The effects of sea ice on the tides in the Kitikmeot Sea: results using year–long current meter data from Dease Strait and tidal models

Abstract

We examine the tides in the Kitikmeot Sea using year-long time-series from moored instrumentation in Dease Strait, and a 3D barotropic numerical tidal model of the region. The in-situ data show strong tidal damping during wintertime seasonal sea ice cover, with a 50-60% reduction in M2 and K1 tidal elevation and 65% reduction in M2 and K1 tidal velocities at the sea ice maximum. We hypothesize the damping largely occurs in Victoria Strait, the eastern gateway of the Kitikmeot Sea, where tidal-induced ridging causes thick, rough ice to accumulate over its shallow sill. Using the numerical model, FVCOM, we independently vary sea ice friction and sea ice thickness, and show that the observed wintertime tidal damping likely requires both very rough ice and a partial sea ice blockage in the sill region. Analysis of the model shows different dynamics and dissipation of the dominant M2 and K1 tides. Both M2 and K1 tides are dominated by the Atlantic tides entering through Victoria Strait. Arctic tides, entering from the west, have a minor, but significant, contribution to the M2 tide. Overall, the K1 tide, after 19% dissipation in Victoria Strait and 24% in adjoining bays, propagates far into the region and behaves as a Helmholtz resonator in Dease Strait and Coronation Gulf. In contrast, 92% of the M2 tidal energy does not reach Dease Strait because, in addition to dissipation in Victoria Strait (29%), it is significantly diverted into adjoining bays and around an amphidrome in eastern Queen Maud Gulf. The K1 tide, with double the wavelength of the M2 tide, is less diverted.