Mixing and transports in Barrow Strait, the central part of the Northwest passage

Recent hydrographic and current meter data (1981–1983) from Barrow Strait, the central part of the Northwest Passage, are used to determine water mass mixing and long-term mass and heat transports. As surface water moves from the Arctic Ocean to Baffin Bay it loses heat and gains salt in the winter from the growing ice cover. Salty and warmer subsurface water is mixed into the surface layer to various degrees before entering Barrow Strait where three surface water masses of Arctic origin can be identified. The volume transport leaving the Arctic Ocean via Barrow Strait has an annual mean of 0.5 × 10 6 m 3 s −1 and varies seasonally from a minimum of 0.2 × 10 6 m 3 s −1 in January to a maximum of 1.0 × 10 6 m 3 s −1 in August. The heat transported out of the Arctic relative to a reference temperature of −0.1°C, similarly varies from −1.3 × 10 12W in January to −4.0 × 10 12W in August with a yearly mean of −2.4 × 10 12W. The seasonal variations in sea level differences along the Northwest Passage correlate with and can be used to infer the seasonal variations in transports. The results indicate that the transports through the total Archipelago vary seasonally from 0.9 × 10 6 m 3 s −1 and −5.0 × 10 12W in winter to 3.8 × 10 6 m 3 s −1 and −16.7 × 10 12W in summer. These transports contribute significantly to the total volume and heat outflow of the Arctic estimated to be 9.4 × 10 6 m 3 s −1 and −8.8 × 10 13W.