Friday, November 04, 2022 at 10:30am to 11:30am
Narragansett Bay Campus, Corless Auditorium (Watkins Laboratory)
Speaker: Nicholas Foukal, Assistant Scientist, Woods Hole Oceanographic Institution
Title: “On the origins, pathways, and fate of fresh water in the sub-polar North Atlantic”
ABSTRACT: The Atlantic Meridional Overturning Circulation (AMOC) supplies heat and salt to the northern North Atlantic and is a critical component of our climate system. Yet we still lack a satisfactory understanding of the AMOC’s dynamics. Recent progress on this topic has come from the Overturning in the Subpolar North Atlantic Program (OSNAP): despite many previous modeling papers documenting the importance of the Labrador Sea to the AMOC, the Labrador Sea in the OSNAP observations participates very little in the mean AMOC as well as its monthly to inter-annual variability. This lack of variability in the Labrador Sea arises because of density compensation: as the waters circulate cyclonically around the Labrador Sea, they lose heat (becoming denser) and gain fresh water (becoming lighter), so the outflow is a similar density as the inflow. But a key component of this density compensation is the flux of fresh water from high latitudes. If this varies, then variability in the Labrador Sea could indeed become important to the AMOC variability, and in particular at low frequencies. In this talk, I will discuss some recent results on the origins, pathways, and fate of freshwater in the sub-polar North Atlantic, with the goal of understanding how this freshwater flux term will evolve into the future. I will highlight three ongoing observational campaigns that are in different phases of completion: some results from hydrography, numerical models, and OSNAP moorings on the Greenland shelf, some preliminary findings of a targeted Lagrangian experiment around the southern tip of Greenland, and some future plans for moorings on the Labrador Shelf that will be deployed next year on R/V Endeavor.
Free
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