scholarly journals Ice Cover, Subglacial Landscape, and Estimation of Bottom Melting of Mac. Robertson, Princess Elizabeth, Wilhelm II, and Western Queen Mary Lands, East Antarctica

2022 ◽  
Vol 14 (1) ◽  
pp. 241
Author(s):  
Sergey Popov
Keyword(s):  
Sea Level ◽  
Field Research ◽  
Research Area ◽  
Melting Rate ◽  
East Antarctica ◽  
Ice Thickness ◽  
Radio Echo Sounding ◽  
Base Elevation ◽  
Vast Area ◽  
Grove Mountains

This study demonstrates the results of Russian airborne radio-echo sounding (RES) investigations and also seismic reflection soundings carried out in 1971–2020 over a vast area of coastal part of East Antarctica. It is the first comprehensive summary mapping of these data. Field research, equipment, errors of initial RES data, and methods of gridding are discussed. Ice thickness, ice base elevation, and bedrock topography are presented. The ice thickness across the research area varies from a few meters to 3620 m, and is greatest in the local subglacial depressions. The average thickness is about 1220 m. The total volume of the ice is about 710,500 km3. The bedrock heights vary from 2860 m below sea level in the ocean bathyal zone to 2040 m above sea level in the Grove Mountains area (4900 m relief). The main directions of the bedrock orographic forms are concentrated mostly in three intervals: 345∘–30∘, 45∘–70∘, and 70∘–100∘. The bottom melting rate was estimated on the basis of the simple Zotikov model. Total annual melting under the study area is about 0.633 cubic meters. The total annual melting in the study area is approximately 1.5 mm/yr.

scholarly journals Refined broad-scale sub-glacial morphology of Aurora Subglacial Basin, East Antarctica derived by an ice-dynamics-based interpolation scheme

2011 ◽  
Vol 5 (3) ◽  
pp. 551-560 ◽  
Author(s):  
J. L. Roberts ◽  
R. C. Warner ◽  
D. Young ◽  
A. Wright ◽  
T. D. van Ommen ◽  
...  
Keyword(s):  
Sea Level ◽  
Ice Sheet ◽  
East Antarctica ◽  
Geometric Constraints ◽  
Ice Thickness ◽  
Interpolation Scheme ◽  
Ice Dynamics ◽  
High Resolution Data ◽  
Physically Based ◽  
Glacial Morphology

Abstract. Ice thickness data over much of East Antarctica are sparse and irregularly distributed. This poses difficulties for reconstructing the homogeneous coverage needed to properly assess underlying sub-glacial morphology and fundamental geometric constraints on sea level rise. Here we introduce a new physically-based ice thickness interpolation scheme and apply this to existing ice thickness data in the Aurora Subglacial Basin region. The skill and robustness of the new reconstruction is demonstrated by comparison with new data from the ICECAP project. The interpolated morphology shows an extensive marine-based ice sheet, with considerably more area below sea-level than shown by prior studies. It also shows deep features connecting the coastal grounding zone with the deepest regions in the interior. This has implications for ice sheet response to a warming ocean and underscores the importance of obtaining additional high resolution data in these marginal zones for modelling ice sheet evolution.

scholarly journals Refined broad-scale sub-glacial morphology of Aurora Subglacial Basin, East Antarctica derived by an ice-dynamics-based interpolation scheme

2011 ◽  
Vol 5 (1) ◽  
pp. 655-684 ◽  
Author(s):  
J. L. Roberts ◽  
R. C. Warner ◽  
D. Young ◽  
A. Wright ◽  
T. D. van Ommen ◽  
...  
Keyword(s):  
Sea Level ◽  
Ice Sheet ◽  
East Antarctica ◽  
Geometric Constraints ◽  
Ice Thickness ◽  
Interpolation Scheme ◽  
Ice Dynamics ◽  
High Resolution Data ◽  
Physically Based ◽  
Glacial Morphology

Abstract. Ice thickness data over much of East Antarctica are sparse and irregularly distributed. This poses difficulties for reconstructing the homogeneous coverage needed to properly assess underlying sub-glacial morphology and fundamental geometric constraints on sea level rise. Here we introduce a new physically-based ice thickness interpolation scheme and apply this to existing ice thickness data in the Aurora Subglacial Basin region. The skill and robustness of the new reconstruction is demonstrated by comparison with new data from the ICECAP project. The interpolated morphology shows an extensive marine-based ice sheet, with considerably more area below sea-level than shown by prior studies. It also shows deep features connecting the coastal grounding zone with the deepest regions in the interior. This has implications for ice sheet response to a warming ocean and underscores the importance of obtaining additional high resolution data in these marginal zones for modelling ice sheet evolution.

