A computational investigation of iceberg capsize as a driver of explosive ice-shelf disintegration.

• Main Authors: Amundson, Jason M., Guttenberg, Nicolas, Abbott, Dorian S., Burton, Justin C., Cathles, L. M., Macayeal, Douglas R., Zhang, Wendy W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: International Glaciology Society 2011
• Subjects: Ice-shelf disintegration; Ice-shelf collapse; ice-shelf fragment capsize; iceberg capsize; Antarctic; Antarctic Peninsula; Stearns; The Antarctic; Wilkins; Annals of Glaciology; Antarc*; Ice Shelf; Ice Shelves; Iceberg*
• Online Access: http://hdl.handle.net/11122/11310

Potential energy released from the capsize of ice-shelf fragments (icebergs) is the immediate driver of the brief explosive phase of ice-shelf disintegration along the Antarctic Peninsula (e.g. the Larsen A, Larsen B and Wilkins ice shelves). The majority of this energy powers the rapidly expanding plume of ice-shelf fragments that expands outward into the open ocean; a smaller fraction of this energy goes into surface gravity waves and other dynamic interactions between ice and water that can sustain the continued fragmentation and break-up of the original ice shelf. As an initial approach to the investigation of ice-shelf fragment capsize in ice-shelf collapse, we develop a simple conceptual model involving ideal rectangular icebergs, initially in unstable or metastable orientations, which are assembled into a tightly packed mass that subsequently disassembles via massed capsize. Computations based on this conceptual model display phenomenological similarity to aspects of real ice-shelf collapse. A promising result of the conceptual model presented here is a description of how iceberg aspect ratio and its statistical variance, the two parameters related to ice-shelf fracture patterns, influence the enabling conditions to be satisfied by slow-acting processes (e.g. environmentally driven melting) that facilitate ice-shelf disintegration. This work is supported by the US National Science Foundation under grants ANT-0944193, OPP-0838811 and CMG-0934534. D.S. Abbot was supported by the T.C. Chamberlin Fellowship of the University of Chicago and the Canadian Institute for Advanced Research. We thank reviewers J. Johnson and T. Scambos and scientific editor L. Stearns for substantial help in clarifying the work presented here. The first author innovated the methods and performed the computations presented here. Co-authors, listed in alphabetical order, had significant but supportive roles. Yes