Description of work packages

Work package 1: Atlantic water pathways. The water mass properties in the Arctic are significantly influenced by the heat and salt supplied by the northward flow of warm Atlantic Water. Its high salinity counteracts the input of freshwater from the continents and the relative fresh seawater entering through Bering Strait. Consequently it affects the stability and the water mass modification in the Arctic Ocean. It reaches the Arctic Ocean either through the Barents Sea opening or through Fram Strait. Deployment of acoustically ranged floats in relatively shallow depth and hydrographic surveys together with a regional model will allow to monitor and understand the spreading of the Atlantic Water into the different pathways.

Work package 2: Fluxes across the western Barents Slope. Part of the northward flow of warm Atlantic Water reaches the Arctic Ocean through Barents Sea. Deployment of moorings and hydrographic surveys together with a regional model will allow to monitor and understand the flow of Atlantic Water into the Barents Sea. In particular the recirculation from the Barents Sea affects the net heat transport significantly.

Work package 3: Heat Flux through Fram Strait. Part of the northward flow of warm Atlantic Water reaches the Arctic Ocean through Fram Strait. Since Fram Strait is the only deep passage to the Arctic Ocean, it plays a significant role in the exchange between the Nordic Seas and the Arctic Ocean. Deployment of moorings and hydrographic surveys together with a regional model will allow to monitor and understand the flow of Atlantic Water into the Arctic Ocean. In particular the recirculation within Fram Strait affects the net heat transport significantly.

Work package 4: Freshwater Fluxes through Fram Strait. Sea ice and Polar Water of low salinity provide the freshwater flux from the Arctic. Deployment of moorings and hydrographic surveys together with a basin scale model will allow to monitor and understand the flow of Polar Water and sea ice from the Arctic Ocean into the Nordic Seas. The techniques to measure the ice-bound freshwater will be further developed to obtain time-series measurements of the salinity profile from underneath the ice to the bottom. They are presently available as a prototype only.

Work package 5: Data Management. The project aims to establish a system which is able to provide data for climate observation as timely as possible to a user community. Therefore transmission of reduced data sets from ships and moorings and input of these data in a network of users will be developed. The final data will be available to the public through the ICES data centre and on CD-ROM.

Work package 6: Integration and Synthesis. The members of the consortium have long-standing experience in high-latitude fieldwork, modelling, data management and data interpretation. Moreover, they are all involved in other Arctic and sub-Arctic programmes. This is mentioned to provide evidence that the data synthesis will be carried out not only within the specific frame of the project but also within the wider context of arctic-subarctic exchanges. The synthesis will comprise:

• Reviewing the observations from this and earlier projects with respect to the relationship of fluxes through the individual passages, upstream oceanic and sea ice conditions, and atmospheric forcing.
• Establishing the reliability of models to reproduce the observed variability of fluxes.
• Using model experiments and observations to generate an improved overall understanding of the exchanges between Arctic Ocean and Nordic Seas.
• Designing an optimised monitoring array for long-term measurements of heat and freshwater to become a contribution to an ocean observing system.