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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:	Refereed Article
Keywords:	pancake ice, Antarctic Marginal Ice Zone, wave-ice interaction, buoy
Research Division:	Earth Sciences
Research Group:	Other Earth Sciences
Research Field:	Earth Sciences not elsewhere classified
Objective Division:	Environment
Objective Group:	Climate and Climate Change
Objective Field:	Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts)
UTAS Author:	Heil, P (Dr Petra Heil)
ID Code:	139717
Year Published:	2020
Deposited By:	Australian Antarctic Program Partnership
Deposited On:	2020-06-29
Last Modified:	2020-06-30
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