Glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt
Mass loss from glaciers and ice sheets currently accounts for two-thirds of the observed global sea-level rise and has accelerated since the 1990s, coincident with strong atmospheric warming in the polar regions. Here we present continuous GPS measurements and satellite synthetic-aperture-radar-base...
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ftdoajarticles:oai:doaj.org/article:b9db90db649046478e06504d81296b8e 2023-05-15T15:33:56+02:00 Glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt T. Dunse T. Schellenberger J. O. Hagen A. Kääb T. V. Schuler C. H. Reijmer 2015-02-01T00:00:00Z https://doi.org/10.5194/tc-9-197-2015 https://doaj.org/article/b9db90db649046478e06504d81296b8e EN eng Copernicus Publications http://www.the-cryosphere.net/9/197/2015/tc-9-197-2015.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-9-197-2015 https://doaj.org/article/b9db90db649046478e06504d81296b8e The Cryosphere, Vol 9, Iss 1, Pp 197-215 (2015) Environmental sciences GE1-350 Geology QE1-996.5 article 2015 ftdoajarticles https://doi.org/10.5194/tc-9-197-2015 2022-12-31T01:17:22Z Mass loss from glaciers and ice sheets currently accounts for two-thirds of the observed global sea-level rise and has accelerated since the 1990s, coincident with strong atmospheric warming in the polar regions. Here we present continuous GPS measurements and satellite synthetic-aperture-radar-based velocity maps from Basin-3, the largest drainage basin of the Austfonna ice cap, Svalbard. Our observations demonstrate strong links between surface-melt and multiannual ice-flow acceleration. We identify a hydro-thermodynamic feedback that successively mobilizes stagnant ice regions, initially frozen to their bed, thereby facilitating fast basal motion over an expanding area. By autumn 2012, successive destabilization of the marine terminus escalated in a surge of Basin-3. The resulting iceberg discharge of 4.2±1.6 Gt a −1 over the period April 2012 to May 2013 triples the calving loss from the entire ice cap. With the seawater displacement by the terminus advance accounted for, the related sea-level rise contribution amounts to 7.2±2.6 Gt a −1 . This rate matches the annual ice-mass loss from the entire Svalbard archipelago over the period 2003–2008, highlighting the importance of dynamic mass loss for glacier mass balance and sea-level rise. The active role of surface melt, i.e. external forcing, contrasts with previous views of glacier surges as purely internal dynamic instabilities. Given sustained climatic warming and rising significance of surface melt, we propose a potential impact of the hydro-thermodynamic feedback on the future stability of ice-sheet regions, namely at the presence of a cold-based marginal ice plug that restricts fast drainage of inland ice. The possibility of large-scale dynamic instabilities such as the partial disintegration of ice sheets is acknowledged but not quantified in global projections of sea-level rise. Article in Journal/Newspaper Austfonna glacier Ice cap Ice Sheet Svalbard The Cryosphere Directory of Open Access Journals: DOAJ Articles Austfonna ENVELOPE(24.559,24.559,79.835,79.835) Svalbard Svalbard Archipelago The Cryosphere 9 1 197 215 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 T. Dunse T. Schellenberger J. O. Hagen A. Kääb T. V. Schuler C. H. Reijmer Glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Mass loss from glaciers and ice sheets currently accounts for two-thirds of the observed global sea-level rise and has accelerated since the 1990s, coincident with strong atmospheric warming in the polar regions. Here we present continuous GPS measurements and satellite synthetic-aperture-radar-based velocity maps from Basin-3, the largest drainage basin of the Austfonna ice cap, Svalbard. Our observations demonstrate strong links between surface-melt and multiannual ice-flow acceleration. We identify a hydro-thermodynamic feedback that successively mobilizes stagnant ice regions, initially frozen to their bed, thereby facilitating fast basal motion over an expanding area. By autumn 2012, successive destabilization of the marine terminus escalated in a surge of Basin-3. The resulting iceberg discharge of 4.2±1.6 Gt a −1 over the period April 2012 to May 2013 triples the calving loss from the entire ice cap. With the seawater displacement by the terminus advance accounted for, the related sea-level rise contribution amounts to 7.2±2.6 Gt a −1 . This rate matches the annual ice-mass loss from the entire Svalbard archipelago over the period 2003–2008, highlighting the importance of dynamic mass loss for glacier mass balance and sea-level rise. The active role of surface melt, i.e. external forcing, contrasts with previous views of glacier surges as purely internal dynamic instabilities. Given sustained climatic warming and rising significance of surface melt, we propose a potential impact of the hydro-thermodynamic feedback on the future stability of ice-sheet regions, namely at the presence of a cold-based marginal ice plug that restricts fast drainage of inland ice. The possibility of large-scale dynamic instabilities such as the partial disintegration of ice sheets is acknowledged but not quantified in global projections of sea-level rise. |
format |
Article in Journal/Newspaper |
author |
T. Dunse T. Schellenberger J. O. Hagen A. Kääb T. V. Schuler C. H. Reijmer |
author_facet |
T. Dunse T. Schellenberger J. O. Hagen A. Kääb T. V. Schuler C. H. Reijmer |
author_sort |
T. Dunse |
title |
Glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt |
title_short |
Glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt |
title_full |
Glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt |
title_fullStr |
Glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt |
title_full_unstemmed |
Glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt |
title_sort |
glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt |
publisher |
Copernicus Publications |
publishDate |
2015 |
url |
https://doi.org/10.5194/tc-9-197-2015 https://doaj.org/article/b9db90db649046478e06504d81296b8e |
long_lat |
ENVELOPE(24.559,24.559,79.835,79.835) |
geographic |
Austfonna Svalbard Svalbard Archipelago |
geographic_facet |
Austfonna Svalbard Svalbard Archipelago |
genre |
Austfonna glacier Ice cap Ice Sheet Svalbard The Cryosphere |
genre_facet |
Austfonna glacier Ice cap Ice Sheet Svalbard The Cryosphere |
op_source |
The Cryosphere, Vol 9, Iss 1, Pp 197-215 (2015) |
op_relation |
http://www.the-cryosphere.net/9/197/2015/tc-9-197-2015.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-9-197-2015 https://doaj.org/article/b9db90db649046478e06504d81296b8e |
op_doi |
https://doi.org/10.5194/tc-9-197-2015 |
container_title |
The Cryosphere |
container_volume |
9 |
container_issue |
1 |
container_start_page |
197 |
op_container_end_page |
215 |
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1766364521225519104 |