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Abstract Totten Glacier is a fast‐moving East Antarctic outlet with the potential for significant future sea‐level contributions. We deployed four autonomous phase‐sensitive radars on its ice shelf to monitor ice‐ocean interactions near its grounding zone and made active source seismic observations to constrain gravity‐derived bathymetry models. We observe an asymmetry in basal melting with mean melt rates along the grounding zone differing by up to 20 m/a. Our new bathymetry model reveals that this melt rate asymmetry coincides with an asymmetry in water column thickness and that the low‐melting ice‐shelf portion is shielded from the main cavity circulation. A 2‐year record yields year‐to‐year melt rate variability of 7–9 m/a with no seasonal cycle. Our results highlight the key role of bathymetry near grounding lines for accurate modeling of ice‐shelf melt, and the importance of sustained multi‐year monitoring, especially at ice‐shelf cavities where the dominant melt rate drivers vary primarily inter‐annually.
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This content will become publicly available on May 16, 2026
Novel Record of Intermittent Grounding of the Venable Ice Shelf Since 1935 From Operation IceBridge Airborne‐Gravity‐Derived Bathymetry and Landsat Imagery
Abstract Future projections and past reconstructions of Antarctic Ice Sheet stability and sea‐level rise depend on knowledge of continental shelf bathymetry, which controls water circulation under floating ice and interactions between the ice shelf and seafloor. We present a bathymetry model of the Venable Ice Shelf (VIS) in the Bellingshausen Sea sector from an inversion of airborne gravity data. The new model reveals troughs up to ∼1.6 km deeper than previously mapped, providing pathways for warm Circumpolar Deep Water to access the grounding line. A bathymetric high beneath the western VIS is identified as a former pinning point. From crevasse patterns in Landsat satellite imagery, we infer intermittent grounding of the ice shelf on this high since ∼1935, and we interpret these patterns as evidence of mid‐20th century ice‐shelf thinning, in addition to a regrounding between 1970 and 1988, extending the ice‐shelf thickness record beyond the satellite era.
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- Award ID(s):
- 2002346
- PAR ID:
- 10621910
- Publisher / Repository:
- American Geophysical Union
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 52
- Issue:
- 9
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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