Fate of Freshwater and Heat in Baffin Bay: Basin-scale Circulation and Shelf/slope Processes

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Due to the warming climate the Arctic pack-ice is melting at a fast rate, and some models predict that, in just a few decades, the Arctic will be ice-free during the summer months. At the same time, the Greenland ice sheet is undergoing accelerated ice loss, which is largely due to warm ocean waters from the south melting the undersides of the glaciers surrounding the coast. Two important questions associated with this are: (1) What is the ultimate fate of the increased meltwater? and (2) How are the warm waters able to get so close to the coast of Greenland? In fall of 2021, a detailed shipboard survey of the circulation and water characteristics in Baffin Bay (on the western side of Greenland) was carried out on the US Coast Guard Cutter Healy. In this project we will analyze the data collected on the Healy to address the two questions above. We will combine our shipboard information with data collected by a small, self-propelled underwater vehicle that was able to sample closer to the coast than the Healy could. We will also use recent and past data collected by other ships and will use output from a very detailed numerical model to complement our observations. The project will advance our understanding of how the circulation and wind forcing help dictate where the surface meltwater goes and how the subsurface warm waters are steered shoreward. The project will fund a young researcher to work with the principal investigators. We will share our results with indigenous communities on Baffin Island and organize a scientific workshop at the Greenland Institute of Natural Resources.During the past few decades, the amount of freshwater in the Arctic Ocean has been increasing substantially and the mass loss from the Greenland ice sheet has been accelerating. Much of the freshwater exiting Fram Strait (between Greenland and Svalbard), and most of the meltwater from Greenland, ends up in the boundary current encircling Greenland. Furthermore, beneath the surface layer in the current resides the warm and salty subtropical-origin water that has been implicated in causing basal melt in Greenland’s glaciers. In autumn 2021 the USCGC Healy carried out an extensive hydrographic/velocity survey of Baffin Bay. This project will use these data to address the fate of heat and freshwater in the bay. In addition to the Healy data, we will use contemporaneous glider data and shipboard data from the CCS Amundsen, as well as historical hydrographic data and output from a very high-resolution numerical model. The project will fundamentally advance our understanding of (1) the evolution of the boundary current system as it encircles Baffin Bay; (2) the mechanisms by which heat is transferred from the west Greenland boundary current to glacial fjords via deep troughs in the continental shelf; (3) the partitioning of freshwater between Arctic-origin and Greenland meltwaters and how these two components are distributed in the bay; and (4) the general circulation and hydrography of Baffin Bay, including its seasonality. Researchers from six foreign institutions are involved in the project. A postdoctoral investigator will work with the team of investigators. For outreach we will engage community members and stakeholders during a trip to Baffin Island, and we will organize a scientific workshop at the Greenland Institute of Natural Resources.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.