Atmosphere Ocean Science Colloquium

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The Ice-Ocean Governor: ice-ocean stress feedback limits Beaufort Gyre spin up

Speaker: Gianluca Meneghello, MIT

Location: Warren Weaver Hall 1302

Date: Wednesday, April 17, 2019, 3:30 p.m.

Synopsis:

The Beaufort Gyre is a key circulation system of the Arctic Ocean and its main reservoir of freshwater. Freshwater storage and release affects Arctic sea ice cover, as well as North Atlantic and global climate. 

We will talk about a mechanism that is fundamental to the dynamics of the gyre: the ice-ocean stress governor. Wind blows over the ice, and the ice drags the ocean. But as the gyre spins up, currents catch the ice up and turn off the surface stress. This governor sets the basic properties of the gyre, such as its depth, freshwater content, and strength.  

We will look at the ice-ocean governor from the theoretical, numerical and the observational point of view. I will then argue that as the Arctic warms, reduced sea ice extent and more mobile ice will result in a deeper and faster Beaufort Gyre, accumulating more freshwater that will be released by Ekman upwelling or baroclinic instability.