Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland
During summer 2013 we installed a network of 19 GPS nodes at the ungrounded margin of Helheim Glacier in southeast Greenland together with three cameras to study iceberg calving mechanisms. The network collected data at rates up to every 7 s and was designed to be robust to loss of nodes as the glac...
Published in: | Journal of Geophysical Research: Earth Surface |
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Online Access: | https://eprints.whiterose.ac.uk/97232/ https://eprints.whiterose.ac.uk/97232/1/Murray_et_al-2015-Journal_of_Geophysical_Research-_Earth_Surface.pdf https://doi.org/10.1002/2015JF003531 |
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ftleedsuniv:oai:eprints.whiterose.ac.uk:97232 2023-05-15T16:20:56+02:00 Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland Murray, T. Selmes, N. James, T.D. Edwards, S. Martin, I. O'Farrell, T. Aspey, R. Rutt, I. Nettles, M. Bauge, T. 2015-06-01 text https://eprints.whiterose.ac.uk/97232/ https://eprints.whiterose.ac.uk/97232/1/Murray_et_al-2015-Journal_of_Geophysical_Research-_Earth_Surface.pdf https://doi.org/10.1002/2015JF003531 en eng Wiley-Blackwell https://eprints.whiterose.ac.uk/97232/1/Murray_et_al-2015-Journal_of_Geophysical_Research-_Earth_Surface.pdf Murray, T., Selmes, N., James, T.D. et al. (7 more authors) (2015) Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland. Journal of Geophysical Research: Earth Surface, 120 (6). pp. 964-982. ISSN 2169-9003 cc_by_4 CC-BY Article PeerReviewed 2015 ftleedsuniv https://doi.org/10.1002/2015JF003531 2023-01-30T21:40:35Z During summer 2013 we installed a network of 19 GPS nodes at the ungrounded margin of Helheim Glacier in southeast Greenland together with three cameras to study iceberg calving mechanisms. The network collected data at rates up to every 7 s and was designed to be robust to loss of nodes as the glacier calved. Data collection covered 55 days, and many nodes survived in locations right at the glacier front to the time of iceberg calving. The observations included a number of significant calving events, and as a consequence the glacier retreated ~1.5 km. The data provide real-time, high-frequency observations in unprecedented proximity to the calving front. The glacier calved by a process of buoyancy-force-induced crevassing in which the ice downglacier of flexion zones rotates upward because it is out of buoyant equilibrium. Calving then occurs back to the flexion zone. This calving process provides a compelling and complete explanation for the data. Tracking of oblique camera images allows identification and characterisation of the flexion zones and their propagation downglacier. Interpretation of the GPS data and camera data in combination allows us to place constraints on the height of the basal cavity that forms beneath the rotating ice downglacier of the flexion zone before calving. The flexion zones are probably formed by the exploitation of basal crevasses, and theoretical considerations suggest that their propagation is strongly enhanced when the glacier base is deeper than buoyant equilibrium. Thus, this calving mechanism is likely to dominate whenever such geometry occurs and is of increasing importance in Greenland. Article in Journal/Newspaper glacier Greenland White Rose Research Online (Universities of Leeds, Sheffield & York) Greenland Journal of Geophysical Research: Earth Surface 120 6 964 982 |
institution |
Open Polar |
collection |
White Rose Research Online (Universities of Leeds, Sheffield & York) |
op_collection_id |
ftleedsuniv |
language |
English |
description |
During summer 2013 we installed a network of 19 GPS nodes at the ungrounded margin of Helheim Glacier in southeast Greenland together with three cameras to study iceberg calving mechanisms. The network collected data at rates up to every 7 s and was designed to be robust to loss of nodes as the glacier calved. Data collection covered 55 days, and many nodes survived in locations right at the glacier front to the time of iceberg calving. The observations included a number of significant calving events, and as a consequence the glacier retreated ~1.5 km. The data provide real-time, high-frequency observations in unprecedented proximity to the calving front. The glacier calved by a process of buoyancy-force-induced crevassing in which the ice downglacier of flexion zones rotates upward because it is out of buoyant equilibrium. Calving then occurs back to the flexion zone. This calving process provides a compelling and complete explanation for the data. Tracking of oblique camera images allows identification and characterisation of the flexion zones and their propagation downglacier. Interpretation of the GPS data and camera data in combination allows us to place constraints on the height of the basal cavity that forms beneath the rotating ice downglacier of the flexion zone before calving. The flexion zones are probably formed by the exploitation of basal crevasses, and theoretical considerations suggest that their propagation is strongly enhanced when the glacier base is deeper than buoyant equilibrium. Thus, this calving mechanism is likely to dominate whenever such geometry occurs and is of increasing importance in Greenland. |
format |
Article in Journal/Newspaper |
author |
Murray, T. Selmes, N. James, T.D. Edwards, S. Martin, I. O'Farrell, T. Aspey, R. Rutt, I. Nettles, M. Bauge, T. |
spellingShingle |
Murray, T. Selmes, N. James, T.D. Edwards, S. Martin, I. O'Farrell, T. Aspey, R. Rutt, I. Nettles, M. Bauge, T. Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland |
author_facet |
Murray, T. Selmes, N. James, T.D. Edwards, S. Martin, I. O'Farrell, T. Aspey, R. Rutt, I. Nettles, M. Bauge, T. |
author_sort |
Murray, T. |
title |
Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland |
title_short |
Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland |
title_full |
Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland |
title_fullStr |
Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland |
title_full_unstemmed |
Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland |
title_sort |
dynamics of glacier calving at the ungrounded margin of helheim glacier, southeast greenland |
publisher |
Wiley-Blackwell |
publishDate |
2015 |
url |
https://eprints.whiterose.ac.uk/97232/ https://eprints.whiterose.ac.uk/97232/1/Murray_et_al-2015-Journal_of_Geophysical_Research-_Earth_Surface.pdf https://doi.org/10.1002/2015JF003531 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
glacier Greenland |
genre_facet |
glacier Greenland |
op_relation |
https://eprints.whiterose.ac.uk/97232/1/Murray_et_al-2015-Journal_of_Geophysical_Research-_Earth_Surface.pdf Murray, T., Selmes, N., James, T.D. et al. (7 more authors) (2015) Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland. Journal of Geophysical Research: Earth Surface, 120 (6). pp. 964-982. ISSN 2169-9003 |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1002/2015JF003531 |
container_title |
Journal of Geophysical Research: Earth Surface |
container_volume |
120 |
container_issue |
6 |
container_start_page |
964 |
op_container_end_page |
982 |
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1766008955731968000 |