Collaborative Research: Circulation in the Freshwater Switchyard of the Arctic Ocean

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The proposed research will document the circulation, variability, and driving mechanisms of the upper ocean in the freshwater switchyard of the Arctic Ocean. This unexplored region lies to the north of the eastern Canadian Archipelago and Greenland, extending about 500-800 km into the central Arctic Ocean. It lies just upstream of the freshwater exit points in Fram and Nares Straits, i.e., where freshwater from various sources is finally delivered to some of the main channels that lead to the North Atlantic Ocean. The main hypothesis is that this area is a bifurcation point for freshwater transfer between the Arctic and North Atlantic Oceans, and that small changes in the overall circulation of this region may have large downstream effects. This study will measure ocean temperature, salinity, currents, and geochemical freshwater tracers such as oxygen, oxygen isotopes, tritium/3He, CFC.s, barium, and nutrients. The focus will be on the upper ocean (0-300 m) where freshwater resides. This will be an aircraft-based operation, because thick sea ice prevents access by most surface ships and political realities prevent access by submarine. There will also be a satellite-based study of sea ice motion and thickness in the switchyard region which will determine how much ice recirculates westward within the Beaufort Gyre, how much exits through Fram Strait, and how much exits within the various passages of the Canadian Archipelago. Results from this study will be made available via an internet web site that will be linked to other similar ongoing projects, as well as through presentations and articles in both scientific and popular formats. Additionally, they will be used for educational purposes through involvement of both graduate and undergraduate students, and in course material. A special link to numerical modeling studies is planned via incorporation of our data into a gridded ocean database as well as raw validation data. The appropriate logistics infrastructure at NSF has been developed over the past several years as part of various projects, in particular the North Pole Environmental Observatory, an aircraft-based project staged out of Alert/Eureka.