Tidal Currents and Inertial Oscillations in Northwestern Baffin Bay

Abstract

From moored current meter data obtained in 1978 and 1979 in western Baffin Bay and Lancaster Sound, a preliminary analysis was made of the tidal currents and interial oscillations in the area. The tidal currents are relatively small through much of the study area. Offshore, the largest of both the diurnal and the semi-diurnal tidal currents were in all cases less than 8 cm/s in amplitude. In nearshore locations, the tidal currents can be considerably stronger due to internal tides; for example, off Cape Hay on Bylot Island, the K1 tidal currents near the surface were determined to have an amplitude of 15 cm/s. Evidence of inertial oscillations was present in the records from the uppermost current meters on all moorings located at a nominal depth of 35 m. Typical amplitudes were 10 to 20 cm/s, with speeds as high as 35 cm/s being observed. The magnitude of inertial oscillations decreases rapidly with depth; at 250 m, they are greatly reduced in amplitude and are difficult to resolve from the semi-diurnal tidal currents. The inertial oscillations resulted, in large part, from changes in the local surface wind; at times of solid ice cover, their amplitudes were markedly reduced.

Key words: Baffin Bay, tidal currents, inertial oscillations, circulation