Interpretation of radio echo sounding in polar ice sheets
Experimental results are presented from a traverse over the ice sheet of north western Greenland in 1964, during which a continuously recorded profile of ice thickness was obtained for the first time. Interpretation of data from this traverse is consistent with results of subsequent work to December...
Published in: | Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences |
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Format: | Article in Journal/Newspaper |
Language: | English |
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1969
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Online Access: | http://dx.doi.org/10.1098/rsta.1969.0063 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1969.0063 |
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crroyalsociety:10.1098/rsta.1969.0063 2024-09-15T17:44:10+00:00 Interpretation of radio echo sounding in polar ice sheets 1969 http://dx.doi.org/10.1098/rsta.1969.0063 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1969.0063 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences volume 265, issue 1166, page 437-505 ISSN 0080-4614 2054-0272 journal-article 1969 crroyalsociety https://doi.org/10.1098/rsta.1969.0063 2024-08-19T04:24:54Z Experimental results are presented from a traverse over the ice sheet of north western Greenland in 1964, during which a continuously recorded profile of ice thickness was obtained for the first time. Interpretation of data from this traverse is consistent with results of subsequent work to December 1967. The parameters of the apparatus are presented briefly, while the details of electronic circuits are being published separately. Theoretical problems of radio wave propagation in an ice sheet and, in particular, the factors affecting accuracy are discussed. The uncertainty in depth, over a small area, is ±5 m ±1.5% and this is verified by comparison with the seismic results for a range of depths up to 1.5 km. It is found that the only real uncertainty arises in irregular terrain. The effectiveness of the radio echo technique is dependent on the absorption of radio waves in ice. Temperature, and to a lesser extent the impurity content of ice, appear to be the main variables affecting field performance. Earlier laboratory results on the variation of absorption with temperature for ice cores from northwest Greenland, together with theoretically predicted temperature distributions throughout the ice mass, have provided estimates of the total loss by absorption. These estimates are reasonably consistent with the observed echo strengths over most of the traverse. Consequently, it is predicted that echoes can be obtained over considerable areas of the ice sheets of Greenland and Antarctica, as has been verified by subsequent observations. The reflexion coefficient at the ice/rock interface is of the order of —15 dB. It could rise to 0 dB for an ice/water interface and one area was found in Greenland where it appeared to fall to — 30 dB. Results from this traverse have shown that local surface slopes on the ice sheet are largely controlled by variations of longitudinal stress along the line of flow. Regional slopes over several kilometres vary with the velocity of movement of the ice, but appear to be less dependent on ... Article in Journal/Newspaper Antarc* Antarctica Greenland Ice Sheet The Royal Society Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences 265 1166 437 505 |
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Open Polar |
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The Royal Society |
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crroyalsociety |
language |
English |
description |
Experimental results are presented from a traverse over the ice sheet of north western Greenland in 1964, during which a continuously recorded profile of ice thickness was obtained for the first time. Interpretation of data from this traverse is consistent with results of subsequent work to December 1967. The parameters of the apparatus are presented briefly, while the details of electronic circuits are being published separately. Theoretical problems of radio wave propagation in an ice sheet and, in particular, the factors affecting accuracy are discussed. The uncertainty in depth, over a small area, is ±5 m ±1.5% and this is verified by comparison with the seismic results for a range of depths up to 1.5 km. It is found that the only real uncertainty arises in irregular terrain. The effectiveness of the radio echo technique is dependent on the absorption of radio waves in ice. Temperature, and to a lesser extent the impurity content of ice, appear to be the main variables affecting field performance. Earlier laboratory results on the variation of absorption with temperature for ice cores from northwest Greenland, together with theoretically predicted temperature distributions throughout the ice mass, have provided estimates of the total loss by absorption. These estimates are reasonably consistent with the observed echo strengths over most of the traverse. Consequently, it is predicted that echoes can be obtained over considerable areas of the ice sheets of Greenland and Antarctica, as has been verified by subsequent observations. The reflexion coefficient at the ice/rock interface is of the order of —15 dB. It could rise to 0 dB for an ice/water interface and one area was found in Greenland where it appeared to fall to — 30 dB. Results from this traverse have shown that local surface slopes on the ice sheet are largely controlled by variations of longitudinal stress along the line of flow. Regional slopes over several kilometres vary with the velocity of movement of the ice, but appear to be less dependent on ... |
format |
Article in Journal/Newspaper |
title |
Interpretation of radio echo sounding in polar ice sheets |
spellingShingle |
Interpretation of radio echo sounding in polar ice sheets |
title_short |
Interpretation of radio echo sounding in polar ice sheets |
title_full |
Interpretation of radio echo sounding in polar ice sheets |
title_fullStr |
Interpretation of radio echo sounding in polar ice sheets |
title_full_unstemmed |
Interpretation of radio echo sounding in polar ice sheets |
title_sort |
interpretation of radio echo sounding in polar ice sheets |
publisher |
The Royal Society |
publishDate |
1969 |
url |
http://dx.doi.org/10.1098/rsta.1969.0063 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1969.0063 |
genre |
Antarc* Antarctica Greenland Ice Sheet |
genre_facet |
Antarc* Antarctica Greenland Ice Sheet |
op_source |
Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences volume 265, issue 1166, page 437-505 ISSN 0080-4614 2054-0272 |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rsta.1969.0063 |
container_title |
Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences |
container_volume |
265 |
container_issue |
1166 |
container_start_page |
437 |
op_container_end_page |
505 |
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1810491553941028864 |