Geospatial simulations of airborne ice-penetrating radar surveying reveal elevation under-measurement bias for ice-sheet bed topography
Airborne radio-echo sounding (RES) surveys are widely used to measure ice-sheet bed topography. Measuring bed topography as accurately and widely as possible is of critical importance to modelling ice dynamics and hence to constraining better future ice response to climate change. Measurement accura...
Published in: | Annals of Glaciology |
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Cambridge University Press
2020
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Online Access: | https://doi.org/10.1017/aog.2020.35 https://doaj.org/article/429e3d0e634345638764827fdf8398be |
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ftdoajarticles:oai:doaj.org/article:429e3d0e634345638764827fdf8398be 2023-05-15T13:29:29+02:00 Geospatial simulations of airborne ice-penetrating radar surveying reveal elevation under-measurement bias for ice-sheet bed topography Oliver T. Bartlett Steven J. Palmer Dustin M. Schroeder Emma J. MacKie Timothy T. Barrows Alastair G. C. Graham 2020-04-01T00:00:00Z https://doi.org/10.1017/aog.2020.35 https://doaj.org/article/429e3d0e634345638764827fdf8398be EN eng Cambridge University Press https://www.cambridge.org/core/product/identifier/S026030552000035X/type/journal_article https://doaj.org/toc/0260-3055 https://doaj.org/toc/1727-5644 doi:10.1017/aog.2020.35 0260-3055 1727-5644 https://doaj.org/article/429e3d0e634345638764827fdf8398be Annals of Glaciology, Vol 61, Pp 46-57 (2020) Glaciological instruments and methods Greenland Ice Sheet radio-echo sounding subglacial topography Meteorology. Climatology QC851-999 article 2020 ftdoajarticles https://doi.org/10.1017/aog.2020.35 2023-03-12T01:31:55Z Airborne radio-echo sounding (RES) surveys are widely used to measure ice-sheet bed topography. Measuring bed topography as accurately and widely as possible is of critical importance to modelling ice dynamics and hence to constraining better future ice response to climate change. Measurement accuracy of RES surveys is influenced both by the geometry of bed topography and the survey design. Here we develop a novel approach for simulating RES surveys over glaciated terrain, to quantify the sensitivity of derived bed elevation to topographic geometry. Furthermore, we investigate how measurement errors influence the quantification of glacial valley geometry. We find a negative bias across RES measurements, where off-nadir return measurement error is typically −1.8 ± 11.6 m. Topographic highlands are under-measured an order of magnitude more than lowlands. Consequently, valley depth and cross-sectional area are largely under-estimated. While overall estimates of ice thickness are likely too high, we find large glacier valley cross-sectional area to be under-estimated by −2.8 ± 18.1%. Therefore, estimates of ice flux through large outlet glaciers are likely too low when this effect is not taken into account. Additionally, bed mismeasurements potentially impact our appreciation of outlet-glacier stability. Article in Journal/Newspaper Annals of Glaciology glacier Greenland Ice Sheet Directory of Open Access Journals: DOAJ Articles Greenland Annals of Glaciology 61 81 46 57 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Glaciological instruments and methods Greenland Ice Sheet radio-echo sounding subglacial topography Meteorology. Climatology QC851-999 |
spellingShingle |
Glaciological instruments and methods Greenland Ice Sheet radio-echo sounding subglacial topography Meteorology. Climatology QC851-999 Oliver T. Bartlett Steven J. Palmer Dustin M. Schroeder Emma J. MacKie Timothy T. Barrows Alastair G. C. Graham Geospatial simulations of airborne ice-penetrating radar surveying reveal elevation under-measurement bias for ice-sheet bed topography |
topic_facet |
Glaciological instruments and methods Greenland Ice Sheet radio-echo sounding subglacial topography Meteorology. Climatology QC851-999 |
description |
Airborne radio-echo sounding (RES) surveys are widely used to measure ice-sheet bed topography. Measuring bed topography as accurately and widely as possible is of critical importance to modelling ice dynamics and hence to constraining better future ice response to climate change. Measurement accuracy of RES surveys is influenced both by the geometry of bed topography and the survey design. Here we develop a novel approach for simulating RES surveys over glaciated terrain, to quantify the sensitivity of derived bed elevation to topographic geometry. Furthermore, we investigate how measurement errors influence the quantification of glacial valley geometry. We find a negative bias across RES measurements, where off-nadir return measurement error is typically −1.8 ± 11.6 m. Topographic highlands are under-measured an order of magnitude more than lowlands. Consequently, valley depth and cross-sectional area are largely under-estimated. While overall estimates of ice thickness are likely too high, we find large glacier valley cross-sectional area to be under-estimated by −2.8 ± 18.1%. Therefore, estimates of ice flux through large outlet glaciers are likely too low when this effect is not taken into account. Additionally, bed mismeasurements potentially impact our appreciation of outlet-glacier stability. |
format |
Article in Journal/Newspaper |
author |
Oliver T. Bartlett Steven J. Palmer Dustin M. Schroeder Emma J. MacKie Timothy T. Barrows Alastair G. C. Graham |
author_facet |
Oliver T. Bartlett Steven J. Palmer Dustin M. Schroeder Emma J. MacKie Timothy T. Barrows Alastair G. C. Graham |
author_sort |
Oliver T. Bartlett |
title |
Geospatial simulations of airborne ice-penetrating radar surveying reveal elevation under-measurement bias for ice-sheet bed topography |
title_short |
Geospatial simulations of airborne ice-penetrating radar surveying reveal elevation under-measurement bias for ice-sheet bed topography |
title_full |
Geospatial simulations of airborne ice-penetrating radar surveying reveal elevation under-measurement bias for ice-sheet bed topography |
title_fullStr |
Geospatial simulations of airborne ice-penetrating radar surveying reveal elevation under-measurement bias for ice-sheet bed topography |
title_full_unstemmed |
Geospatial simulations of airborne ice-penetrating radar surveying reveal elevation under-measurement bias for ice-sheet bed topography |
title_sort |
geospatial simulations of airborne ice-penetrating radar surveying reveal elevation under-measurement bias for ice-sheet bed topography |
publisher |
Cambridge University Press |
publishDate |
2020 |
url |
https://doi.org/10.1017/aog.2020.35 https://doaj.org/article/429e3d0e634345638764827fdf8398be |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Annals of Glaciology glacier Greenland Ice Sheet |
genre_facet |
Annals of Glaciology glacier Greenland Ice Sheet |
op_source |
Annals of Glaciology, Vol 61, Pp 46-57 (2020) |
op_relation |
https://www.cambridge.org/core/product/identifier/S026030552000035X/type/journal_article https://doaj.org/toc/0260-3055 https://doaj.org/toc/1727-5644 doi:10.1017/aog.2020.35 0260-3055 1727-5644 https://doaj.org/article/429e3d0e634345638764827fdf8398be |
op_doi |
https://doi.org/10.1017/aog.2020.35 |
container_title |
Annals of Glaciology |
container_volume |
61 |
container_issue |
81 |
container_start_page |
46 |
op_container_end_page |
57 |
_version_ |
1766000926484594688 |