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Drift of pancake ice floes in the winter Antarctic Marginal Ice Zone during polar cyclones

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Alberello, A, Bennetts, L, Heil, P, Eayrs, C, Vichi, M, MacHutchon, K, Onorato, M and Toffoli, A 2020 , 'Drift of pancake ice floes in the winter Antarctic Marginal Ice Zone during polar cyclones' , JGR Oceans, vol. 125, no. 3 , pp. 1-16 , doi: 10.1029/2019JC015418.

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Abstract

High temporal resolution in situ measurements of pancake ice drift are presented, from a pair of buoys deployed on floes in the Antarctic marginal ice zone during the winter sea ice expansion, over 9 days in which the region was impacted by four polar cyclones. Concomitant measurements of wave‐in‐ice activity from the buoys are used to infer that the ice remained unconsolidated, and pancake ice conditions were maintained over at least the first 7 days. Analysis of the data shows (i) the fastest reported ice drift speeds in the Southern Ocean; (ii) high correlation of drift velocities with the surface wind velocities, indicating absence of internal ice stresses >100 km from the ice edge where remotely sensed ice concentration is 100%; and (iii) presence of a strong inertial signature with a 13 hr period. A Lagrangian free drift model is developed, including a term for geostrophic currents that reproduce the 13 hr period signature in the ice motion. The calibrated model provides accurate predictions of the ice drift for up to 2 days, and the calibrated parameters provide estimates of wind and ocean drag for pancake floes under storm conditions.

Item Type: Article
Authors/Creators:Alberello, A and Bennetts, L and Heil, P and Eayrs, C and Vichi, M and MacHutchon, K and Onorato, M and Toffoli, A
Keywords: pancake ice, Antarctic Marginal Ice Zone, wave-ice interaction, buoy
Journal or Publication Title: JGR Oceans
Publisher: Wiley-Blackwell Publishing Inc.
ISSN: 2169-9275
DOI / ID Number: 10.1029/2019JC015418
Copyright Information:

Copyright 2020 American Geophysical Union

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