Diverse landscapes beneath Pine Island Glacier influence ice flow

Bingham, Robert G.; Vaughan, David G.; King, Edward C.; Davies, Damon; Cornford, Stephen; Smith, Andrew M.; Arthern, Robert; Brisbourne, Alex; Rydt, Jan De; Graham, Alastair G C; Spagnolo, Matteo; Marsh, Oliver J.; Shean, David

doi:10.1038/s41467-017-01597-y

Cited by 59 publications

(77 citation statements)

References 54 publications

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“…Increased bed roughness is also reflected in rougher ice surface (Figures c and S2f). A rough bed has also been observed at Pine Island Glacier, where seismic data showed that crystalline bedrock is overlain by up to 10 m of sediments (Bingham et al, ; Brisbourne et al, ). However, such information cannot be derived from our radar data alone.…”

Section: Discussionmentioning

confidence: 92%

Basal Settings Control Fast Ice Flow in the Recovery/Slessor/Bailey Region, East Antarctica

Diez

Matsuoka

Ferraccioli

et al. 2018

Geophysical Research Letters

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The region of Recovery Glacier, Slessor Glacier, and Bailey Ice Stream, East Antarctica, has remained poorly explored, despite representing the largest potential contributor to future global sea level rise on a centennial to millennial time scale. Here we use new airborne radar data to improve knowledge about the bed topography and investigate controls of fast ice flow. Recovery Glacier is underlain by an 800 km long trough. Its fast flow is controlled by subglacial water in its upstream and topography in its downstream region. Fast flow of Slessor Glacier is controlled by the presence of subglacial water on a rough crystalline bed. Past ice flow of adjacent Recovery and Slessor Glaciers was likely connected via the newly discovered Recovery‐Slessor Gate. Changes in direction and speed of past fast flow likely occurred for upstream parts of Recovery Glacier and between Slessor Glacier and Bailey Ice Stream. Similar changes could also reoccur here in the future.

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Section: Discussionmentioning

confidence: 92%

Basal Settings Control Fast Ice Flow in the Recovery/Slessor/Bailey Region, East Antarctica

Diez

Matsuoka

Ferraccioli

et al. 2018

Geophysical Research Letters

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“…This resulted in the first subkilometer‐scale basal topography data set across tributaries of PIG. Further details about the data sets and their acquisition can be found in Bingham et al (). For reference, Figure shows these bed elevation data, alongside the surface elevation and surface velocity data (Landsat8 velocities, Fahnestock et al, ) for five of these areas.…”

Section: Data and Modelmentioning

confidence: 99%

Can Seismic Observations of Bed Conditions on Ice Streams Help Constrain Parameters in Ice Flow Models?

2017

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We investigate correlations between seismically derived estimates of basal acoustic impedance and basal slipperiness values obtained from a surface‐to‐bed inversion using a Stokes ice flow model. Using high‐resolution measurements along several seismic profiles on Pine Island Glacier (PIG), we find no significant correlation at kilometer scale between acoustic impedance and either retrieved basal slipperiness or basal drag. However, there is a stronger correlation when comparing average values along the individual profiles. We hypothesize that the correlation appears at the length scales over which basal variations are important to large‐scale ice sheet flow. Although the seismic technique is sensitive to the material properties of the bed, at present there is no clear way of incorporating high‐resolution seismic measurements of bed properties on ice streams into ice flow models. We conclude that more theoretical work needs to be done before constraints on mechanical conditions at the ice‐bed interface from acoustic impedance measurements can be of direct use to ice sheet models.

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“…The main trunk of PIG is fed by seven tributaries (T1–T7, Figure ) underlain by contrasting topographic (Bingham et al, ; Vaughan et al, ), frictional (Gillet‐Chaulet et al, ; Joughin et al, ), and geological properties (Brisbourne et al, ; Smith et al, ). The surface slopes of its northern tributaries (T4 and T6) are low, and the basal topography is relatively smooth (Figure ).…”

Section: Introductionmentioning

confidence: 99%

Contrasting Hydrological Controls on Bed Properties During the Acceleration of Pine Island Glacier, West Antarctica

et al. 2019

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In the Amundsen sector of West Antarctica, the flow of glaciers accelerates when intrusion of warm ocean water onto the continental shelf induces strong melting beneath ice shelves and thinning near the glaciers' grounding line. Predicting the future of these glaciers is, however, hindered by a poor understanding of the dynamical processes that may exacerbate, or on the contrary modulate, the inland ice sheet response. This study seeks to investigate processes occurring at the base of Pine Island Glacier through numerical inversions of surface velocities observed in 1996 and 2014, a period of time during which the glacier accelerated significantly. The outputs show that substantial changes took place in the basal environment, which we interpret with models of undrained subglacial till and hydrological routing. The annual basal melt production increased by 25% on average. Basal drag weakened by 15% over nearly two thirds of the region of accelerated flow, largely due to the direct assimilation of locally produced basal meltwater into the underlying subglacial sediment. In contrast, regions of increased drag are found to follow several of the glacier's shear margins and furthermore to coincide with inferred hydrological pathways. We interpret this basal strengthening as signature of an efficient hydrological system, where low-pressure water channels have reduced the surrounding basal water pressure. These are the first identified stabilization mechanisms to have developed alongside Pine Island ice flow acceleration. Indeed, these processes could become more significant with increased meltwater availability and may limit the glacier's response to perturbation near its grounding line.

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Diverse landscapes beneath Pine Island Glacier influence ice flow

Cited by 59 publications

References 54 publications

Basal Settings Control Fast Ice Flow in the Recovery/Slessor/Bailey Region, East Antarctica

Basal Settings Control Fast Ice Flow in the Recovery/Slessor/Bailey Region, East Antarctica

Can Seismic Observations of Bed Conditions on Ice Streams Help Constrain Parameters in Ice Flow Models?

Contrasting Hydrological Controls on Bed Properties During the Acceleration of Pine Island Glacier, West Antarctica

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