Radio Echo Determination of Basal Roughness Characteristics on the Ross Ice Shelf

The small-scale roughness characteristics of the bottom surface of the Ross Ice Shelf (RIS) are determined at two locations using airborne radio echo-sounding results. Small-scale roughness is not resolvable by an echo sounder, but may be quantified by examination of the fading pattern of the received echo. A full interpretation of the bottom echo requires a knowledge of the modulation imposed upon the radar signal by the ice/air boundary. This is obtained by determining the roughness scales of the ice-shelf surface. Its effect on estimates of basal roughness is investigated and is found to be unimportant in most cases.

Investigation of Sub-Ice Bedrock Characteristics by Radio-Echo Sounding

10.3189/s0022143000034286 ◽

1975 ◽

Vol 15 (73) ◽

pp. 75-87 ◽

Cited By ~ 1

Author(s):

G. K. A. Oswald

Keyword(s):

Surface Characteristics ◽

Bottom Surface ◽

Small Scale ◽

Devon Island ◽

Quantitative Studies ◽

Base Camp ◽

Surface Slopes ◽

Radio Echo Sounding ◽

Basal Melting ◽

AbstractQualitative inspection of the results of the 1971/72 S.P.R.I.-N.S.F. Antarctic radio-echo sounding programme shows that it is possible to infer some characteristics of the lower face of the ice from the form of received echoes. We confirm the existence of lakes of liquid water beneath the east Antarctic ice by inspection of the top and bottom surface gradients of the ice, and suggest that basal melting occurs over a wide area in this region.Quantitative studies in Devon Island indicate that small-scale irregularities in the bedrock are characterized by slopes of about 1: 40, with some higher gradients present, possibly indicating the presence of morainal boulders. We deduce that a geological boundary was crossed between 25 and 40 km west of the base camp, the rock to the west of the boundary having lower permittivity, and higher surface slopes than that to the east.The question of the usefulness of the spatial fading of the echo in deducing surface characteristics is briefly discussed. We conclude that measurements of the fading are indeed useful, especially in the case of echoes with short “tails”.

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

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 ◽

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.

Investigation of Sub-Ice Bedrock Characteristics by Radio-Echo Sounding

10.1017/s0022143000034286 ◽

1975 ◽

Vol 15 (73) ◽

pp. 75-87 ◽

Cited By ~ 45

Author(s):

G. K. A. Oswald

Keyword(s):

Surface Characteristics ◽

Bottom Surface ◽

Small Scale ◽

Devon Island ◽

Quantitative Studies ◽

Base Camp ◽

Surface Slopes ◽

Radio Echo Sounding ◽

Basal Melting ◽

Abstract Qualitative inspection of the results of the 1971/72 S.P.R.I.-N.S.F. Antarctic radio-echo sounding programme shows that it is possible to infer some characteristics of the lower face of the ice from the form of received echoes. We confirm the existence of lakes of liquid water beneath the east Antarctic ice by inspection of the top and bottom surface gradients of the ice, and suggest that basal melting occurs over a wide area in this region. Quantitative studies in Devon Island indicate that small-scale irregularities in the bedrock are characterized by slopes of about 1: 40, with some higher gradients present, possibly indicating the presence of morainal boulders. We deduce that a geological boundary was crossed between 25 and 40 km west of the base camp, the rock to the west of the boundary having lower permittivity, and higher surface slopes than that to the east. The question of the usefulness of the spatial fading of the echo in deducing surface characteristics is briefly discussed. We conclude that measurements of the fading are indeed useful, especially in the case of echoes with short “tails”.

Characteristics of Ice Flow in Marie Byrd Land, Antarctica

10.3189/s0022143000014659 ◽

1979 ◽

Vol 24 (90) ◽

pp. 63-75 ◽

Cited By ~ 2

Author(s):

K. E. Rose

Keyword(s):

Flow Line ◽

Landsat Imagery ◽

Ice Sheet ◽

West Antarctica ◽

Ice Shelf ◽

Ice Streams ◽

Ice Flow ◽

Ross Ice Shelf ◽

Radio Echo Sounding ◽

AbstractExtensive radio echo-sounding has mapped the part of West Antarctica between Byrd Station, the Whitmore Mountains, the Transantarctic Mountains, and the Ross Ice Shelf. The ice sheet in this area is dominated by five major sub-parallel ice streams (A–E), which are up to 100 km wide and extend inland from the grounding line of the Ross Ice Shelf for about 400 km. Their positions have been determined by crevassing seen on radio echo-sounding records, trimetrogon photographs, and Landsat imagery. The ice streams are characterized by their flat transverse cross-sections, while the intervening ice sheet exhibits domes and ridges. Ice flow lines are defined from the ice-surface contour pattern and the trend of the ice streams. It is apparent from this work that the flow line passing through Byrd Station joins ice stream D.The bedrock of the area is relatively smooth near the Ross Ice Shelf, becoming rougher near Byrd Station and especially so near the Whitmore Mountains. Bedrock troughs, which control the positions of the ice streams, are believed to have a tectonic origin.In this paper the role of the ice streams in the glaciological regime of West Antarctica is investigated from radio-echo data and estimates of balance velocity, basal shear stress, and basal temperatures.

