Award: OCE-2038481

The SNAP-DRAGON (Subpolar North Atlantic Processes – Dynamics and pRedictAbility of Gyre and OverturNing) project involved scientists across 5 UK and 5 US institutions. Its primary aim was to establish what determines ocean circulation and properties in the subpolar North Atlantic, using a combination of observations, models and model-data products (reanalyses). This is of particular interest because the subpolar North Atlantic is where waters become dense as part of the Atlantic Meridional Overturning Circulation and fill the deep North Atlantic. Here we focus on the US contributions enabled by this award, which spanned analysis of Overturning in the subpolar North Atlantic Program (OSNAP) mooring observations as well as a variety of ocean models.

The observational component of this work led to a deeper understanding of how much freshwater from the Arctic gets mixed into the deep North Atlantic. We found that about half of the Arctic freshwater east of Greenland gets mixed into the AMOC’s lower limb. Another analysis found that winds blowing southward along the east coast of Greenland can cause deep mixing in the along-shore current, which had not been previously known. This project sparked a collaborative project with a Ph.D student at Oxford University, who was able to simulate this process in a computer model and confirm its potential significance to mixing dense waters downward. On the large-scale modeling side of SNAP-DRAGON, this project enabled a comparison of models with varying resolution and degrees of interaction with the atmosphere. We found that models are able to simulate the observations and show that the Labrador Sea plays a significant role in circulation changes even though it is not as significant a site for densification of water as previously thought. Finally, this project enabled mentorship of an undergraduate summer student, a Ph.D. student, and several postdocs, contributing to the education and strengthening of our academic workforce.

Last Modified: 11/27/2024
Modified by: Isabela A Le Bras