Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland
International audience Zachariae Isstrøm (ZI) and Nioghalvfjerdsfjorden (79N) are marine-terminating glaciers in northeast Greenland that hold an ice volume equivalent to a 1.1-m global sea level rise. ZI lost its floating ice shelf, sped up, retreated at 650 m/y, and experienced a 5-gigaton/y mass...
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Online Access: | https://hal.science/hal-03403514 https://hal.science/hal-03403514/document https://hal.science/hal-03403514/file/e2015483118.full.pdf https://doi.org/10.1073/pnas.2015483118 |
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ftunivnantes:oai:HAL:hal-03403514v1 2023-05-15T16:21:27+02:00 Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland An, Lu Rignot, Eric Wood, Michael Willis, Josh Mouginot, Jérémie Khan, Shfaqat University of California Irvine (UC Irvine) University of California (UC) Jet Propulsion Laboratory (JPL) NASA-California Institute of Technology (CALTECH) Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ) Université Grenoble Alpes (UGA) Danmarks Tekniske Universitet = Technical University of Denmark (DTU) 2021 https://hal.science/hal-03403514 https://hal.science/hal-03403514/document https://hal.science/hal-03403514/file/e2015483118.full.pdf https://doi.org/10.1073/pnas.2015483118 en eng HAL CCSD National Academy of Sciences info:eu-repo/semantics/altIdentifier/doi/10.1073/pnas.2015483118 hal-03403514 https://hal.science/hal-03403514 https://hal.science/hal-03403514/document https://hal.science/hal-03403514/file/e2015483118.full.pdf doi:10.1073/pnas.2015483118 info:eu-repo/semantics/OpenAccess ISSN: 0027-8424 EISSN: 1091-6490 Proceedings of the National Academy of Sciences of the United States of America https://hal.science/hal-03403514 Proceedings of the National Academy of Sciences of the United States of America, 2021, 118 (2), pp.e2015483118. ⟨10.1073/pnas.2015483118⟩ Greenland glaciology sea level ice–ocean interaction climate [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2021 ftunivnantes https://doi.org/10.1073/pnas.2015483118 2023-03-01T02:04:08Z International audience Zachariae Isstrøm (ZI) and Nioghalvfjerdsfjorden (79N) are marine-terminating glaciers in northeast Greenland that hold an ice volume equivalent to a 1.1-m global sea level rise. ZI lost its floating ice shelf, sped up, retreated at 650 m/y, and experienced a 5-gigaton/y mass loss. Glacier 79N has been more stable despite its exposure to the same climate forcing. We analyze the impact of ocean thermal forcing on the glaciers. A three-dimensional inversion of airborne gravity data reveals an 800-m-deep, broad channel that allows subsurface, warm, Atlantic Intermediate Water (AIW) (+1. 25 ○ C) to reach the front of ZI via two sills at 350-m depth. Subsurface ocean temperature in that channel has warmed by 1.3 ± 0 . 5 ○ C since 1979. Using an ocean model, we calculate a rate of ice removal at the grounding line by the ocean that increased from 108 m/y to 185 m/y in 1979–2019. Observed ice thinning caused a retreat of its flotation line to increase from 105 m/y to 217 m/y, for a combined grounding line retreat of 13 km in 41 y that matches independent observations within 14%. In contrast, the limited access of AIW to 79N via a narrower passage yields lower grounded ice removal (53 m/y to 99 m/y) and thinning-induced retreat (27 m/y to 50 m/y) for a combined retreat of 4.4 km, also within 12% of observations. Ocean-induced removal of ice at the grounding line, modulated by bathymetric barriers, is therefore a main driver of ice sheet retreat, but it is not incorporated in most ice sheet models. Article in Journal/Newspaper glacier Greenland Ice Sheet Ice Shelf Nioghalvfjerdsfjorden Université de Nantes: HAL-UNIV-NANTES Greenland Nioghalvfjerdsfjorden ENVELOPE(-21.500,-21.500,79.500,79.500) Zachariae Isstrøm ENVELOPE(-21.167,-21.167,78.917,78.917) Proceedings of the National Academy of Sciences 118 2 |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
Greenland glaciology sea level ice–ocean interaction climate [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
