Evolution of the East Antarctic Ice Sheet: A Numerical Study of Thermo-Mechanical Response Patterns With Changing Climate

An efficient numerical ice-sheet model, including time dependence and full thermo-mechanical coupling, has been developed in order to investigate the thermal regime and overall configuration of a polar ice sheet with respect to changing environmental conditions.From basic sensitivity experiments, in which a schematic East Antarctic ice sheet is forced with a typical glacial–interglacial climatic shift, it is found that: (i) the mutual interaction of temperature and deformation has a stabilizing effect on its steady-state configuration; (ii) in the transient mode, this climatic transition initially leads to increased ice thickness due to enhanced accumulation, after which this trend is reversed due to a warmer base. Time-scales for this reversal are of the order of 103 years in marginal zones and of 104 years in interior regions; (iii) horizontal heat advection plays a major role in damping possible runaway behaviour due to the dissipation – strain-rate feed-back, suggesting that creep instability is a rather unlikely candidate to initiate surging of the East Antarctic ice sheet.The model is then applied to four East Antarctic flow lines. Only the flow line passing through Wilkes Land appears to be vulnerable to widespread basal melting, due to enhanced basal warming following climatic warming. Time-dependent modelling of the Vostok flow line indicates that the Vostok Station area has risen about 95 m since the beginning of the present interglacial due to thermo-mechanical effects, which is of particular interest in interpreting the palaeoclimatic signal of the ice core obtained there.

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Evolution of the East Antarctic Ice Sheet: A Numerical Study of Thermo-Mechanical Response Patterns With Changing Climate

Annals of Glaciology ◽

10.1017/s0260305500006327 ◽

1988 ◽

Vol 11 ◽

pp. 52-59 ◽

Cited By ~ 58

Author(s):

P. Huybrechts ◽

J. Oerlemans

Keyword(s):

Mechanical Response ◽

Flow Line ◽

Numerical Study ◽

Ice Core ◽

Ice Sheet ◽

Antarctic Ice Sheet ◽

Mechanical Coupling ◽

Vostok Station ◽

Basal Melting ◽

East Antarctic Ice Sheet

An efficient numerical ice-sheet model, including time dependence and full thermo-mechanical coupling, has been developed in order to investigate the thermal regime and overall configuration of a polar ice sheet with respect to changing environmental conditions. From basic sensitivity experiments, in which a schematic East Antarctic ice sheet is forced with a typical glacial–interglacial climatic shift, it is found that: (i) the mutual interaction of temperature and deformation has a stabilizing effect on its steady-state configuration; (ii) in the transient mode, this climatic transition initially leads to increased ice thickness due to enhanced accumulation, after which this trend is reversed due to a warmer base. Time-scales for this reversal are of the order of 103 years in marginal zones and of 104 years in interior regions; (iii) horizontal heat advection plays a major role in damping possible runaway behaviour due to the dissipation – strain-rate feed-back, suggesting that creep instability is a rather unlikely candidate to initiate surging of the East Antarctic ice sheet. The model is then applied to four East Antarctic flow lines. Only the flow line passing through Wilkes Land appears to be vulnerable to widespread basal melting, due to enhanced basal warming following climatic warming. Time-dependent modelling of the Vostok flow line indicates that the Vostok Station area has risen about 95 m since the beginning of the present interglacial due to thermo-mechanical effects, which is of particular interest in interpreting the palaeoclimatic signal of the ice core obtained there.

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The Chemical Stratigraphy of Polar Ice Sheets — A Method of Dating Ice Cores

Journal of Glaciology ◽

10.3189/s0022143000011175 ◽

1981 ◽

Vol 27 (95) ◽

pp. 3-9

Author(s):

A. T. Wilson ◽

C. H. Hendy

Keyword(s):

Accumulation Rate ◽

Ice Core ◽

Ice Sheet ◽

Ice Cores ◽

Antarctic Ice Sheet ◽

The Core ◽

Similar Work ◽

Polar Ice Sheets ◽

Vostok Station ◽

East Antarctic Ice Sheet

AbstractStudies of the chemical stratigraphy in the snow near Vostok station, which is near the centre of the East Antarctic ice sheet, show that sodium exhibits annual concentration differences of up to a factor of ten. Similar work on the 952 m Vostok ice core enabled accumulation rates along selected parts of the core to be determined. This in turn enables the core to be dated. The accumulation rate in this central region of the East Antarctic ice sheet for the last 50000 years has been determined and is presented. An interesting result is that the accumulation rate during the last glacial period is only half that in post-glacial times. Results from the bottom of the core provide some evidence of a past surge in the East Antarctic ice sheet.

