BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Elizabeth Yankovsky (New York University) DTSTART:20210519T130000Z DTEND:20210519T140000Z DTSTAMP:20260423T021416Z UID:BAS-PO/17 DESCRIPTION:Title: Constraining water mass transformation and overflow dynamics on the Arctic shelves\nby Elizabeth Yankovsky (New York University) as part of BAS Polar Oceans Seminar\n\n\nAbstract\nDense gravity currents forced by surfa ce buoyancy loss over polar continental shelves are important contributors to subsurface and abyssal ventilation throughout the World Ocean\, yet re main challenging to observe and represent accurately in models. The vast\, and rapidly evolving Arctic shelves are particularly crucial in setting w ater mass structure of the entire basin and influencing its response to ch anging climatic conditions. Observations indicate that some of the stronge st water mass transformation processes in the Arctic occur in the Barents and Kara Sea shelves. The combination of cooling of warm Atlantic inflow a s well as localized polynya development around Svalbard\, Franz Josef Land \, and Novaya Zemlya leads to development of waters with higher densities than even the deepest layers of the Arctic. Depending on the amount of mix ing and strength of the buoyancy forcing\, these dense overflows may also ventilate the Arctic halocline layer.\n\n \n\nIn the first part of the tal k\, I will present idealized high-resolution simulations aimed at studying the dynamics of rotating dense overflows. I will discuss the role of meso scale baroclinic eddies and submesoscale symmetric instability in setting the pathways and properties of the dense waters. In the second part\, we w ill examine how modern state-of-the-art general circulation models present ly capture shelf overflow dynamics in the Arctic. We consider: (1) whether dense shelf overflows and the vertical structure of the Arctic are well-r epresented by the GFDL-OM4 1/4-degree model as well as an analogous 1/8-de gree version\; and (2) pathways by which overflows and water mass transfor mation over the Eurasian shelves contribute to setting the vertical struct ure of the interior Arctic. We also explore the changes in ventilation pat hways that the Arctic will experience as a result of warming. In particula r – we see evidence for dense water formation changing from being influe nced by polynyas and brine rejection as sea ice forms to being predominant ly set by cooling of the inflowing\, highly saline Atlantic waters.\n LOCATION:https://researchseminars.org/talk/BAS-PO/17/ END:VEVENT END:VCALENDAR