scholarly journals A Numerical Model Investigation of the Role of the Glacier Bed in Regulating Grounding Line Retreat of Thwaites Glacier, West Antarctica

2017 ◽  
Author(s):  
Michael Waibel
Keyword(s):  
Numerical Model ◽  
Model Investigation ◽  
West Antarctica ◽  
Grounding Line

scholarly journals A Preliminary Model of Holocene Retreat and Thinning of Ice Stream E, West Antarctica (Abstract only)

1982 ◽  
Vol 3 ◽  
pp. 340 ◽  
Author(s):  
Craig S. Lingle ◽  
Charles R. Bentley
Keyword(s):  
Numerical Model ◽  
Continental Shelf ◽  
Sea Level ◽  
Ross Sea ◽  
Two Dimensions ◽  
West Antarctica ◽  
Time Intervals ◽  
Ice Stream ◽  
Preliminary Model ◽  
Grounding Line

A preliminary numerical model of ice-stream grounding-line retreat and thinning as a function of eustatic sea-level rise has been developed. Grounding-line retreat is computed using the methods of Thomas and Bentley (1978). The change in thickness along the ice-stream profile is found by solving the equation of continuity in two dimensions during the time intervals corresponding to increments of grounding-line retreat. The model was applied to ice stream E, West Antarctica, assuming that the ice stream was initially grounded to the edge of the Ross Sea continental shelf.

scholarly journals Sensitivity of the ice-shelf/ocean system to the sub-ice-shelf cavity shape measured by NASA IceBridge in Pine Island Glacier, West Antarctica

2012 ◽  
Vol 53 (60) ◽  
pp. 156-162 ◽  
Author(s):  
Michael P. Schodlok ◽  
Dimitris Menemenlis ◽  
Eric Rignot ◽  
Michael Studinger
Keyword(s):  
Mass Loss ◽  
Temporal Evolution ◽  
West Antarctica ◽  
Ice Shelf ◽  
Amundsen Sea ◽  
Ice Shelves ◽  
Cavity Shape ◽  
Grounding Line ◽  
The Mean

AbstractTwo high-resolution (1 km grid) numerical model simulations of the Amundsen Sea, West Antarctica, are used to study the role of the ocean in the mass loss and grounding line retreat of Pine Island Glacier. The first simulation uses BEDMAP bathymetry under the Pine Island ice shelf, and the second simulation uses NASA IceBridge-derived bathymetry. The IceBridge data reveal the existence of a trough from the ice-shelf edge to the grounding line, enabling warm Circumpolar Deep Water to penetrate to the grounding line, leading to higher melt rates than previously estimated. The mean melt rate for the simulation with NASA IceBridge data is 28 ma–1, much higher than previous model estimates but closer to estimates from remote sensing. Although the mean melt rate is 25% higher than in the simulation with BEDMAP bathymetry, the temporal evolution remains unchanged between the two simulations. This indicates that temporal variability of melting is mostly driven by processes outside the cavity. Spatial melt rate patterns of BEDMAP and IceBridge simulations differ significantly, with the latter in closer agreement with satellite-derived melt rate estimates of ~50ma–1 near the grounding line. Our simulations confirm that knowledge of the cavity shape and its time evolution are essential to accurately capture basal mass loss of Antarctic ice shelves.

scholarly journals A Preliminary Model of Holocene Retreat and Thinning of Ice Stream E, West Antarctica (Abstract only)

1982 ◽  
Vol 3 ◽  
pp. 340-340
Author(s):  
Craig S. Lingle ◽  
Charles R. Bentley
Keyword(s):  
Numerical Model ◽  
Continental Shelf ◽  
Sea Level ◽  
Ross Sea ◽  
Two Dimensions ◽  
West Antarctica ◽  
Time Intervals ◽  
Ice Stream ◽  
Preliminary Model ◽  
Grounding Line

A preliminary numerical model of ice-stream grounding-line retreat and thinning as a function of eustatic sea-level rise has been developed. Grounding-line retreat is computed using the methods of Thomas and Bentley (1978). The change in thickness along the ice-stream profile is found by solving the equation of continuity in two dimensions during the time intervals corresponding to increments of grounding-line retreat. The model was applied to ice stream E, West Antarctica, assuming that the ice stream was initially grounded to the edge of the Ross Sea continental shelf.

ROLE OF GROUNDING ZONE WEDGES IN GROUNDING LINE STABILIZATION: CASE STUDY FROM ROSS SEA

2017 ◽  
Author(s):  
John B. Anderson ◽  
◽  
Lauren Simkins ◽  
Sarah Greenwood ◽  
Brian Demet ◽  
...  
Keyword(s):  
Ross Sea ◽  
Grounding Line

scholarly journals Mass balance of the Antarctic ice sheet 1992–2016: reconciling results from GRACE gravimetry with ICESat, ERS1/2 and Envisat altimetry

2021 ◽  
pp. 1-27
Author(s):  
H. Jay Zwally ◽  
John W. Robbins ◽  
Scott B. Luthcke ◽  
Bryant D. Loomis ◽  
Frédérique Rémy
Keyword(s):  
Mass Balance ◽  
Antarctic Peninsula ◽  
East Antarctica ◽  
Mantle Material ◽  
West Antarctica ◽  
Mantle Viscosity ◽  
Grounding Line ◽  
The Antarctic ◽  
Total Gain

