Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS
The Northeast Greenland Ice Stream (NEGIS) extends around 600 km upstream from the coast to its onset near the ice divide in interior Greenland. Several maps of surface velocity and topography of interior Greenland exist, but their accuracy is not well constrained by in situ observations. Here we pr...
Published in: | The Cryosphere |
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2020
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Online Access: | https://orbit.dtu.dk/en/publications/e94cbee1-670f-47af-8ec2-03de5a7d2551 https://doi.org/10.5194/tc-14-3487-2020 https://backend.orbit.dtu.dk/ws/files/234022215/tc_14_3487_2020.pdf |
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ftdtupubl:oai:pure.atira.dk:publications/e94cbee1-670f-47af-8ec2-03de5a7d2551 2024-09-15T18:04:21+00:00 Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS Hvidberg, Christine S. Grinsted, Aslak Dahl-Jensen, Dorthe Khan, Shfaqat Abbas Kusk, Anders Andersen, Jonas Kvist Neckel, Niklas Solgaard, Anne Karlsson, Nanna B. Kjar, Helle Astrid Vallelonga, Paul 2020 application/pdf https://orbit.dtu.dk/en/publications/e94cbee1-670f-47af-8ec2-03de5a7d2551 https://doi.org/10.5194/tc-14-3487-2020 https://backend.orbit.dtu.dk/ws/files/234022215/tc_14_3487_2020.pdf eng eng https://orbit.dtu.dk/en/publications/e94cbee1-670f-47af-8ec2-03de5a7d2551 info:eu-repo/semantics/openAccess Hvidberg , C S , Grinsted , A , Dahl-Jensen , D , Khan , S A , Kusk , A , Andersen , J K , Neckel , N , Solgaard , A , Karlsson , N B , Kjar , H A & Vallelonga , P 2020 , ' Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS ' , Cryosphere , vol. 14 , no. 10 , pp. 3487-3502 . https://doi.org/10.5194/tc-14-3487-2020 article 2020 ftdtupubl https://doi.org/10.5194/tc-14-3487-2020 2024-08-13T00:03:06Z The Northeast Greenland Ice Stream (NEGIS) extends around 600 km upstream from the coast to its onset near the ice divide in interior Greenland. Several maps of surface velocity and topography of interior Greenland exist, but their accuracy is not well constrained by in situ observations. Here we present the results from a GPS mapping of surface velocity in an area located approximately 150 km from the ice divide near the East Greenland Ice-core Project (EastGRIP) deep-drilling site. A GPS strain net consisting of 63 poles was established and observed over the years 2015-2019. The strain net covers an area of 35 km by 40 km, including both shear margins. The ice flows with a uniform surface speed of approximately 55ma1 within a central flow band with longitudinal and transverse strain rates on the order of 104 a1 and increasing by an order of magnitude in the shear margins. We compare the GPS results to the Arctic Digital Elevation Model and a list of satellite-derived surface velocity products in order to evaluate these products. For each velocity product, we determine the bias in and precision of the velocity compared to the GPS observations, as well as the smoothing of the velocity products needed to obtain optimal precision. The best products have a bias and a precision of 0:5ma1. We combine the GPS results with satellite-derived products and show that organized patterns in flow and topography emerge in NEGIS when the surface velocity exceeds approximately 55ma1 and are related to bedrock topography. Article in Journal/Newspaper East Greenland East Greenland Ice-core Project Greenland Greenland ice core Greenland Ice core Project ice core Technical University of Denmark: DTU Orbit The Cryosphere 14 10 3487 3502 |
institution |
Open Polar |
collection |
Technical University of Denmark: DTU Orbit |
op_collection_id |
ftdtupubl |
language |
English |
description |
The Northeast Greenland Ice Stream (NEGIS) extends around 600 km upstream from the coast to its onset near the ice divide in interior Greenland. Several maps of surface velocity and topography of interior Greenland exist, but their accuracy is not well constrained by in situ observations. Here we present the results from a GPS mapping of surface velocity in an area located approximately 150 km from the ice divide near the East Greenland Ice-core Project (EastGRIP) deep-drilling site. A GPS strain net consisting of 63 poles was established and observed over the years 2015-2019. The strain net covers an area of 35 km by 40 km, including both shear margins. The ice flows with a uniform surface speed of approximately 55ma1 within a central flow band with longitudinal and transverse strain rates on the order of 104 a1 and increasing by an order of magnitude in the shear margins. We compare the GPS results to the Arctic Digital Elevation Model and a list of satellite-derived surface velocity products in order to evaluate these products. For each velocity product, we determine the bias in and precision of the velocity compared to the GPS observations, as well as the smoothing of the velocity products needed to obtain optimal precision. The best products have a bias and a precision of 0:5ma1. We combine the GPS results with satellite-derived products and show that organized patterns in flow and topography emerge in NEGIS when the surface velocity exceeds approximately 55ma1 and are related to bedrock topography. |
format |
Article in Journal/Newspaper |
author |
Hvidberg, Christine S. Grinsted, Aslak Dahl-Jensen, Dorthe Khan, Shfaqat Abbas Kusk, Anders Andersen, Jonas Kvist Neckel, Niklas Solgaard, Anne Karlsson, Nanna B. Kjar, Helle Astrid Vallelonga, Paul |
spellingShingle |
Hvidberg, Christine S. Grinsted, Aslak Dahl-Jensen, Dorthe Khan, Shfaqat Abbas Kusk, Anders Andersen, Jonas Kvist Neckel, Niklas Solgaard, Anne Karlsson, Nanna B. Kjar, Helle Astrid Vallelonga, Paul Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS |
author_facet |
Hvidberg, Christine S. Grinsted, Aslak Dahl-Jensen, Dorthe Khan, Shfaqat Abbas Kusk, Anders Andersen, Jonas Kvist Neckel, Niklas Solgaard, Anne Karlsson, Nanna B. Kjar, Helle Astrid Vallelonga, Paul |
author_sort |
Hvidberg, Christine S. |
title |
Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS |
title_short |
Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS |
title_full |
Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS |
title_fullStr |
Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS |
title_full_unstemmed |
Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS |
title_sort |
surface velocity of the northeast greenland ice stream (negis): assessment of interior velocities derived from satellite data by gps |
publishDate |
2020 |
url |
https://orbit.dtu.dk/en/publications/e94cbee1-670f-47af-8ec2-03de5a7d2551 https://doi.org/10.5194/tc-14-3487-2020 https://backend.orbit.dtu.dk/ws/files/234022215/tc_14_3487_2020.pdf |
genre |
East Greenland East Greenland Ice-core Project Greenland Greenland ice core Greenland Ice core Project ice core |
genre_facet |
East Greenland East Greenland Ice-core Project Greenland Greenland ice core Greenland Ice core Project ice core |
op_source |
Hvidberg , C S , Grinsted , A , Dahl-Jensen , D , Khan , S A , Kusk , A , Andersen , J K , Neckel , N , Solgaard , A , Karlsson , N B , Kjar , H A & Vallelonga , P 2020 , ' Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS ' , Cryosphere , vol. 14 , no. 10 , pp. 3487-3502 . https://doi.org/10.5194/tc-14-3487-2020 |
op_relation |
https://orbit.dtu.dk/en/publications/e94cbee1-670f-47af-8ec2-03de5a7d2551 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-14-3487-2020 |
container_title |
The Cryosphere |
container_volume |
14 |
container_issue |
10 |
container_start_page |
3487 |
op_container_end_page |
3502 |
_version_ |
1810441841507565568 |