scholarly journals Comparison of Electromagnetic and Seismic-Gravity Ice Thickness Measurements in East Antarctica

1975 ◽  
Vol 15 (73) ◽  
pp. 137-150 ◽  
Author(s):  
David J. Drewry
Keyword(s):  
Seismic Reflection ◽  
East Antarctica ◽  
Ice Thickness ◽  
South Pole ◽  
Victoria Land ◽  
Radio Echo Sounding ◽  
Mean Differences ◽  
Thickness Measurements ◽  
Better Than ◽  
Echo Sounding

AbstractThe errors involved in ice thickness determinations in Antarctica by seismic reflection shooting, gravity observations and radio-echo sounding are briefly discussed. Relative accuracies of 3%, 7-10% and 1.5% have been suggested. Double checks of ice depths from radar sounding in east Antarctica indicate an internal consistency of measurement for this technique of <1%. Comparison of carefully executed seismic shooting and routine radio-echo sounding results against absolute ice thickness values from two deep core drilling sites show no significant differences between these two remote methods (i.e. both are better than 1.5%).Over 60 comparisons are examined between radar ice thicknesses and over-snow measurements obtained on eight independent traverses in east Antarctica. Three traverses exhibit consistently unacceptable results-U.S. Victoria Land Traverse II (southern leg), Commonwealth Transanlarctic Expedition and the U.S.S.R. Vostok to South Pole Traverse—which probably result from misinterpretation of “noisy” seismograms. The remaining comparisons indicate mean differences, including some navigational uncertainty, of ≈3%, <8% and 5% between radio-echo and (1) seismic, (2) gravity, and (3) gravity tied to seismic determinations, respectively.

An inventory of Antarctic sub-glacial lakes

1996 ◽  
Vol 8 (3) ◽  
pp. 281-286 ◽  
Author(s):  
M.J. Siegert ◽  
J.A. Dowdeswell ◽  
M.R. Gorman ◽  
N.F. McIntyre
Keyword(s):  
Ice Sheet ◽  
East Antarctica ◽  
Glacial Lake ◽  
Ice Thickness ◽  
Minimum Length ◽  
Glacial Lakes ◽  
University Of Cambridge ◽  
Radio Echo Sounding ◽  
Polar Research Institute ◽  
Lake Type

An extensive analogue database of 60 MHz radio-echo sounding records of Antarctica (covering 50% of the ice sheet) is held at the Scott Polar Research Institute, University of Cambridge. This database was analysed in order to determine the presence and location of Antarctic sub-glacial lakes. In total, 77 sub-glacial lake-type records were identified, 13 more than detected in previous studies. An inventory of these sub-glacial lakes includes geographical coordinates, minimum length and overlying ice thickness for each lake. Information concerning the location of these lakes indicates that the majority (~70%) are found in the proximity of ice divides at Dome C and Ridge B within East Antarctica.

scholarly journals Basal conditions beneath enhanced-flow tributaries of Slessor Glacier, East Antarctica

2006 ◽  
Vol 52 (179) ◽  
pp. 481-490 ◽  
Author(s):  
D.M. Rippin ◽  
J.L. Bamber ◽  
M.J. Siegert ◽  
D.G. Vaughan ◽  
H.F.J. Corr
Keyword(s):  
Sea Level ◽  
Marine Sediments ◽  
East Antarctica ◽  
Flow Rates ◽  
The Past ◽  
Radio Echo Sounding ◽  
Slow Moving ◽  
Bed Roughness ◽  
Rough Beds ◽  
Interesting Area

AbstractRadio-echo sounding data are used to investigate bed roughness beneath the three enhanced-flow tributaries of Slessor Glacier, East Antarctica. Slow-moving inter-tributary areas are found to have rough beds, while the bed of the northernmost tributary is relatively smooth. A reconstruction of potential subglacial drainage routing indicates that water would be routed down this tributary, and investigations of basal topography following isostatic recovery reveal that the bed would have been below sea level in preglacial times, so marine sediments may have accumulated here. Together, these factors are further support for the dominance of basal motion in this tributary, reported elsewhere. Conversely, although the other two Slessor tributaries may have water routed beneath them, they would not have been below sea level before the growth of the ice sheet, so cannot be underlain by marine sediments. They are also found to be rough, and, within the range of uncertainties, it is likely that basal motion does not play a major role in the flow of these tributaries. Perhaps the most interesting area, however, is a deep trough where flow rates are currently low but the bed is as smooth as the northern Slessor trough. It is proposed that, although ice deformation currently dominates in this trough, basal motion may have occurred in the past, when the ice was thicker.