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The Chemical Stratigraphy of Polar Ice Sheets — A Method of Dating Ice Cores

Journal of Glaciology ◽

10.1017/s0022143000011175 ◽

1981 ◽

Vol 27 (95) ◽

pp. 3-9 ◽

Cited By ~ 15

Author(s):

A. T. Wilson ◽

C. H. Hendy

Keyword(s):

Accumulation Rate ◽

Ice Core ◽

Ice Sheet ◽

Ice Cores ◽

Antarctic Ice Sheet ◽

The Core ◽

Similar Work ◽

Polar Ice Sheets ◽

Vostok Station ◽

East Antarctic Ice Sheet

Abstract Studies of the chemical stratigraphy in the snow near Vostok station, which is near the centre of the East Antarctic ice sheet, show that sodium exhibits annual concentration differences of up to a factor of ten. Similar work on the 952 m Vostok ice core enabled accumulation rates along selected parts of the core to be determined. This in turn enables the core to be dated. The accumulation rate in this central region of the East Antarctic ice sheet for the last 50000 years has been determined and is presented. An interesting result is that the accumulation rate during the last glacial period is only half that in post-glacial times. Results from the bottom of the core provide some evidence of a past surge in the East Antarctic ice sheet.

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Limited Retreat of the Wilkes Basin Ice Sheet during the Last Interglacial.

10.5194/egusphere-egu2020-13504 ◽

2020 ◽

Author(s):

Johannes Sutter ◽

Olaf Eisen ◽

Martin Werner ◽

Klaus Grosfeld ◽

Thomas Kleiner ◽

...

Keyword(s):

Sea Level ◽

Ice Core ◽

Ice Sheet ◽

Last Interglacial ◽

Antarctic Ice Sheet ◽

Future Global Warming ◽

Grounding Line ◽

Ice Core Record ◽

East Antarctic Ice Sheet

The response of the marine sectors of the East Antarctic Ice Sheet to future global warming represents a major source of uncertainty in sea level projections. If greenhouse gas emissions continue unbridled, ice loss in these areas may contribute up to several meters to long-term global sea level rise. In East Antarctica, thinning of the ice cover of the George V and Sabrina Coast is currently taking place, and its destabilization in past warm climate periods has been implied. The extent of such past interglacial retreat episodes cannot yet be quantitatively derived from paleo proxy records alone. Ice sheet modelling constrained by paleo observations is therefore critical to assess the stability of the East Antarctic Ice Sheet during warmer climates. We propose that a runaway retreat during the Last Interglacial of the George V Coast grounding line into the Wilkes Subglacial Basin would either leave a clear imprint on the water isotope composition in the neighbouring Talos Dome ice-core record or prohibit the preservation of an ice core record from the Last Interglacial alltogether. We test this hypothesis using a dynamic ice sheet model and infer that the marine Wilkes Basin ice sheet remained stable throughout the Last Interglacial (130,000-120,000 years ago). Our analysis provides the first constraint on Last Interglacial East Antarctic grounding line stability by benchmarking ice sheet model simulations with ice core records. Our findings also imply that ambitious mitigation efforts keeping global temperature rise in check could safeguard this region from irreversible ice loss in the long term.

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The unique behavior of stable water isotopes profiles during interglacial periods at Talos Dome, Antarctica

10.5194/egusphere-egu21-1321 ◽

2021 ◽

Author(s):

Ilaria Crotti ◽

Amaelle Landais ◽

Barbara Stenni ◽

Massimo Frezzotti ◽

Aurélien Quiquet ◽

...

Keyword(s):

High Resolution ◽

Ice Core ◽

Ice Sheets ◽

Ice Sheet ◽

Surface Elevation ◽

Water Isotopes ◽

Antarctic Ice Sheet ◽

Moisture Sources ◽

Mis 5.5 ◽

East Antarctic Ice Sheet

The growth and decay of marine ice sheets act as important controls on regional and global climate, in particular, the behavior of the ice sheets is a key uncertainty in predicting sea-level rise during and beyond this century. The East Antarctic Ice Sheet (EAIS), which contains deep subglacial basins with reverse-sloping, is considered to be susceptible to ice loss caused by marine ice sheet instability. Sediment core offshore Wilkes Subglacial Basin reveals oscillations in the provenance of detrital sediment that have been interpreted to reflect an erosion of Wilkes Basin during interglacial periods MIS 5, MIS 7, and MIS 9 greater than Holocene period (Wilson et al., 2018). The aim of our study is to investigate past climate and environmental changes in the coastal area of the East Antarctic Ice Sheet during MIS 7.5 and 9.3 with the help of a new high-resolution water isotopes record of the TALDICE ice core.Here we present new &#948;18O and &#948;D high resolution (5 cm) records covering the oldest portion of the TALDICE ice core. MIS 7.5 and 9.3 isotopic signal reveals a unique feature, already observed for MIS 5.5, that has not been spotted in other Antarctic ice cores (Masson-Delmotte et al., 2011). Interglacial periods at TALDICE are characterized by a first peak, observed in correspondence to the culmination of the deglaciation event as for all Antarctic cores, followed by a less pronounced isotopic peak (for MIS 5.5 and 9.3) or a plateau (for MIS 7.5) prior to the glacial inception. Several factors might drive this peculiar behavior of the water stable isotopes record, as an increase in temperatures due to a drop in surface elevation or changes in moisture sources.The new &#948;18O and &#948;D high-resolution records for the TALDICE ice core reveal a unique pattern that characterizes interglacial periods at Talos Dome. Taking into account the coastal position of the core and its vicinity to the Wilkes Subglacial Basin we intend to investigate the possible decrease in surface elevation, through the application of the GRISLI ice sheet model (Quiquet et al., 2018), and changes in moisture sources, traceable from the d-excess record.

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