The semi-diurnal tide in Hudson Strait as a resonant channel oscillation

Abstract

Tidal studies have shown that there exists a resonance of the semi-diurnal tide in the Hudson Bay-Hudson Strait system. The resonant response is particularly strong within Hudson Strait and Ungava Bay. It is shown here that the semi-diurnal tide in Hudson Strait has characteristics that are similar to those of a half-wavelength open channel resonance. A simple analytical model is developed to account for the salient aspects of the semi-diurnal response in the strait. Non-dimensional parameters that govern the response are identified and evaluated based on the physical dimensions of the region and results from a numerical tidal model. Taking account of the mechanical impedance presented to the channel by Hudson Bay, the results suggest that a channel mode is resonant near semi-diurnal periodicities, in general agreement with observations and more complex tidal models of the region. The possibility that Ungava Bay may have a separate quarter-wavelength resonance driven at the entrance to the continental shelf is also briefly explored.