A unifying framework for iceberg-calving models

• Published in: Journal of Glaciology
• Main Authors: Amundson, Jason M., Truffer, Martin
• Format: Article in Journal/Newspaper
• Language: English
• Published: International Glaciological Society 2010
• Subjects: glaciers; iceberg calving; icebergs; calving; calving framework; terminus velocity; glacier flow; terminus thickness; Arctic; Cooperative Institute for Arctic Research; Ice Shelf; Iceberg*; International Polar Year; Journal of Glaciology
• Online Access: http://hdl.handle.net/11122/11045

We propose a general framework for iceberg-calving models that can be applied to any calving margin. We propose a general framework for iceberg-calving models that can be applied to any calving margin. The framework is based on mass continuity, the assumption that calving rate and terminus velocity are not independent and the simple idea that terminus thickness following a calving event is larger than terminus thickness at the event onset. The theoretical, near steady-state analysis used to support and analyze the framework indicates that calving rate is governed, to first order, by ice thickness, thickness gradient, strain rate, mass-balance rate and backwards melting of the terminus; the analysis furthermore provides a physical explanation for a previously derived empirical relationship for ice-shelf calving (Alley and others, 2008). In the calving framework the pre- and post-calving terminus thicknesses are given by two unknown but related functions. The functions can vary independently of changes in glacier flow and geometry, and can therefore account for variations in calving behavior due to external forcings and/or self-sustaining calving processes (positive feedbacks). Although the calving framework does not constitute a complete calving model, any thickness-based calving criterion can easily be incorporated into the framework. The framework should be viewed as a guide for future attempts to parameterize calving. Support for this project was provided by NASA’s Cryospheric Sciences Program (NNG06GB49G), the US National Science Foundation (ARC0531075 and ARC0909552) and an International Polar Year student traineeship funded by the Cooperative Institute for Arctic Research (CIFAR) through cooperative agreement NA17RJ1224 with the US National Oceanic and Atmospheric Administration. The paper was inspired by discussions with E. Bueler, M. Fahnestock, M.P. Lu ̈thi, R.J. Motyka, J. Brown and D. Podrasky. We thank A. Vieli, an anonymous reviewer and the scientific editor, R. Greve, for thorough reviews that ...