Claudia Cenedese (email@example.com), Woods Hole Oceanographic Institution
The Canadian Basin with its Beaufort Gyre (BG) contains about 45,000 cub. km of fresh water [Aagaard and Carmack, 1989]. This is the major reservoir of fresh water stored in the Arctic Ocean and its volume is 10--15 times larger than the total annual river runoff to the Arctic Ocean, and at least two times larger than the amount of fresh water stored in the sea ice. What is the mechanism of fresh water accumulation in the BG? A release of only 5% of this fresh water is enough to cause a salinity anomaly with the magnitude of the Great Salinity Anomaly of the 1970s. This leads to other questions: What is the seasonal and interannual variability of freshwater content in the BG? and What is the role of the BG in the variability of freshwater export to the North Atlantic? There are no robust answers for these questions because the BG is one of the most hostile and inaccessible areas of the globe, so that most of it has never been measured or observed. The major goal of this project is to investigate basin-scale mechanisms regulating freshwater content in the Arctic Ocean and particularly in the BG. The major hypothesis of the project is that the BG accumulates a significant amount of fresh water from different sources under anticyclonic (clockwise) wind forcing, and then releases this fresh water when this forcing weakens or changes direction to a cyclonic (counterclockwise) rotation. This accumulation and release mechanism could be responsible for the observed salinity anomalies in the North Atlantic and for a decadal scale variability of the Arctic system as the BG may both filter annual river inputs and pulse freshwater outflows.
We propose to: (1) establish an observational program to measure freshwater content (in sea ice and in the ocean) and freshwater fluxes in the BG using moorings, drifting buoys, and remote sensing; (2) analyze all available historical data for the area using Russian, US and international data archives; and (3) model processes of freshwater accumulation and release using ideal and real-time numerical models.
Based on analyses of historical data, direct observations, and results of specially designed numerical experiments, we propose to further our understanding of the Arctic climate system by (1) identifying links among accumulation and release of fresh water in the BG and atmospheric, hydrologic, cryospheric and oceanic processes, (2) quantifying the regional and temporal variability of relevant processes in terms of freshwater fluxes, and (3) determining the relative importance of each factor that influences freshwater content and flux change under global warming conditions. The observed freshwater content variability in the BG, which acts to integrate the complex contributions from different factors, is expected to be the primary indicator of the ocean's response to climate change.
The proposed research and results of this project will have a direct influence on the ASOF, CHAMP, and SEARCH programs and other projects through data exchange, reporting, and participation in their meetings and workshops.
Science Management Office
Role of the Arctic-CHAMP Science Management Office