Ice-Cover and Ice-Ridge Contributions to the Freshwater Contents of Hudson Bay and Foxe Basin

Abstract

Runoff and precipitation add 65 cm of fresh water to Hudson Bay annually. The ice cover does not account for a new contribution of fresh water over a one-year period; however, on weekly time scales, it contributes as much or more than runoff. The maximum thickness of ice averaged over the bay is 160 cm and represents a 140 cm layer of fresh water when sublimation is accounted for. This fresh water is twice as large as the amount annually brought in by runoff and precipitation and is added to the surface layer in the spring and removed from the surface layer in the fall. Freshwater budgets of Hudson Bay and Foxe Basin indicate up to 90% more ice is produced than indicated by ice thickness data. Part of this difference can be attributed to the ice accumulated in ice ridges, which for Hudson Bay accounts for 25 cm of ice and as much as 58 cm of ice for Foxe Basin, where extreme rough ice conditions occur.

Key words: Hudson Bay, Foxe Basin, ice cover, ice ridges, freshwater content