Hydrographic observations in Denmark Strait in fall 1997, and their implications for the entrainment into the overflow plume.

Denmark Strait is the most important exit for water masses formed in the Ar ctic Mediterranean Sea and supplies a substantial fraction of the North Atl antic Deep Water. Observations obtained from RV Aranda in August-September 1997 indicate that the water crossing the 620m deep sill is mainly drawn fr om the intermediate waters of the East Greenland Current. The overflow plum e was stratified and capped by a less saline layer as it descended beyond 2 000m. The presence of a low salinity lid implies that entrainment of ambien t water is small and that the downstream evolution of the plume characteris tics is due to mixing, within the plume, between the initial overflow water s. Low salinity, but dense, water from the East Greenland Current flowing o ver the shelf may cross the shelf break south of the sill and add a less de nse fraction to the overflow.