From Rivers to the Ocean: The Dynamics of Freshwater Export from Hudson Strait

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Intellectual Merit: The fresh, buoyant currents which travel along the topographic margins from the polar to the subpolar regions have a profound influence on both the regional and global climate. They also have a strong impact on the ecosystems and fisheries downstream by affecting nutrient supply to the surface layer. Yet our knowledge of how distinct freshwater inputs in the polar basins and coastal regions are transformed into the variable, fresh flow observed downstream is limited. Identifying and understanding the processes that govern this transformation is even more pressing at a time when there is increased freshwater export from the Arctic and models predict an even greater export in the future. The opportunity to study the transformation of a large riverine input, from multiple rivers, combined with the inflow of Arctic freshwater, in a semi-enclosed basin connected to the large scale ocean through a strait is provided by new moored data from Hudson Strait. Hudson Strait is the third largest contributor of freshwater to the North Atlantic and a major contributor of fresh water to the Labrador Current, whose waters influence the shelf-slope waters of the entire northeastern North American coast. Its outflow is strongly varying on daily to interannual timescales. Amongst the potential sources of this variability are the spatially and temporally distributed runoff sources, local forcing and remote atmospheric forcing and variations in the inflow from Davis Strait. The goal of the work proposed is to: (1) identify the processes influencing the freshwater transport on daily to interannual timescales, and (2) determine the relationship between the transport and river run-off, the Davis Strait transport and the Labrador Current transport. These goals will be achieved through the analysis of new and historical moored and hydrographic data from Hudson Strait, complemented by meteorological data, river data and a regional numerical model run by one of our Canadian colleagues. The results from this study will not only improve our knowledge of the freshwater pathways west of Greenland but, also, augment our general understanding of the processes that transform freshwater on its route to the subpolar regions.Broader Impacts: This work is not only of relevance to global climate and to the northeastern North American coast, but it is equally important for the region upstream of the strait which supports a large native population and diverse ecosystem and that has been identified as one particularly susceptible to climate change. The proposed work will foster international collaborations and those across disciplines and bridge the gap between the polar and subpolar regions. The project will involve a post-doc, a U.S. and a Canadian graduate student who will benefit from the exposure to a diverse, international group of scientists. As part of the proposed work we have initiated a collaboration with an accomplished writer with a background in Arctic exploration and Inuit culture. An immediate result of this collaboration is a series of lectures to be conducted in museums around the U.S. that will compare and contrast scientific and geographic exploration by exploiting the 400 year anniversary of Henry Hudson's voyage into Hudson Strait and Bay. Future plans include articles in natural history/popular science magazines and a series of lectures in the Inuit communities along the shores of Hudson Bay and Strait.