scholarly journals The role of ice thickness and bed properties on the dynamics of the enhanced-flow tributaries of Bailey Ice Stream and Slessor Glacier, East Antarctica

2004 ◽  
Vol 39 ◽  
pp. 366-372 ◽  
Author(s):  
David M. Rippin ◽  
Jonathan L. Bamber ◽  
Martin J. Siegert ◽  
David G. Vaughan ◽  
Hugh F. J. Corr
Keyword(s):  
Numerical Modelling ◽  
Significant Proportion ◽  
East Antarctica ◽  
Ice Thickness ◽  
Ice Stream ◽  
Radio Echo Sounding ◽  
Basal Reflection ◽  
Echo Sounding ◽  
Modelling Study

AbstractAirborne radio-echo sounding investigations in the upper reaches of Bailey Ice Stream and Slessor Glacier, Coats Land, East Antarctica, have shown that enhanced-flow tributaries are associated with well-defined areas of relatively thicker ice, and are separated from each other by areas of relatively thinner ice. A numerical modelling study has revealed that while internal ice deformation might account for all the observed flow in inter-tributary areas and the majority in the Slessor tributaries, a significant proportion of the flow of Bailey tributary is attributable to basal motion. Further, investigations of depth-corrected basal reflection power indicate that the bed underlying both Bailey and Slessor enhanced-flow tributaries is significantly smoother than in the slower-moving inter-tributary areas. It is thus proposed that enhanced motion within Bailey tributary (and also perhaps Slessor) may be facilitated by a reduction in basal roughness, caused by the accumulation of water and/or sediments within subglacial valleys, or by the erosion and smoothing of bed obstacles.

scholarly journals Subglacial topography and ice flux along the English Coast of Palmer Land, Antarctic Peninsula

2020 ◽  
Vol 12 (4) ◽  
pp. 3453-3467
Author(s):  
Kate Winter ◽  
Emily A. Hill ◽  
G. Hilmar Gudmundsson ◽  
John Woodward
Keyword(s):  
Sea Level ◽  
Surface Velocity ◽  
Ice Thickness ◽  
Ice Streams ◽  
Ice Flow ◽  
Grounding Line ◽  
Line Spacing ◽  
Radio Echo Sounding ◽  
Subglacial Topography ◽  
The Uk

Abstract. Recent satellite data have revealed widespread grounding line retreat, glacier thinning, and associated mass loss along the Bellingshausen Sea sector, leading to increased concern for the stability of this region of Antarctica. While satellites have greatly improved our understanding of surface conditions, a lack of radio-echo sounding (RES) data in this region has restricted our analysis of subglacial topography, ice thickness, and ice flux. In this paper we analyse 3000 km of 150 MHz airborne RES data collected using the PASIN2 radar system (flown at 3–5 km line spacing) to investigate the subglacial controls on ice flow near the grounding lines of Ers, Envisat, Cryosat, Grace, Sentinel, Lidke, and Landsat ice streams as well as Hall and Nikitin glaciers. We find that each outlet is topographically controlled, and when ice thickness is combined with surface velocity data from MEaSUREs (Mouginot et al., 2019a), these outlets are found to discharge over 39.25 ± 0.79 Gt a−1 of ice to floating ice shelves and the Southern Ocean. Our RES measurements reveal that outlet flows are grounded more than 300 m below sea level and that there is limited topographic support for inland grounding line re-stabilization in a future retreating scenario, with several ice stream beds dipping inland at ∼ 5∘ km−1. These data reinforce the importance of accurate bed topography to model and understand the controls on inland ice flow and grounding line position as well as overall mass balance and sea level change estimates. RES data described in this paper are available through the UK Polar Data Centre: https://doi.org/10.5285/E07D62BF-D58C-4187-A019-59BE998939CC (Corr and Robinson, 2020).

scholarly journals Radio Echo Sounding (RES) investigations at Talos Dome (East Antarctica): bedrock topography and ice thickness