Greenland glaciology sea level ice–ocean interaction climate [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography An, Lu Rignot, Eric Wood, Michael Willis, Josh Mouginot, Jérémie Khan, Shfaqat Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland |
topic_facet |
Greenland glaciology sea level ice–ocean interaction climate [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience Zachariae Isstrøm (ZI) and Nioghalvfjerdsfjorden (79N) are marine-terminating glaciers in northeast Greenland that hold an ice volume equivalent to a 1.1-m global sea level rise. ZI lost its floating ice shelf, sped up, retreated at 650 m/y, and experienced a 5-gigaton/y mass loss. Glacier 79N has been more stable despite its exposure to the same climate forcing. We analyze the impact of ocean thermal forcing on the glaciers. A three-dimensional inversion of airborne gravity data reveals an 800-m-deep, broad channel that allows subsurface, warm, Atlantic Intermediate Water (AIW) (+1. 25 ○ C) to reach the front of ZI via two sills at 350-m depth. Subsurface ocean temperature in that channel has warmed by 1.3 ± 0 . 5 ○ C since 1979. Using an ocean model, we calculate a rate of ice removal at the grounding line by the ocean that increased from 108 m/y to 185 m/y in 1979–2019. Observed ice thinning caused a retreat of its flotation line to increase from 105 m/y to 217 m/y, for a combined grounding line retreat of 13 km in 41 y that matches independent observations within 14%. In contrast, the limited access of AIW to 79N via a narrower passage yields lower grounded ice removal (53 m/y to 99 m/y) and thinning-induced retreat (27 m/y to 50 m/y) for a combined retreat of 4.4 km, also within 12% of observations. Ocean-induced removal of ice at the grounding line, modulated by bathymetric barriers, is therefore a main driver of ice sheet retreat, but it is not incorporated in most ice sheet models. |
author2 |
University of California Irvine (UC Irvine) University of California (UC) Jet Propulsion Laboratory (JPL) NASA-California Institute of Technology (CALTECH) Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ) Université Grenoble Alpes (UGA) Danmarks Tekniske Universitet = Technical University of Denmark (DTU) |
format |
Article in Journal/Newspaper |
author |
An, Lu Rignot, Eric Wood, Michael Willis, Josh Mouginot, Jérémie Khan, Shfaqat |
author_facet |
An, Lu Rignot, Eric Wood, Michael Willis, Josh Mouginot, Jérémie Khan, Shfaqat |
author_sort |
An, Lu |
title |
Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland |
title_short |
Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland |
title_full |
Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland |
title_fullStr |
Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland |
title_full_unstemmed |
Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland |
title_sort |
ocean melting of the zachariae isstrøm and nioghalvfjerdsfjorden glaciers, northeast greenland |
publisher |
HAL CCSD |
publishDate |
2021 |
url |
https://hal.science/hal-03403514 https://hal.science/hal-03403514/document https://hal.science/hal-03403514/file/e2015483118.full.pdf https://doi.org/10.1073/pnas.2015483118 |
long_lat |
ENVELOPE(-21.500,-21.500,79.500,79.500) ENVELOPE(-21.167,-21.167,78.917,78.917) |
geographic |
Greenland Nioghalvfjerdsfjorden Zachariae Isstrøm |
geographic_facet |
Greenland Nioghalvfjerdsfjorden Zachariae Isstrøm |
genre |
glacier Greenland Ice Sheet Ice Shelf Nioghalvfjerdsfjorden |
genre_facet |
glacier Greenland Ice Sheet Ice Shelf Nioghalvfjerdsfjorden |
op_source |
ISSN: 0027-8424 EISSN: 1091-6490 Proceedings of the National Academy of Sciences of the United States of America https://hal.science/hal-03403514 Proceedings of the National Academy of Sciences of the United States of America, 2021, 118 (2), pp.e2015483118. ⟨10.1073/pnas.2015483118⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1073/pnas.2015483118 hal-03403514 https://hal.science/hal-03403514 https://hal.science/hal-03403514/document https://hal.science/hal-03403514/file/e2015483118.full.pdf doi:10.1073/pnas.2015483118 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1073/pnas.2015483118 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
118 |
container_issue |
2 |
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1766009460615020544 |