Scientific background and intentions
The Norwegian Atlantic Current (NwAC) through the Norwegian Sea serves as a conduit of warm and saline Atlantic water from the North Atlantic to the Barents Sea and Arctic Ocean. The North Atlantic Current (NAC) enters the Norwegian Sea over the Greenland-Scotland Ridge (GSR), and after crossing the ridge it is established as the two-branch Norwegian Atlantic Current (NwAC). The NwAC then continues as a two-branch current through the Norwegian Sea toward the Arctic. The western branch is a jet in the Polar Front through the interior of the Norwegian Sea toward the Fram Strait, while the eastern branch is a barotropic shelf edge current along the Norwegian shelf that tends to flow into the Barents Sea and Arctic Ocean (Orvik and Niiler, 2002). The Svinøy section cuts through the entire Atlantic inflow (AI) just to the north of the GSR (Orvik et al., 2001) and is as such a suitable place to undertake a comprehensive monitoring of the NwAC, as up-stream reference for the Arctic Ocean. Through the proposed instrumentation in Task 1.1 in combination with ongoing measurements (Damocles), we now aim to establish an up-stream bench-mark for the AI toward the Arctic in the SS, both with respect to variability of fluxes and water mass properties. In light of that, the following approaches appear to be relevant: How can observations in the SS be traced downstream toward the Arctic, and how can we take advantage of striking events observed in the SS for prediction of future changes in the Arctic?

1. Variations determined from satellite altimeter observations of the eastern NwAC, show a coherent structure along the Norwegian shelf break from Scotland to the Barents Sea opening and West Spitsbergen (Skagseth et al., 2004). Through this project, we will have an opportunity to take advantage of these findings in comparing along-slope volume transports toward the Fram Strait.

2. In a recent paper Polyakov et al. (2005) showed that a warm event observed in the SS was traced to higher latitude regions with a 1.5 year time lag to the Farm Strait and additionally about 5 years to reach the Laptev Sea in the Arctic. Presumably, this event is related to water masses associated with the eastern NwAC. Through this project, we aim to develop further our understanding of the processes behind the propagation of these signals. Are they related to the flow field directly, does eddy shedding into the interior Norwegian Sea through instabilities play a major role? And finally, how robust and applicable are the observations in the SS for perditions of future events in the Arctic Ocean

3. The western branch of the NwAC follows the Polar Front through the interior of the Norwegian Sea toward the Fram Strait and Arctic. The transformation of the Atlantic water along its pathway is not well known, but it becomes cooler and fresher toward the Fram Strait. Through this project with extensive use of gliders and standard hydrographic observations, we will concentrate on improving our understanding of the water mass transformation in the Norwegian Sea. Are they mainly related to the major pathways, or does the interaction with surrounding water play an important part.

4. By deploying an observation system in the western NwAC in SS, we aim to establish a reference-system with respect to fluxes in the Polar Front.  Through extensive use of gliders and moored observations e.g. at Station M and in the Fram Strait, we intend to improve our understanding and connection of the evolution of downstream fluxes through the Norwegian Sea, and the division between recirculation and inflow to the Arctic in the Fram Strait

5. Furevik (2001) found examples of anomalies that were both locally generated and propagating with the direction of the current. Further the propagation of the Great Salinity Anomaly as an advective signal is described in Dickson et al. (1988). However, the interpretation of Dickson et al. (1988) has recently been challenged by Sundby and Drinkwater (2006). They point instead toward the combined effect of variations in the current speed and along-current salinity gradients. The improved measurements of both hydrography and currents in the NwAC provide an opportunity to investigate the characteristic of anomalies and their propagation in more detail.