Atmosphere Ocean Science Colloquium

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Turbulent dynamics of the Arctic Ocean and its interactions with the sea ice

Speaker: Georgy Manucharyan, Caltech

Location: Warren Weaver Hall 1302

Date: Wednesday, November 29, 2017, 3:30 p.m.

Synopsis:

Continuing global warming has led to a dramatic decrease of the Arctic summer sea ice extent and thickness, resulting in weaker and more mobile sea ice. In such conditions, the sea ice can efficiently interact with mesoscale and submesoscale ocean turbulence exchanging heat and momentum. In this talk, I will highlight the crucial ways in which the sea ice affects the large-scale circulation as well as explain its interactions with submesoscale ocean variability in marginal ice zones. I will also discuss the role of non-equilibrium eddy-mean flow interactions, focusing on transient halocline dynamics of the Beaufort Gyre — the dominant anticyclonic circulation in the Arctic which stores a critical amount of surface freshwater suppressing the vertical heat exchange with warm water masses at depth. My results suggest that the reduction in sea ice energizes the upper ocean turbulence and enhances the vertical ocean heat transport, thus accelerating the melt. These feedbacks are entirely missing in climate projection models that continue to misrepresent the nature of mesoscale and submesoscale turbulence under the sea ice.