Sack Lunch Seminar (SLS)

Title: “The Ice-Ocean governor: Ice-ocean stress feedback limits Beaufort Gyre spin up.”

Abstract: The Beaufort Gyre is a key circulation system of the Arctic Ocean and the main
reservoir of freshwater within it. Storage and release of its freshwater not only
has significant implications for the fate of Arctic sea ice cover, but also to
climate in the North Atlantic and globally. I will present a mechanism that is
fundamental to the dynamics of the Arctic and its ability to store fresh water,
namely the "ice-ocean governor". Wind blows over the ice and the ice drags
the ocean along with it. But as the gyre spins up, surface currents catch the
ice up and effectively turn off the Ekman pumping. This governor sets the basic
properties of the gyre, such as its depth, freshwater content, and strength.
Analytical and numerical modeling is employed to demonstrate the
mechanism, contrasting equilibration processes in an ice-covered versus icefree
gyre. Observations are presented and interpreted in terms of the governor
mechanism. I will discuss the ice-ocean governor consequences for
freshwater accumulation and release in a warming climate with continued seaice
losses.