The Impact of Basal Roughness on Inland Thwaites Glacier Sliding

Hoffman, Andrew O.; Christianson, Knut; Holschuh, Nicholas; Case, Elizabeth; Kingslake, Jonathan; Arthern, Robert

doi:10.1029/2021gl096564

Cited by 6 publications

(3 citation statements)

References 43 publications

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“…Recent work has also improved the characterization of the material and morphology of ice-sheet beds. Detailed analysis of wide-band and swath-imaging radar systems have revealed fine scale morphology of features on the bed which impacts basal sliding and ice flow others, 2021, 2022;Hoffman and others, 2022). As have dense ground-based surveys (Schlegel and others, 2022).…”

Section: Recent Progress In Data Analysismentioning

confidence: 98%

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Paths forward in radioglaciology

Schroeder

2022

Ann. Glaciol.

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Ice-penetrating radar sounding is a powerful geophysical tool for studying terrestrial and planetary ice with a rich glaciological heritage reaching back over half a century. Recent years have also seen rapid growth in both the radioglaciological community itself and in the scope and sophistication of its analysis of ice-penetrating radar data. This has been spurred by a combination of growing datasets and improvements in computational resources as well as advances in radar sounding instrumentation and platforms. Together, these developments are transforming the field and highlight exciting paths forward for future innovation and investigation.

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Section: Recent Progress In Data Analysismentioning

confidence: 98%

“…Repeat-pass radar sounding also has the potential to dramatically improve bed topography with swath imaging (e.g. Hoffman and others, 2022). This surveydependent data richness is particularly well suited to the adaptive and target-specific surveying capacity of UAVs and for feeding data-rich empirical approaches (e.g.…”

Section: Future Directions In Technologymentioning

confidence: 99%

Paths forward in radioglaciology

Schroeder

2022

Ann. Glaciol.

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“…The 'law' must represent ice motion over a wide range of topographic features and a mosaic of bed types involving both till and bedrock. Many of these features are large enough to be resolved in geophysical surveys and models, but smaller features require parameterizations (Hoffman and others, 2022). We will refer to sliding laws here for simplicity.…”

Section: Basal 'Sliding Law'mentioning

confidence: 99%

GHOSTly flute music: drumlins, moats and the bed of Thwaites Glacier

Alley,

Holschuh,

Parizek

et al. 2022

Ann. Glaciol.

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Glacier-bed characteristics that are poorly known and modeled are important in projected sea-level rise from ice-sheet changes under strong warming, especially in the Thwaites Glacier drainage of West Antarctica. Ocean warming may induce ice-shelf thinning or loss, or thinning of ice in estuarine zones, reducing backstress on grounded ice. Models indicate that, in response, more-nearly-plastic beds favor faster ice loss by causing larger flow acceleration, but more-nearly-viscous beds favor localized near-coastal thinning that could speed grounding-zone retreat into interior basins where marine-ice-sheet instability or cliff instability could develop and cause very rapid ice loss. Interpretation of available data indicates that the bed is spatially mosaicked, with both viscous and plastic regions. Flow against bedrock topography removes plastic lubricating tills, exposing bedrock that is eroded on up-glacier sides of obstacles to form moats with exposed bedrock tails extending downglacier adjacent to lee-side soft-till bedforms. Flow against topography also generates high-ice-pressure zones that prevent inflow of lubricating water over distances that scale with the obstacle size. Extending existing observations to sufficiently large regions, and developing models assimilating such data at the appropriate scale, present large, important research challenges that must be met to reliably project future forced sea-level rise.

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Exploring canyons beneath Devon Ice Cap for sub-glacial drainage using radar and thermodynamic modeling

Pierce,

Skidmore,

Beem

et al. 2024

J. Glaciol.

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Sub-glacial canyon features up to 580 m deep between flat terraces were identified beneath Devon Ice Cap during a 2023 radar echo sounding (RES) survey. The largest canyon connects a hypothesized brine network near the Devon Ice Cap summit with the marine-terminating Sverdrup outlet glacier. This canyon represents a probable drainage route for the hypothesized water system. Radar bed reflectivity is consistently 30 dB lower along the canyon floor than on the terraces, contradicting the signature expected for sub-glacial water. We compare these data with backscattering simulations to demonstrate that the reflectivity pattern may be topographically induced. Our simulated results indicated a 10 m wide canal-like water feature is unlikely along the canyon floor, but smaller features may be difficult to detect via RES. We calculated basal temperature profiles using a 2D finite difference method and found the floor may be up to 18°C warmer than the terraces. However, temperatures remain below the pressure melting point, and there is limited evidence that the canyon floor supports a connected drainage system between the DIC summit and Sverdrup Glacier. The terrain beneath Devon Ice Cap demonstrates limitations for RES. Future studies should evaluate additional correction methods near complex terrain, such as RES simulation as we demonstrate here.

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The Impact of Basal Roughness on Inland Thwaites Glacier Sliding

Cited by 6 publications

References 43 publications

Paths forward in radioglaciology

Paths forward in radioglaciology

GHOSTly flute music: drumlins, moats and the bed of Thwaites Glacier

Exploring canyons beneath Devon Ice Cap for sub-glacial drainage using radar and thermodynamic modeling

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