Elevation bias due to penetration of spaceborne radar signal on Grosser Aletschgletscher, Switzerland
Digital elevation models (DEMs) from the spaceborne interferometric radar mission TanDEM-X hold a large potential for glacier change assessments. However, a bias is potentially introduced through the penetration of the X-band signal into snow and firn. To improve our understanding of radar penetrati...
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Cambridge University Press
2024-01-01
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| Series: | Journal of Glaciology |
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| Online Access: | https://www.cambridge.org/core/product/identifier/S0022143024000376/type/journal_article |
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| author | Jacqueline Bannwart Livia Piermattei Inés Dussaillant Lukas Krieger Dana Floricioiu Etienne Berthier Claudia Roeoesli Horst Machguth Michael Zemp |
| author_facet | Jacqueline Bannwart Livia Piermattei Inés Dussaillant Lukas Krieger Dana Floricioiu Etienne Berthier Claudia Roeoesli Horst Machguth Michael Zemp |
| author_sort | Jacqueline Bannwart |
| collection | DOAJ |
| description | Digital elevation models (DEMs) from the spaceborne interferometric radar mission TanDEM-X hold a large potential for glacier change assessments. However, a bias is potentially introduced through the penetration of the X-band signal into snow and firn. To improve our understanding of radar penetration on glaciers, we compare DEMs derived from the almost synchronous acquisition of TanDEM-X and Pléiades optical stereo-images of Grosser Aletschgletscher in March 2021. We found that the elevation bias – averaged per elevation bin – can reach up to 4–8 m in the accumulation area, depending on post co-registration corrections. Concurrent in situ measurements (ground-penetrating radar, snow cores, snow pits) reveal that the signal is not obstructed by the last summer horizon but reaches into perennial firn. Because of volume scattering, the TanDEM-X surface is determined by the scattering phase centre and does not coincide with a specific firn layer. We show that the bias corresponds to more than half of the decadal ice loss rate. To minimize the radar penetration bias, we recommend to select DEMs from the same time of the year and over long observation periods. A correction of the radar penetration bias is recommended, especially when combining optical and TanDEM-X DEMs. |
| format | Article |
| id | doaj-art-309859ed43294dccb98828d00c451233 |
| institution | Kabale University |
| issn | 0022-1430 1727-5652 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | Cambridge University Press |
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| series | Journal of Glaciology |
| spelling | doaj-art-309859ed43294dccb98828d00c4512332025-01-16T21:51:22ZengCambridge University PressJournal of Glaciology0022-14301727-56522024-01-017010.1017/jog.2024.37Elevation bias due to penetration of spaceborne radar signal on Grosser Aletschgletscher, SwitzerlandJacqueline Bannwart0https://orcid.org/0000-0001-7136-0685Livia Piermattei1https://orcid.org/0000-0003-2814-8659Inés Dussaillant2https://orcid.org/0000-0003-0617-7731Lukas Krieger3https://orcid.org/0000-0002-2464-3102Dana Floricioiu4https://orcid.org/0000-0002-1647-7191Etienne Berthier5https://orcid.org/0000-0001-5978-9155Claudia Roeoesli6https://orcid.org/0000-0003-4656-7080Horst Machguth7https://orcid.org/0000-0001-5924-0998Michael Zemp8https://orcid.org/0000-0003-2391-7877Department of Geography, University of Zurich, Zurich, SwitzerlandDepartment of Geography, University of Zurich, Zurich, Switzerland Department of Geosciences, University of Oslo, Oslo, NorwayDepartment of Geography, University of Zurich, Zurich, SwitzerlandRemote Sensing Technology Institute, DLR, Oberpfaffenhofen, Wessling, GermanyRemote Sensing Technology Institute, DLR, Oberpfaffenhofen, Wessling, GermanyUniversité de Toulouse, LEGOS (CNES/CNRS/IRD/UT3), Toulouse, FranceDepartment of Geography, University of Zurich, Zurich, SwitzerlandDepartment of Geoscience, University of Fribourg, Fribourg, SwitzerlandDepartment of Geography, University of Zurich, Zurich, SwitzerlandDigital elevation models (DEMs) from the spaceborne interferometric radar mission TanDEM-X hold a large potential for glacier change assessments. However, a bias is potentially introduced through the penetration of the X-band signal into snow and firn. To improve our understanding of radar penetration on glaciers, we compare DEMs derived from the almost synchronous acquisition of TanDEM-X and Pléiades optical stereo-images of Grosser Aletschgletscher in March 2021. We found that the elevation bias – averaged per elevation bin – can reach up to 4–8 m in the accumulation area, depending on post co-registration corrections. Concurrent in situ measurements (ground-penetrating radar, snow cores, snow pits) reveal that the signal is not obstructed by the last summer horizon but reaches into perennial firn. Because of volume scattering, the TanDEM-X surface is determined by the scattering phase centre and does not coincide with a specific firn layer. We show that the bias corresponds to more than half of the decadal ice loss rate. To minimize the radar penetration bias, we recommend to select DEMs from the same time of the year and over long observation periods. A correction of the radar penetration bias is recommended, especially when combining optical and TanDEM-X DEMs.https://www.cambridge.org/core/product/identifier/S0022143024000376/type/journal_articleGlacier mass balanceground-penetrating radarremote sensing |
| spellingShingle | Jacqueline Bannwart Livia Piermattei Inés Dussaillant Lukas Krieger Dana Floricioiu Etienne Berthier Claudia Roeoesli Horst Machguth Michael Zemp Elevation bias due to penetration of spaceborne radar signal on Grosser Aletschgletscher, Switzerland Journal of Glaciology Glacier mass balance ground-penetrating radar remote sensing |
| title | Elevation bias due to penetration of spaceborne radar signal on Grosser Aletschgletscher, Switzerland |
| title_full | Elevation bias due to penetration of spaceborne radar signal on Grosser Aletschgletscher, Switzerland |
| title_fullStr | Elevation bias due to penetration of spaceborne radar signal on Grosser Aletschgletscher, Switzerland |
| title_full_unstemmed | Elevation bias due to penetration of spaceborne radar signal on Grosser Aletschgletscher, Switzerland |
| title_short | Elevation bias due to penetration of spaceborne radar signal on Grosser Aletschgletscher, Switzerland |
| title_sort | elevation bias due to penetration of spaceborne radar signal on grosser aletschgletscher switzerland |
| topic | Glacier mass balance ground-penetrating radar remote sensing |
| url | https://www.cambridge.org/core/product/identifier/S0022143024000376/type/journal_article |
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