Organized flow from the South Pole to the Filchner-Ronne ice shelf: An assessment of balance velocities in interior East Antarctica using radio echo sounding data

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.

Download Full-text

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

Journal of Glaciology ◽

10.1017/s002214300003433x ◽

1975 ◽

Vol 15 (73) ◽

pp. 137-150 ◽

Cited By ~ 19

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.

Download Full-text

Forty-seven new subglacial lakes in the 0–110° E sector of East Antarctica

Journal of Glaciology ◽

10.3189/172756507782202856 ◽

2007 ◽

Vol 53 (181) ◽

pp. 289-297 ◽

Cited By ~ 33

Author(s):

Sergey V. Popov ◽

Valery N. Masolov

Keyword(s):

Heat Flux ◽

Scientific Work ◽

East Antarctica ◽

Lake Area ◽

Geothermal Heat ◽

Subglacial Lake ◽

Deep Faults ◽

Radio Echo Sounding ◽

Subglacial Lakes ◽

Echo Sounding

AbstractDuring the summer field seasons of 1987–91, studies of central East Antarctica by airborne radio-echo sounding commenced. This scientific work continued in the 1990s in the Vostok Subglacial Lake area and along the traverse route from Mirny, and led to the discovery of 16 new subglacial water cavities in the areas of Domes Fuji and Argus and the Prince Charles Mountains. Twenty-nine subglacial water cavities were revealed in the area near Vostok, along with a feature we believe to be a subglacial river. Two subglacial lakes were discovered along the Mirny–Vostok traverse route. These are located 50 km north of Komsomolskaya station and under Pionerskaya station. We find high geothermal heat flux in the vicinity of the largest of the subglacial lakes, and suggest this may be due to their location over deep faults where additional mantle heat is available.

Download Full-text

A revised inventory of Antarctic subglacial lakes

Antarctic Science ◽

10.1017/s0954102005002889 ◽

2005 ◽

Vol 17 (3) ◽

pp. 453-460 ◽

Cited By ~ 201

Author(s):

MARTIN J. SIEGERT ◽

SASHA CARTER ◽

IGNAZIO TABACCO ◽

SERGEY POPOV ◽

DONALD D. BLANKENSHIP

Keyword(s):

East Antarctica ◽

Large Lake ◽

Dome A ◽

Lake Vostok ◽

The Third ◽

The Us ◽

Radio Echo Sounding ◽

Subglacial Lakes ◽

Lake Type ◽

Echo Sounding

The locations and details of 145 Antarctic subglacial lakes are presented. The inventory is based on a former catalogue of lake-type features, which has been subsequently reanalysed, and on the results from three additional datasets. The first is from Italian radio-echo sounding (RES) of the Dome C region of East Antarctica, from which 14 new lakes are identified. These data also show that, in a number of occasions, multiple lake-type reflectors thought previously to be individual lakes are in fact reflections from the same relatively large lake. This reduces the former total of lake-type reflectors by six, but also adds a significant level of information to these particular lakes. The second dataset is from a Russian survey of the Dome A and Dome F regions of East Antarctica, which provides evidence of 18 new lakes and extends the coverage of the inventory considerably. The third dataset comprises three airborne RES surveys undertaken by the US in East Antarctica over the last five years, from which forty three new lakes have been identified. Reference to information on Lake Vostok, from Italian and US surveys taken in the last few years, is now included.

Download Full-text

Recent survey of brine infiltration in McMurdo Ice Shelf, Antarctica

Annals of Glaciology ◽

10.3189/1994aog20-1-215-218 ◽

1994 ◽

Vol 20 ◽

pp. 215-218 ◽

Cited By ~ 3

Author(s):

D. L. Morse ◽

E. D. Waddington

Keyword(s):

Shelf Break ◽

Recent Survey ◽

Ice Shelf ◽

Radio Echo Sounding ◽

Field Season ◽

Echo Sounding

The brine infiltration zone of Mc Murdo Ice Shelf, Antarctica, has been extensively studied by previous authors. Brine percolates inland laterally from the ice front, opposite to the direction of ice-shelf motion. Inland propagation of brine pulses following ice-shelf break-outs appears to be the primary brine-infiltration mechanism. During the 1992-93 field season, we used radio-echo sounding to resurvey the inland limit of the brine-infiltration zone. The boundary had been similarly mapped in 1977. We observed that since the earlier survey, one 7km section his retreated seaward by approximately 800 m while another 5 km section is unchanged. These displacements are consistent with the earlier hypothesis that brine infiltration occurs by the influx of brine pulses

