Wind-driven Transport in the Labrador Current

Relative importance of density and wind in generating the Labrador Current and the roles of local vs. remote wind forcing have not been conclusively resolved. In this study the wind-driven transport of the Labrador Current is investigated using finite-element ocean circulation models and NCEP-NCAR wind data for the 1990s. Long-term monthly-mean and individual seasonal-mean wind-driven circulation is computed with the NCEP-NCAR wind stresses prescribed at the sea surface and sea levels specified at the open boundary determined from a North Atlantic model. The annual-mean model solutions clearly show wind-driven equatorward inshore, shelf-edge, and deep-ocean branches of the Labrador Current. There are strong seasonal variations in the branches of the Labrador Current with the largest in December-February and smallest in June-August. The interannual changes are also significant in the 1990s, with the winter transport in positive correlation with the wind stress curl associated with the Icelandic Low. The model shelf-edge and deep-ocean Labrador Current is dominated by the remote forcing, while the local wind forcing plays an important/dominant role in the inshore current. Role of wind-driven currents is evaluated, which indicates that the wind forcing contributes significantly to the inshore branch and substantially to the shelf-edge branch.