Circulation and watermasses in the Davis Strait

The Davis Strait represents a potentially critical upstream boundary for North Atlantic deep water formation and is an essential site for monitoring the total freshwater exchange between the Arctic and lower latitude basins. Southward fluxes through the strait embody the integrated outflow from the Arctic through the Canadian Archipelago, modified by terrestrial inputs and oceanic processes during its southward transit through Baffin Bay. Measurements collected during the first year of a three-year program employing moorings, hydrographic sections and acoustically navigated gliders characterize circulation and water mass variability across the strait including, for perhaps the first time, year-long records over the shallow shelves. Comparisons of 2004 and 2005 hydrographic sections with autumn climatology (1928 -- 2004) reveal warmer (~ 1°C), more saline (0.15) conditions associated with Atlantic inflow spreading across the strait, well west of the Greenland slope. High-resolution sections between the strait's 400 m isobaths, occupied by an autonomous glider, reveal significant deformation-scale (tens of kilometers) variability, while moorings across the shallow shelves suggest that they contribute significantly to volume, freshwater and heat fluxes. Initial calculations of volume transport show a net southward flow which is in agreement with previous studies, though smaller in magnitude. Southward fluxes dominate the strait's western half, with northward flow over the broad Greenland slope and shelf. However, aliasing of observed small-scale recirculation by the moored array imposes relatively large uncertainties.