Strait). In: The Sea: Ideas and Observations on Progress in the Study of the Seas. Vol. 11: The Global Coastal Ocean: Regional Studies and Syntheses. A. Robinson and K. Brink (Eds.) John Wiley and Sons Inc., Toronto, 1062 pp.
Marko, J.R., J.R. Birch, and M.A. Wilson, 1982: A study of long-term satellite-tracked iceberg drifts in Baffin Bay. Arctic, 35, 234-240.
Melling, H., Y. Gratton, and G. Ingram, 2001: Ocean circulation within the North Water Polynya of Baffin Bay. Atmosphere-Ocean, 39, 301-325.
Muench, R.D., 1971: The physical oceanography of the Northern Baffin Bay Region. AINA Research Paper No. 1. The Arctic Institute of North America, University of Calgary, Calgary, Alberta, Canada. 150 pp.
Myers, R.A., J. Helbig, and D. Holland, 1989: Seasonal and interannual variability of the Labrador Current and West Greenland Current. ICES C.M. 1989/C:16, 10 pp.
Ross, C.K., 1990a: Currents and temperature data from northwestern Baffin Bay, September 1983 - September 1984. Canadian Data Report of Hydrography and Ocean Sciences No. 78. Fisheries and Oceans Canada, Bedford Institute of Oceanography, Dartmouth, N.S. viii, 227 pp.
Ross, C.K., 1990b: Currents and temperature data from northwestern Baffin Bay, October 1984 - October 1985. Canadian Data Report of Hydrography and Ocean Sciences No. 79. Fisheries and Oceans Canada, Bedford Institute of Oceanography, Dartmouth, N.S. vii, 180 pp.
Ross, C.K., 1991: Currents and temperature data from northwestern Baffin Bay, October 1985 - August 1986. Canadian Data Report of Hydrography and Ocean Sciences No. 95. Fisheries and Oceans Canada, Bedford Institute of Oceanography, Dartmouth, N.S. vii, 161 pp.