Pancake Ice in a Wave Field

        From many field observations, it has become well known that pancake ice is ubiquitous in a wave-dominated sea. These strikingly uniform circular floes are consistently found in the Antarctic seas during the ice formation season. Their presence has also been reported in the Bering Sea, the Greenland sea, and in polynyas and leads within pack ice. In one estimate made by Peter Wadhams, the areal coverage of pancake ice in the Southern Ocean MIZ is around 6 million km².

Pancake ice forms through a combination of thermodynamic growth and mechanical thickening, caused by rafting of floes that is driven by wave motion. This complex growth process is much faster than pure thermodynamic growth and hence may be the main factor responsible for ice edge advance in marginal ice zones.

We simulate wave/ice floe dynamics by combining a new three-dimensional discrete element model with wave hydrodynamics. In the simulations we calculate ice drift speed as a function of wave amplitude and ice collisional dynamics.

Click on the picture below for the Powerpoint presentation:

"Simulation of Pancake Ice Dynamics In a Wave Field"

We also simulate ice build-up in front of a non-reflecting vertical barrier. The simulation results show the rate of increase of the ice impact force on the barrier and the rate of thickening of the rafted region in front of the barrier as a function of wave amplitude. Results from this study will help quantify the formation process for pancake ice covers in a wave field.

This work is funded by a grant from the National Science Foundation Office of Polar Programs as part of a project to study the formation of pancake ice with Clarkson University.

Publications:

Frankenstein, S., M.A. Hopkins, and H.H. Shen (2002) Simulation of Pancake Ice Dynamics in a Wave Field, Proceedings of the 16th IAHR Ice Symposium, December 2-6, 2002, Dunedin.

Hopkins, M.A. and H.H. Shen (2001) Simulation of Pancake-Ice Dynamics in a Wave Field. Annals of Glaciology, Vol. 33, 355-360.

Shen, H.H., S.F. Ackley and M.A. Hopkins (2001) A Conceptual Model for Pancake-Ice Formation in a Wave Field. Annals of Glaciology, Vol. 33, 361-367.