2009 ◽  
Vol 46 (6) ◽  
Author(s):  
C. Bianchi ◽  
L. Cafarella ◽  
P. De Michelis ◽  
A. Forieri ◽  
M. Frezzotti ◽  
...  
Keyword(s):  
East Antarctica ◽  
Ice Thickness ◽  
Bedrock Topography ◽  
Radio Echo Sounding ◽  
Echo Sounding

scholarly journals Bed topography of Princess Elizabeth Land in East Antarctica

2020 ◽  
Author(s):  
Xiangbin Cui ◽  
Hafeez Jeofry ◽  
Jamin S. Greenbaum ◽  
Jingxue Guo ◽  
Lin Li ◽  
...  
Keyword(s):  
Gravity Data ◽  
Mass Conservation ◽  
East Antarctica ◽  
Ice Thickness ◽  
Surface Model ◽  
Hydraulic Pressure ◽  
Satellite Gravity ◽  
Free Zone ◽  
Ice Surface ◽  
Radio Echo Sounding

Abstract. We present a topographic digital elevation model (DEM) for Princess Elizabeth Land (PEL), East Antarctica – the last remaining region in Antarctica to be surveyed by airborne radio-echo sounding (RES) techniques. The DEM covers an area of ~900,000 km2 and was established from new RES data collected by the ICECAP-2 consortium, led by the Polar Research Institute of China, from four campaigns since 2015. Previously, the region (along with Recovery basin elsewhere in East Antarctica) was characterised by an inversion using low resolution satellite gravity data across a large (>200 km wide) data-free zone to generate the Bedmap2 topographic product. We use the mass conservation (MC) method to produce an ice thickness grid across faster-flowing (>30 m yr-1) regions of the ice sheet and streamline diffusion in slower-flowing areas. The resulting ice thickness model is integrated with an ice surface model to build the bed DEM. With the revised bed DEM, we are able to model the flow of subglacial water and assess where the hydraulic pressure, and hydrological routing, is most sensitive to small ice-surface gradient changes. Together with BedMachine Antarctica, and Bedmap2, this new PEL bed DEM completes the first order measurement of subglacial continental Antarctica – an international mission that began around 70 years ago. The ice thickness and bed elevation DEMs of PEL (resolved horizontally at 500 m relative to ice surface elevations obtained from a combination of European Remote Sensing Satellite 1 radar (ERS-1) and Ice, Cloud and Land Elevation Satellite (ICESat) laser satellite altimetry datasets) are accessible from https://doi.org/10.5281/zenodo.3666088 (Cui et 38al., 2020).

scholarly journals Ice thickness, internal structure and subglacial topography of Bowles Plateau ice cap and the main ice divides of Livingston Island, Antarctica, by ground-based radio-echo sounding

2009 ◽  
Vol 50 (51) ◽  
pp. 49-56 ◽  
Author(s):  
Yu.Ya. Macheret ◽  
J. Otero ◽  
F.J. Navarro ◽  
E.V. Vasilenko ◽  
M.I. Corcuera ◽  
...  
Keyword(s):  
Internal Structure ◽  
Sea Level ◽  
Low Frequency ◽  
South Shetland Islands ◽  
Ice Thickness ◽  
Radio Waves ◽  
Ice Cap ◽  
Livingston Island ◽  
Radio Echo Sounding ◽  
Echo Sounding

AbstractWe present the results of low-frequency (20 MHz) radio-echo sounding (RES) carried out in December 2000 and December 2006 on the main ice divides of Livingston Island, South Shetland Islands (SSI), Antarctica, and Bowles Plateau, Antarctica, respectively, as well as high-frequency (200 MHz) RES on the latter, aimed at determining the ice thickness, internal structure and subglacial relief. Typical ice thickness along the main ice divides is ~150 m, reaching maxima of ~200 m. On Bowles Plateau the ice is much thicker, with an average of 265 m and maxima of ~500 m. The bed below the main ice divides is above sea level, while part of the outlet glaciers from Bowles Plateau lies significantly below sea level, down to –120 m. The strong scattering of the radio waves in the areas under study constitutes further evidence that the ice in the accumulation area of the ice masses of the SSI is temperate. Typical thickness of the firn layer in Bowles Plateau is 20–35 m, similar to that found in King George ice cap. A strong internal reflector within the firn layer, interpreted as a tephra layer from the 1970 eruption at Deception Island, has allowed a rough estimate of the specific mass balances for Bowles Plateau within 0.20–0.40ma–1w.e., as average values for the period 1970–2006.

Sign in / Sign up

Export Citation Format

Share Document