Patrick Eriksson

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 Arctic Mediterranean Sea and supplies a substantial fraction of the North Atlantic Deep Water. Observations obtained from RV Aranda in August-September 1997 indicate that the water crossing the 620m deep sill is mainly drawn from the intermediate waters of the East Greenland Current. The overflow plume was stratified and capped by a less saline layer as it descended beyond 2000m. The presence of a low salinity lid implies that entrainment of ambient water is small and that the downstream evolution of the plume characteristics is due to mixing, within the plume, between the initial overflow waters. Low salinity, but dense, water from the East Greenland Current flowing over the shelf may cross the shelf break south of the sill and add a less dense fraction to the overflow.

Constraints on Estimating Mass, Heat and Freshwater Transports in the Arctic Ocean: An Exercise

The ASOF programme, with its study of the transports between the Arctic Ocean and the North Atlantic via the subarctic seas – the Nordic Seas, Baffin Bay and the Labrador Sea –, also provides an opportunity to examine the mass (volume), freshwater and heat budgets of the Arctic Ocean. The exchanges between the two passages between the Arctic Ocean and the Nordic Seas, Fram Strait and the Barents Sea opening between Norway and Bear Island, have been measured continuously since 1997, first in the VEINS programme (Variability of Exchanges in the Northern Seas) and then in ASOF and the observations are presently continued within the DAMOCLES (Developing Arctic Modelling and Observing Capabilities for Longterm Environmental Studies) programme. The transports through two of the three main channels in the Canadian Arctic Archipelago, the Lancaster Sound and the Jones Sound, have been directly measured for a couple of years now (Prinsenberg and Hamilton 2005), and the instruments from the first year-long measurements in Nares Strait have been brought in. The fluxes through Bering Strait have also been studied intensely the last 10–15 years (e.g. Woodgate and Aagaard 2005). The work within ASOF has shown that the transports through Fram Strait and through the Canadian Arctic Archipelago are those most difficult to determine. The Archipelago because of the severe climate, the remoteness of the area and the nearby location of the magnetic North Pole, Fram Strait because of its depth, the transports in both directions, and the presence of baroclinic and barotropic eddies leading to high spatial and temporal variability. The estimates of the mean transport through Bering Strait obtained since the mid-1980s have ranged around 0.8 Sv (1 × 10 m s), but large seasonal variations have been reported, 1.2 Sv in summer and 0.4 Sv in winter (Coachman and Aagaard 1988; Woodgate and Aagaard 2005). The mean transport of Atlantic water to the Arctic Ocean through the Barents Sea opening has been estimated to 1.5 Sv from

Digital, high resolution weather, sea ice and ocean information to the users at sea: the IWICOS demonstration during the Aranda expedition in the Fram Strait

Abstract One of the major bottlenecks in marine information distribution from the producers to the users at sea is a lack of suitable systems. In March 2002 the IWICOS system was demonstrated in the Fram Strait, an area with limited communication possibilities, and where the environment plays a vital role. The Iridium satellite system was used for data transfer. The number and file sizes of delivered information were minimal. The system operated satisfactory and the user feedback was positive.