Download Full-text

Basal Mass Balance Along a Flow Line on Ronne Ice Shelf, Antarctica (Abstract)

Annals of Glaciology ◽

10.1017/s0260305500006583 ◽

1988 ◽

Vol 11 ◽

pp. 201

Author(s):

A. Jenkins ◽

C.S.M. Doake

Keyword(s):

Steady State ◽

Mass Balance ◽

Flow Line ◽

Average Rate ◽

Ice Shelf ◽

Grounding Line ◽

Radio Echo Sounding ◽

State Models ◽

Basal Melting ◽

Echo Sounding

Recent glaciological work on Ronne Ice Shelf has focused on an assumed flow line which extends from Rutford Ice Stream grounding line to the ice front. Results from doppler satellite surveying and radio echo-sounding are used in kinematic calculations to determine the basal mass balance, assuming the flow line to be in a steady state. Models suggest that basal melting dominates over most of the flow line and is most pronounced at the extremities. In the region within 300 km of the grounding line and over the final 45 km before the ice front, at least 1 m/a on average must melt away to maintain the observed velocity and thickness profile. More gentle melting occurs over about half the remaining distance, but in a region between 130 and 300 km in from the ice front, basal freezing must occur at an average rate of about 0.1 m/a to maintain a steady state. The existence of a thin layer of saline ice underlying the ice shelf, which persists for a further 80 km down-stream before being melted away entirely, is consistent with the weak returns observed during both airborne and ground-based radio echo-sounding in this region.

Download Full-text

Why didn't they ask Evans?: a response to Karen May

Polar Record ◽

10.1017/s0032247418000220 ◽

2018 ◽

Vol 54 (2) ◽

pp. 178-180 ◽

Cited By ~ 1

Author(s):

Chris S.M. Turney

Keyword(s):

South Pole ◽

The South ◽

Ice Shelf ◽

Ross Ice Shelf ◽

Geographical Society ◽

Antarctic Expedition ◽

Early Departure ◽

The Uk

In ’Why didn't they ask Evans?’ (Turney, 2017), I draw together previously unpublished sources and new analyses of published material to cast further light on the circumstances that led to the fatal events surrounding the return of Captain Robert Falcon Scott's Polar Party on the British Antarctic Expedition (BAE, 1911–1913). Of particular importance are the notes on the meeting between the Royal Geographical Society's President Lord Curzon and the widows Kathleen Scott and Oriana Wilson in April 1913, which explicitly identify Lieutenant Edward ‘Teddy’ Evans as having removed food that exceeded his allocation as a member of the Last Supporting Party (Curzon, 1913), the establishment and almost immediate closure of a ‘Committee of Enquiry’ chaired by Lord Curzon (Beaumont, 1913a, b, c; Cherry-Garrard, 1913a; Darwin, 1913; Goldie, 1913), the recognition of missing food at key depots by the returning Polar Party on the 7, 24 and 27 February 1912 (Scott, 1913a; Wilson, 1912), Evans’ anger at not being selected as a member of the Polar Party and his early departure home (Evans, 1912), the revised timeline of when Evans fell down with scurvy on the Ross Ice Shelf to apparently align with when and where the food was removed (The Advertiser, 3 April 1912, Adelaide: 10) (Cherry-Garrard, 1922; Ellis, 1969; Evans, 1912, 1913a, 1943; Lashly, 1912; Scott, 1913a, 1913b), Evans’ failure to ensure Scott's orders regarding the return of the dog sledging teams had been acted on (Cherry-Garrard, 1922; Gran, 1961; Hattersley-Smith & McGhie, 1984) and the misunderstanding amongst senior Royal Geographical Society members during Evans’ recuperation in the UK that Apsley Cherry-Garrard ‘was to meet the South Pole party, with two teams of dogs, at the foot of the [Beardmore] glacier’ (Markham, 1913). I would like to thank May (2018) for her comment and acknowledge that Edward Wilson's sketchbooks of the expedition's logistics, scientific priorities, sketches and notes on the BAE comprise entries from 1911–1912 and not solely from 1912, which Turney (2017) used to denote the year of the last entry.

