Deep water exchange in Fortune Bay, Newfoundland

Abstract

Temperature, salinity and density data are presented showing a seasonal cycle in the deep water in Fortune Bay, Newfoundland. Cold Labrador Current Water flows in from Saint-Pierre Channel, an extension of the Avalon Channel, in the summer. Warm Modified Slope Water flows in from Hermitage Channel in the winter. -- A description of the water structure in the Fortune Bay area for 1981 and 1982 is presented. The transport of the Labrador Current in the Saint-Pierre Channel is determined to be 6.4 x 10⁴ m³ s⁻¹. Cold water exchange in the summer is found to be correlated with a seasonal variation in the Labrador Current flow. Direct current meter measurements of this density current inflow are provided with an analytical discussion of the interaction between the flow and the tide. -- Warm water exchange in the winter is found to be correlated with a seasonal shift in the wind stress. Light southwesterly summer winds are replaced in winter by strong northeasterly winds. Two possible mechanisms by which the wind can generate the Modified Slope Water inflow are put forward: a time-dependent upwelling model and a steady-state upwelling model.