The Irminger Sea a particularly complex area of the western North Atlantic where a host of important processes occur. It is where the final transport of the dense water overflow from the Nordic Seas is established, it is a site of intermediate mode water formation, and it is where freshwater of Arctic origin gets fluxed off the boundary into the open Atlantic. All of these things impact the North Atlantic subpolar gyre, with ramifications for the global overturning circulation. Understanding how each of these processes work, and their relationship to one another, will enable us to better understand an important piece of the North Atlantic climate puzzle.
In 2001-2004 an NSF-sponsored field program was carried out in the Irminger Sea to document the occurrence of open-ocean convection in mid-basin, and investigate the evolution of the boundary current system from Denmark Strait to the southern tip of Greenland. The experiment included moored conductivity/temperature/depth profilers in the interior, and high-resolution shipboard hydrographic/ADCP surveys of the boundary current system. From the initial analysis of these unique data , together with historical measurements and the use of oceanographic and atmospheric models, a variety of new and important ideas have emerged with respect to this important area of the ocean. This includes new modes of ocean-atmosphere interaction leading to interior convection, and heretofore undetected boundary current processes leading to shelf-basin exchange. This proposal seeks funds to carry out the analysis phase of this project. A set of studies is described, each with its own hypothesis, that will significantly advance our understanding of convection and subpolar mode water formation, as well as the mechanisms and dynamics governing the offshore flux of mass and properties into the western North Atlantic.
Intellectual Merit: New and important means by which the atmosphere interacts with the subpolar ocean will be elucidated in this project, as well as the dynamics of coastal and shelfbreak currents that link the Arctic and sub-Arctic domains and help dictate the lateral transfer of properties from shelf to basin.
Broader Impacts: This project will help us understand the important role that the Irminger Sea plays in the ventilation, stratification, and freshwater budget of the North Atlantic subpolar gyre. This in turn has important ramifications for the global meridional overturning circulation, including the manner in which this system might respond to climate change.
