The effect of uncertainties in creep activation energies on modeling ice flow and deformation

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Authors

Meghana Ranganathan , Brent Minchew

Abstract

Ice deformation is commonly represented by a power-law constitutive relation, Glen's Flow Law, where deformation (strain) rate equals stress raised to the power n and multiplied by a flow-rate parameter A. Glen's Law represents bulk ice rheology as a single power-law even though multiple mechanisms, each with their own power-law relation and parametric values, act together during viscous deformation (creep) of ice. The relative importance of different creep mechanisms in naturally- deforming ice sheets controls the parameters n and A in Glen's Flow Law. We couple a composite flow law that explicitly represents individual deformation mechanisms with models for ice temperature and grain size to estimate the dominant deformation mechanism in the Antarctic Ice Sheet. We demonstrate that uncertainties in creep activation energies produce significant uncertainties in the dominant deformation mechanism, and thus values of A and n. Minor variations in the activation energy values (<10% or <5 kJ/mol) can change the dominant creep mechanism, causing n to vary between 1.8

DOI

https://doi.org/10.31223/X5V94S

Subjects

Earth Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics

Keywords

glaciers, rheology, ice dynamics, ice sheets, Antarctica, Antarctic Ice Sheet

Dates

Published: 2022-11-21 07:39

Last Updated: 2022-11-21 07:39

License

CC-BY Attribution-NonCommercial 4.0 International

Additional Metadata

Conflict of interest statement:
None

Data Availability (Reason not available):
The source code for the model presented in this study are openly available at https://github.com/megr090/ActivationEnergyUncertainties. No new data were produced for this study, and data used in this study are publicly available through their respective publications.

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