Physical Oceanographic Observations in Baffin Bay and Davis Strait

Abstract

During February 1972, scientific personnel operating from the Louis S. St. Laurent obtained the first winter oceanographic temperature and salinity data from Baffin Bay. Six oceanographic stations were occupied: one in central Baffin Bay; a second in eastern Baffin Bay southeast of the first; and a cross-section of 4 stations in southern Davis Strait .... The temperature and salinity data were obtained using discrete samples from Knudsen bottles, equipped with deep-sea reversing thermometers, and an in situ recording salinity/temperature/depth unit (STD). Temperatures and salinities determined from the discrete water samples were used to calibrate the STD and correct it for drift, while the STD was used to detect fine structure in the vertical distributions of temperature and salinity. ... The temperatures presented ... were those obtained from the reversing thermometers. ... they are presented here in comparison with summer data from the same region .... While it is not possible to draw quantitative conclusions from the small amount of available information, it appears that the deep vertical distributions of temperature and salinity in central and southeastern Baffin Bay and Davis Strait may not undergo significant seasonal variation. Observed near-surface variations may be accounted for qualitatively by a combination of winter cooling, freezing and convective mixing and summer meltwater addition. The apparent constancy of flow through Davis Strait is of particular interest. It has been demonstrated that for sufficient heat to be present in the water column for prevention of ice formation in the open lead in northern Baffin Bay known as the North Water, northerly flow of warm water (>0°C) would have to be greater than observed during the summer months. That this does not appear to be the case strengthens the hypothesis... that the open water is due to a southward advection of ice by winds and currents rather than by heat from the water column preventing formation of the ice.