Increasing the Glen–Nye Power‐Law Exponent Accelerates Ice‐Loss Projections for the Amundsen Sea Embayment, West Antarctica

Abstract Glacier flow is typically modeled using a power‐law rheology known as the Glen–Nye flow law, with the power n assumed to be 3. However, recent research and past observations suggest that n=4 may better represent ice flow in some locations. We lack a quantitative understanding of how much n...

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Main Authors: Benjamin Getraer, Mathieu Morlighem
Format: Article
Language:English
Published: Wiley 2025-04-01
Series:Geophysical Research Letters
Online Access:https://doi.org/10.1029/2024GL112516
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author Benjamin Getraer
Mathieu Morlighem
author_facet Benjamin Getraer
Mathieu Morlighem
author_sort Benjamin Getraer
collection DOAJ
description Abstract Glacier flow is typically modeled using a power‐law rheology known as the Glen–Nye flow law, with the power n assumed to be 3. However, recent research and past observations suggest that n=4 may better represent ice flow in some locations. We lack a quantitative understanding of how much n affects ice‐loss projections, and its significance relative to other sources of uncertainty. Here, we test the effect of n=3 versus n=4 in a series of 300‐year forward simulations of the Amundsen Sea Embayment, West Antarctica. We find that in periods of rapid grounding line retreat, uncertainty in n leads to a larger spread in ice‐loss projections than the spread due to uncertainty in climate forcing. The spatial sensitivity of n is generally proportional to change in strain rates, so we expect regions undergoing more moderate dynamic change to be less sensitive to n.
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spelling doaj-art-aaeea5bbd034439c82a44acb3876dc092025-08-20T02:30:59ZengWileyGeophysical Research Letters0094-82761944-80072025-04-01527n/an/a10.1029/2024GL112516Increasing the Glen–Nye Power‐Law Exponent Accelerates Ice‐Loss Projections for the Amundsen Sea Embayment, West AntarcticaBenjamin Getraer0Mathieu Morlighem1Department of Earth Sciences Dartmouth College Hanover NH USADepartment of Earth Sciences Dartmouth College Hanover NH USAAbstract Glacier flow is typically modeled using a power‐law rheology known as the Glen–Nye flow law, with the power n assumed to be 3. However, recent research and past observations suggest that n=4 may better represent ice flow in some locations. We lack a quantitative understanding of how much n affects ice‐loss projections, and its significance relative to other sources of uncertainty. Here, we test the effect of n=3 versus n=4 in a series of 300‐year forward simulations of the Amundsen Sea Embayment, West Antarctica. We find that in periods of rapid grounding line retreat, uncertainty in n leads to a larger spread in ice‐loss projections than the spread due to uncertainty in climate forcing. The spatial sensitivity of n is generally proportional to change in strain rates, so we expect regions undergoing more moderate dynamic change to be less sensitive to n.https://doi.org/10.1029/2024GL112516
spellingShingle Benjamin Getraer
Mathieu Morlighem
Increasing the Glen–Nye Power‐Law Exponent Accelerates Ice‐Loss Projections for the Amundsen Sea Embayment, West Antarctica
Geophysical Research Letters
title Increasing the Glen–Nye Power‐Law Exponent Accelerates Ice‐Loss Projections for the Amundsen Sea Embayment, West Antarctica
title_full Increasing the Glen–Nye Power‐Law Exponent Accelerates Ice‐Loss Projections for the Amundsen Sea Embayment, West Antarctica
title_fullStr Increasing the Glen–Nye Power‐Law Exponent Accelerates Ice‐Loss Projections for the Amundsen Sea Embayment, West Antarctica
title_full_unstemmed Increasing the Glen–Nye Power‐Law Exponent Accelerates Ice‐Loss Projections for the Amundsen Sea Embayment, West Antarctica
title_short Increasing the Glen–Nye Power‐Law Exponent Accelerates Ice‐Loss Projections for the Amundsen Sea Embayment, West Antarctica
title_sort increasing the glen nye power law exponent accelerates ice loss projections for the amundsen sea embayment west antarctica
url https://doi.org/10.1029/2024GL112516
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