Abstract GRACE and ICESat Antarctic mass-balance differences are resolved utilizing their dependencies on corrections for changes in mass and volume of the same underlying mantle material forced by ice-loading changes. Modeled gravimetry corrections are 5.22 times altimetry corrections over East Antarctica (EA) and 4.51 times over West Antarctica (WA), with inferred mantle densities 4.75 and 4.11 g cm−3. Derived sensitivities (Sg, Sa) to bedrock motion enable calculation of motion (δB0) needed to equalize GRACE and ICESat mass changes during 2003–08. For EA, δB0 is −2.2 mm a−1 subsidence with mass matching at 150 Gt a−1, inland WA is −3.5 mm a−1 at 66 Gt a−1, and coastal WA is only −0.35 mm a−1 at −95 Gt a−1. WA subsidence is attributed to low mantle viscosity with faster responses to post-LGM deglaciation and to ice growth during Holocene grounding-line readvance. EA subsidence is attributed to Holocene dynamic thickening. With Antarctic Peninsula loss of −26 Gt a−1, the Antarctic total gain is 95 ± 25 Gt a−1 during 2003–08, compared to 144 ± 61 Gt a−1 from ERS1/2 during 1992–2001. Beginning in 2009, large increases in coastal WA dynamic losses overcame long-term EA and inland WA gains bringing Antarctica close to balance at −12 ± 64 Gt a−1 by 2012–16.

scholarly journals Sensitivity of Pine Island Glacier, West Antarctica, to changes in ice-shelf and basal conditions: a model study

2002 ◽  
Vol 48 (163) ◽  
pp. 552-558 ◽  
Author(s):  
Marjorie Schmeltz ◽  
Eric Rignot ◽  
Todd K. Dupont ◽  
Douglas R. MacAyeal
Keyword(s):  
Shear Stress ◽  
Element Model ◽  
Shelf Area ◽  
West Antarctica ◽  
Ice Shelf ◽  
Ice Stream ◽  
Model Study ◽  
Grounding Line ◽  
Glacier Velocity ◽  
Basal Shear

AbstractWe use a finite-element model of coupled ice-stream/ice-shelf flow to study the sensitivity of Pine Island Glacier, West Antarctica, to changes in ice-shelf and basal conditions. By tuning a softening coefficient of the ice along the glacier margins, and a basal friction coefficient controlling the distribution of basal shear stress underneath the ice stream, we are able to match model velocity to that observed with interferometric synthetic aperture radar (InSAR). We use the model to investigate the effect of small perturbations on ice flow. We find that a 5.5–13% reduction in our initial ice-shelf area increases the glacier velocity by 3.5–10% at the grounding line. The removal of the entire ice shelf increases the grounding-line velocity by > 70%. The changes in velocity associated with ice-shelf reduction are felt several tens of km inland. Alternatively, a 5% reduction in basal shear stress increases the glacier velocity by 13% at the grounding line. By contrast, softening of the glacier side margins would have to be increased a lot more to produce a comparable change in ice velocity. Hence, both the ice-shelf buttressing and the basal shear stress contribute significant resistance to the flow of Pine Island Glacier.

scholarly journals Interannual surface velocity variations of Pine Island Glacier, West Antarctica

2003 ◽  
Vol 36 ◽  
pp. 205-214 ◽  
Author(s):  
Bernhard T. Rabus ◽  
Oliver Lang
Keyword(s):  
Feature Tracking ◽  
Surface Velocity ◽  
Synthetic Aperture ◽  
Clear Correlation ◽  
West Antarctica ◽  
Velocity Increase ◽  
Grounding Line ◽  
Velocity Variations ◽  
Independent Confirmation ◽  
Observation Period

AbstractThe surface velocity of Pine Island Glacier, West Antarctica, during the period 1992–2000 is measured with synthetic aperture radar feature-tracking techniques. Over the observation period, we find a monotonic acceleration with a spatially uniform amplitude of about 12% of the surface velocity. The acceleration extends > 80 km inland of the grounding line into a zone of prominent arcuate crevasses.The upper limit of these crevasses has migrated up-glacier by 0.2 km a−1 correlated with a velocity increase of similar size in the crevassed zone. On the other hand, there is no clear correlation between the velocity variations and observations of grounding-line migration. These findings suggest ongoing dynamic thinning of Pine Island Glacier, providing independent confirmation of recent interferometric results obtained by Rignot and others (2002).

scholarly journals Sensitivity of the dynamics of Pine Island Glacier, West Antarctica, to climate forcing for the next 50 years

2014 ◽  
Vol 8 (5) ◽  
pp. 1699-1710 ◽  
Author(s):  
H. Seroussi ◽  
M. Morlighem ◽  
E. Rignot ◽  
J. Mouginot ◽  
E. Larour ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Three Dimensional ◽  
Major Contributor ◽  
West Antarctica ◽  
Climatic Impact ◽  
Ice Shelf ◽  
Ice Dynamics ◽  
Surface Mass ◽  
Grounding Line

Abstract. Pine Island Glacier, a major contributor to sea level rise in West Antarctica, has been undergoing significant changes over the last few decades. Here, we employ a three-dimensional, higher-order model to simulate its evolution over the next 50 yr in response to changes in its surface mass balance, the position of its calving front and ocean-induced ice shelf melting. Simulations show that the largest climatic impact on ice dynamics is the rate of ice shelf melting, which rapidly affects the glacier speed over several hundreds of kilometers upstream of the grounding line. Our simulations show that the speedup observed in the 1990s and 2000s is consistent with an increase in sub-ice-shelf melting. According to our modeling results, even if the grounding line stabilizes for a few decades, we find that the glacier reaction can continue for several decades longer. Furthermore, Pine Island Glacier will continue to change rapidly over the coming decades and remain a major contributor to sea level rise, even if ocean-induced melting is reduced.

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