Bottom Crevasses in the Ross Ice Shelf

10.1017/s0022143000034560 ◽

1975 ◽

Vol 15 (73) ◽

pp. 457-458 ◽

Cited By ~ 5

Author(s):

John W. Clough

Keyword(s):

Austral Summer ◽

Wide Angle ◽

Velocity Measurements ◽

Ice Shelf ◽

Linear Features ◽

Ross Ice Shelf ◽

Radio Echo Sounding ◽

Bottom crevasses were detected at many locations in the southern portion of the Ross Ice Shelf during the 1973-74 austral summer. The crevasses which extended up about 100 m from the bottom of the shelf were detected by radio-echo sounding. These linear features were mapped in some detail at the RISP Camp. Wide-angle reflection velocity measurements, airborne radio-echo sounding, and other results of the R1GGS program will be included in the discussion.

Characteristics of Ice Flow in Marie Byrd Land, Antarctica

10.1017/s0022143000014659 ◽

1979 ◽

Vol 24 (90) ◽

pp. 63-75 ◽

Cited By ~ 188

Author(s):

K. E. Rose

Keyword(s):

Flow Line ◽

Landsat Imagery ◽

Ice Sheet ◽

West Antarctica ◽

Ice Shelf ◽

Ice Streams ◽

Ice Flow ◽

Ross Ice Shelf ◽

Radio Echo Sounding ◽

AbstractExtensive radio echo-sounding has mapped the part of West Antarctica between Byrd Station, the Whitmore Mountains, the Transantarctic Mountains, and the Ross Ice Shelf. The ice sheet in this area is dominated by five major sub-parallel ice streams (A–E), which are up to 100 km wide and extend inland from the grounding line of the Ross Ice Shelf for about 400 km. Their positions have been determined by crevassing seen on radio echo-sounding records, trimetrogon photographs, and Landsat imagery. The ice streams are characterized by their flat transverse cross-sections, while the intervening ice sheet exhibits domes and ridges. Ice flow lines are defined from the ice-surface contour pattern and the trend of the ice streams. It is apparent from this work that the flow line passing through Byrd Station joins ice stream D.The bedrock of the area is relatively smooth near the Ross Ice Shelf, becoming rougher near Byrd Station and especially so near the Whitmore Mountains. Bedrock troughs, which control the positions of the ice streams, are believed to have a tectonic origin.In this paper the role of the ice streams in the glaciological regime of West Antarctica is investigated from radio-echo data and estimates of balance velocity, basal shear stress, and basal temperatures.

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

10.3189/s0022143000014817 ◽

1979 ◽

Vol 24 (90) ◽

pp. 295-307 ◽

Cited By ~ 3

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 ◽

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.

Bottom Crevasses in the Ross Ice Shelf

10.3189/s0022143000034560 ◽

1975 ◽

Vol 15 (73) ◽

pp. 457-458

Author(s):

John W. Clough

Keyword(s):

Austral Summer ◽

Wide Angle ◽

Velocity Measurements ◽

Ice Shelf ◽

Linear Features ◽

Ross Ice Shelf ◽

Radio Echo Sounding ◽

Bottom crevasses were detected at many locations in the southern portion of the Ross Ice Shelf during the 1973-74 austral summer. The crevasses which extended up about 100 m from the bottom of the shelf were detected by radio-echo sounding. These linear features were mapped in some detail at the RISP Camp. Wide-angle reflection velocity measurements, airborne radio-echo sounding, and other results of the R1GGS program will be included in the discussion.

New determinations of tides on the north-western Ross Ice Shelf

Antarctic Science ◽

10.1017/s0954102020000498 ◽

2020 ◽

pp. 1-14

Author(s):

Richard D. Ray ◽

Kristine M. Larson ◽

Bruce J. Haines

Keyword(s):

Time Series ◽

Tide Gauge ◽

High Rate ◽

Ice Shelf ◽

Ross Ice Shelf ◽

The North ◽

Global Positioning ◽

North Western

Abstract New determinations of ocean tides are extracted from high-rate Global Positioning System (GPS) solutions at nine stations sitting on the Ross Ice Shelf. Five are multi-year time series. Three older time series are only 2–3 weeks long. These are not ideal, but they are still useful because they provide the only in situ tide observations in that sector of the ice shelf. The long tide-gauge observations from Scott Base and Cape Roberts are also reanalysed. They allow determination of some previously neglected tidal phenomena in this region, such as third-degree tides, and they provide context for analysis of the shorter datasets. The semidiurnal tides are small at all sites, yet M2 undergoes a clear seasonal cycle, which was first noted by Sir George Darwin while studying measurements from the Discovery expedition. Darwin saw a much larger modulation than we observe, and we consider possible explanations - instrumental or climatic - for this difference.