the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
The comparative role of physical system processes in Hudson Strait ice stream cycling: a comprehensive model-based test of Heinrich event hypotheses
Abstract. Despite their recognized significance on global climate and extensive research efforts, the mechanism(s) driving Heinrich Events remain(s) a subject of debate. Here, we use the 3D thermo-mechanically coupled Glacial Systems Model (GSM) to examine Hudson Strait ice stream surge cycling as well as the role of 3 factors previously hypothesized to play a critical role in Heinrich events: ice shelves, glacial isostatic adjustment, and sub-surface ocean temperature forcings. In contrast to all previous modeling studies examining HEs, the GSM uses a transient last glacial cycle climate forcing, global visco-elastic glacial isostatic adjustment model, and sub-glacial hydrology model. The results presented here are based on a high-variance sub-ensemble retrieved from North American history matching for the last glacial cycle.
Over our comparatively wide sampling of the potential parameter space (52 ensemble parameters for climate forcing and process uncertainties), we find two modes of Hudson Strait ice streaming: classic binge-purge versus near continuous ice streaming with occasional shutdowns and subsequent surge onset overshoot. Our model results indicate that large ice shelves covering the Labrador Sea during the last glacial cycle only occur when extreme calving restrictions are applied. The otherwise minor ice shelves provide insignificant buttressing for the Hudson Strait ice stream. While sub-surface ocean temperature forcing leads to minor differences regarding surge characteristics, glacial isostatic adjustment does have a significant impact. Given input uncertainties, the strongest controls on ice stream surge cycling are the poorly constrained deep geothermal heat flux under Hudson Bay and Hudson Strait and the basal drag law. Decreasing the geothermal heat flux within available constraints and/or using a Coulomb sliding law instead of a Weertman-type power law leads to a shift from the near-continuous streaming mode to the binge-purge mode.
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Status: closed
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RC1: 'Comment on egusphere-2024-493', Anonymous Referee #1, 06 May 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-493/egusphere-2024-493-RC1-supplement.pdf
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AC1: 'Reply on RC1', Kevin Hank, 20 May 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-493/egusphere-2024-493-AC1-supplement.pdf
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AC1: 'Reply on RC1', Kevin Hank, 20 May 2024
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RC2: 'Review of Hank and Tarasov', Clemens Schannwell, 22 May 2024
Dear Authors,
Please find my review in the attached pdf.Best wishes,
Clemens Schannwell
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AC2: 'Reply on RC2', Kevin Hank, 28 Jun 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-493/egusphere-2024-493-AC2-supplement.pdf
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AC2: 'Reply on RC2', Kevin Hank, 28 Jun 2024
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RC3: 'Comment on egusphere-2024-493', Jorge Alvarez-Solas, 23 May 2024
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AC3: 'Reply on RC3', Kevin Hank, 28 Jun 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-493/egusphere-2024-493-AC3-supplement.pdf
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AC3: 'Reply on RC3', Kevin Hank, 28 Jun 2024
Status: closed
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RC1: 'Comment on egusphere-2024-493', Anonymous Referee #1, 06 May 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-493/egusphere-2024-493-RC1-supplement.pdf
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AC1: 'Reply on RC1', Kevin Hank, 20 May 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-493/egusphere-2024-493-AC1-supplement.pdf
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AC1: 'Reply on RC1', Kevin Hank, 20 May 2024
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RC2: 'Review of Hank and Tarasov', Clemens Schannwell, 22 May 2024
Dear Authors,
Please find my review in the attached pdf.Best wishes,
Clemens Schannwell
-
AC2: 'Reply on RC2', Kevin Hank, 28 Jun 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-493/egusphere-2024-493-AC2-supplement.pdf
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AC2: 'Reply on RC2', Kevin Hank, 28 Jun 2024
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RC3: 'Comment on egusphere-2024-493', Jorge Alvarez-Solas, 23 May 2024
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AC3: 'Reply on RC3', Kevin Hank, 28 Jun 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-493/egusphere-2024-493-AC3-supplement.pdf
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AC3: 'Reply on RC3', Kevin Hank, 28 Jun 2024
Video supplement
Supplementary material for "The comparative role of physical system processes in Hudson Strait ice stream cycling: a comprehensive model-based test of Heinrich event hypotheses" Kevin Hank https://doi.org/10.5281/zenodo.10214928
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