Download Full-text

The Dynamics of the Ross Ice Shelf Revealed by Radio Echo-Sounding

Journal of Glaciology ◽

10.1017/s0022143000014817 ◽

1979 ◽

Vol 24 (90) ◽

pp. 295-307 ◽

Cited By ~ 95

Author(s):

C. S. Neal

Keyword(s):

Dielectric Loss ◽

Water Interface ◽

Ice Shelf ◽

Flow Lines ◽

Regional Variations ◽

Distinctive Features ◽

Ross Ice Shelf ◽

Radio Echo Sounding ◽

Ice Water ◽

Echo Sounding

AbstractRadio-echo data have yielded information on the dynamics of the Ross Ice Shelf. Distinctive features present on the radio-echo records have been used to delineate several flow lines on the ice shelf. Measurement of the power returned from the ice-water interface has revealed regional variations in the r.f. dielectric loss of Ross Ice Shelf ice. These variations are used to indicate zones of bottom melting and freezing.

Download Full-text

Past and present accumulation rate reconstruction along the Dome Fuji–Kohnen radio-echo sounding profile, Dronning Maud Land, East Antarctica

Annals of Glaciology ◽

10.3189/172756409789097513 ◽

2009 ◽

Vol 50 (51) ◽

pp. 112-120 ◽

Cited By ~ 20

Author(s):

Philippe Huybrechts ◽

Oleg Rybak ◽

Daniel Steinhage ◽

Frank Pattyn

Keyword(s):

Accumulation Rate ◽

Inversion Layer ◽

Three Dimensional ◽

East Antarctica ◽

Condensation Temperature ◽

Accumulation Rates ◽

Thermomechanical Model ◽

Radio Echo Sounding ◽

Dronning Maud Land ◽

Echo Sounding

AbstractWe used internal ice layers from a radio-echo sounding profile between the Kohnen and Dome Fuji deep drilling sites to infer the spatio-temporal pattern of accumulation rate in this sector of Dronning Maud Land, East Antarctica. Continuous internal reflection horizons can be traced to about half of the ice thickness and have a maximum age of approximately 72.7 ka BP. To infer palaeo-accumulation rates from the dated layers, we derived the thinning functions from a flow calculation with a high-resolution higher-order model of Dronning Maud Land embedded into a three-dimensional thermomechanical model of the Antarctic ice sheet. The method takes into account complex ice-flow dynamics and advection effects that cannot be dealt with using traditional local approaches. We selected seven time intervals over which we determine the average accumulation rate and average surface temperature at the place and time of origin of the layer particles. Our results show lower accumulation rates along eastern parts of the profile for the late Holocene (0–5 ka BP) than are shown by existing maps, which had no surface control points. During the last glacial period we find a substantially lower accumulation rate than predicted by the usual approach linking palaeo-accumulation rates to the condensation temperature above the surface inversion layer. These findings were used to fine-tune the relation between accumulation rate and temperature.

Download Full-text

Basal Mass Balance Along a Flow Line on Ronne Ice Shelf, Antarctica (Abstract)

Annals of Glaciology ◽

10.3189/s0260305500006583 ◽

1988 ◽

Vol 11 ◽

pp. 201-201

Author(s):

A. Jenkins ◽

C.S.M. Doake

Keyword(s):

Steady State ◽

Mass Balance ◽

Flow Line ◽

Average Rate ◽

Ice Shelf ◽

Grounding Line ◽

Radio Echo Sounding ◽

State Models ◽

Basal Melting ◽

Echo Sounding

Recent glaciological work on Ronne Ice Shelf has focused on an assumed flow line which extends from Rutford Ice Stream grounding line to the ice front. Results from doppler satellite surveying and radio echo-sounding are used in kinematic calculations to determine the basal mass balance, assuming the flow line to be in a steady state. Models suggest that basal melting dominates over most of the flow line and is most pronounced at the extremities. In the region within 300 km of the grounding line and over the final 45 km before the ice front, at least 1 m/a on average must melt away to maintain the observed velocity and thickness profile. More gentle melting occurs over about half the remaining distance, but in a region between 130 and 300 km in from the ice front, basal freezing must occur at an average rate of about 0.1 m/a to maintain a steady state. The existence of a thin layer of saline ice underlying the ice shelf, which persists for a further 80 km down-stream before being melted away entirely, is consistent with the weak returns observed during both airborne and ground-based radio echo-sounding in this region.

Download Full-text