Wave erosion, frontal bending, and calving at Ross Ice Shelf
<p>Ice shelf calving constitutes roughly half of the total mass loss from the Antarctic ice sheet. Although much attention is paid to calving of giant tabular icebergs, these events are relatively rare. Here, we investigate the role of frontal melting and stresses at the ice shelf front in dri...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2025-01-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/19/249/2025/tc-19-249-2025.pdf |
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| Summary: | <p>Ice shelf calving constitutes roughly half of the total mass loss from the Antarctic ice sheet. Although much attention is paid to calving of giant tabular icebergs, these events are relatively rare. Here, we investigate the role of frontal melting and stresses at the ice shelf front in driving bending and calving on the scale of <span class="inline-formula">∼100</span> m, perpendicular to the ice edge. We focus in particular on how buoyant underwater “feet” that protrude beyond the above-water ice cliff may cause tensile stresses at the base of the ice. Indirect and anecdotal observations of such feet at the Ross Ice Shelf front suggest that the resulting bending may be widespread and can trigger calving. We consider satellite observations together with an elastic beam model and a parameterization of wave erosion to better understand the dynamics at the ice shelf front. Our results suggest that on average frontal ablation rather consistently accounts for <span class="inline-formula">20±5</span> m yr<span class="inline-formula"><sup>−1</sup></span> of ice loss at Ross Ice Shelf, likely mostly due to wave erosion and smaller-scale, <span class="inline-formula">𝒪</span>(100 m), foot-induced calving. This constitutes only <span class="inline-formula">∼2</span> % of the total frontal mass loss (since near-front ice velocities are <span class="inline-formula">∼1000</span> m yr<span class="inline-formula"><sup>−1</sup></span>). Observational evidence suggests that sporadic larger events can skew this rate (we document one foot-induced calving event of size <span class="inline-formula">∼1</span> km). Stresses from foot-induced bending are likely not sufficient to initiate crevassing but rather act to propagate existing crevasses. In addition, our results support recent findings by <span class="cit" id="xref_text.1"><a href="#bib1.bibx12">Buck</a> (<a href="#bib1.bibx12">2024</a>)</span> that additional bending moments, likely due to temperature gradients in the ice, may play a role in driving frontal deflections. The highly variable environment, irregularity of pre-existing crevasse spacing, and complex rheology of the ice continue to pose challenges in better constraining the drivers behind the observed deformations and resulting calving rates.</p> |
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| ISSN: | 1994-0416 1994-0424 |