Sea-Ice Distribution and Mixed-Layer Depths in Fram Strait

Sahil Agarwal; M. Grae Worster

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arXiv · 1712.07599

Sea-Ice Distribution and Mixed-Layer Depths in Fram Strait

Sahil Agarwal·M. Grae Worster

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Abstract

In an effort to understand the dynamics of the Arctic sea-ice edge, we present a simple model of heat and mass transfer in the Fram Strait that reveals some fundamental mechanisms controlling sea-ice extent in the marginal seas and the depth and properties of the Arctic mixed layer. We identify and study key mechanisms relating to the sea-ice wedge described by Untersteiner, a boundary-layer structure near the ice edge, demonstrating how ice thickness and extent depend on ice-export rates, atmospheric forcing and the properties of incoming warm and salty Atlantic water in the West Spitsbergen Current. Our time-dependent results demonstrate a seasonal asymmetry between the rates of ice advance and retreat and explain the significant variations in the Southerly extent of sea ice across the Fram Strait, with a long ice tongue corresponding with the East Greenland Current. Our simple model indicates that thinning of the Arctic sea-ice cover will lead to warming and freshening of the North Atlantic, which would give a de-stabilizing feedback to the Arctic ice cover, leading to a slowdown of the Atlantic Meridional Overturning Circulation.

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Sahil Agarwal, M. Grae Worster. 2017-12-20. Sea-Ice Distribution and Mixed-Layer Depths in Fram Strait. https://arxiv.org/abs/1712.07599

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