Oct 17, 2018

The Ice‐Ocean governor: ice‐ocean stress feedback limits Beaufort Gyre spin up

by
Gianluca Meneghello, John Marshall, Jean‐Michel Campin, Edward Doddridge, Mary‐Louise Timmermans
,
Geophysical Research Letters
  • States that:
    • The Beaufort Gyre, located north of Alaska and Canada, is a key circulation system of the Arctic Ocean
    • Changes in its depth and circulation influence the evolution of the Arctic sea ice cover, the North Atlantic circulation and the global climate
  • Describes the "ice‐ocean governor" mechanism, in which the interaction of surface currents with the ice regulates the depth of the Beaufort Gyre: the spinning up of the gyre reduces the relative speed between the ocean and the ice, and hence the fresh water accumulation
  • Notes that in a warming world, reduced ice cover may render the ice‐ocean governor less effective
  • Employs analytical and numerical modeling to contrast the equilibration processes in an ice‐covered versus ice‐free gyre
  • Argues 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