Towards a process model for predicting potential anchor ice formation sites in coastal Antarctic waters

Abstract

Anchor ice describes clusters of ice attached to the beds of rivers, lakes or seas. In Antarctica, ice shelves are considered to be a main driver of anchor ice formation through a process commonly referred to as an ‘ice pump’. These pumps melt the base of an ice shelf at depth and produce a buoyancy-driven plume of meltwater that rises along the basal plane, becoming potentially supercooled in the process. Anchor ice growth may be initiated in regions where plumes intersect the local seafloor. A simple process model is proposed to predict these growth sites in coastal Antarctic waters. A comparison with model output and anchor ice observations in McMurdo Sound reveals that model-predicted formation sites are consistent with these observations. Knowledge of ice shelf draft, basal slope and cavity circulation is necessary to extend the model beyond the confines of McMurdo Sound.

Keywords::

• anchor ice
• Antarctica
• ice shelf
• coastal bathymetry
• McMurdo Sound
• supercooled water

Acknowledgements

Andrew Pauling’s participation in this study was funded by a University of Otago Polar Environments Research Theme Summer Bursary (2012 – 2013). The authors would like to thank the two anonymous reviewers for their comments and suggestions.