Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland
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 b...
Published in: | Proceedings of the National Academy of Sciences |
---|---|
Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2021
|
Subjects: | |
Online Access: | https://orbit.dtu.dk/en/publications/c2cd2f5d-3477-401f-b52e-5fd2e63245e4 https://doi.org/10.1073/pnas.2015483118 https://backend.orbit.dtu.dk/ws/files/237842297/e2015483118.full.pdf |
id |
ftdtupubl:oai:pure.atira.dk:publications/c2cd2f5d-3477-401f-b52e-5fd2e63245e4 |
---|---|
record_format |
openpolar |
spelling |
ftdtupubl:oai:pure.atira.dk:publications/c2cd2f5d-3477-401f-b52e-5fd2e63245e4 2024-06-23T07:53:02+00:00 Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland An, Lu Rignot, Eric Wood, Michael Willis, Josh K. Mouginot, Jérémie Khan, Shfaqat A. 2021 application/pdf https://orbit.dtu.dk/en/publications/c2cd2f5d-3477-401f-b52e-5fd2e63245e4 https://doi.org/10.1073/pnas.2015483118 https://backend.orbit.dtu.dk/ws/files/237842297/e2015483118.full.pdf eng eng https://orbit.dtu.dk/en/publications/c2cd2f5d-3477-401f-b52e-5fd2e63245e4 info:eu-repo/semantics/openAccess An , L , Rignot , E , Wood , M , Willis , J K , Mouginot , J & Khan , S A 2021 , ' Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland ' , Proceedings of the National Academy of Sciences of the United States of America , vol. 118 , no. 2 , e2015483118 . https://doi.org/10.1073/pnas.2015483118 /dk/atira/pure/sustainabledevelopmentgoals/climate_action name=SDG 13 - Climate Action /dk/atira/pure/sustainabledevelopmentgoals/life_below_water name=SDG 14 - Life Below Water article 2021 ftdtupubl https://doi.org/10.1073/pnas.2015483118 2024-06-11T14:58:58Z 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.[Formula: see text]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[Formula: see text]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 Technical University of Denmark: DTU Orbit 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 e2015483118 |
institution |
Open Polar |
collection |
Technical University of Denmark: DTU Orbit |
op_collection_id |
ftdtupubl |
language |
English |
topic |
/dk/atira/pure/sustainabledevelopmentgoals/climate_action name=SDG 13 - Climate Action /dk/atira/pure/sustainabledevelopmentgoals/life_below_water name=SDG 14 - Life Below Water |
spellingShingle |
/dk/atira/pure/sustainabledevelopmentgoals/climate_action name=SDG 13 - Climate Action /dk/atira/pure/sustainabledevelopmentgoals/life_below_water name=SDG 14 - Life Below Water An, Lu Rignot, Eric Wood, Michael Willis, Josh K. Mouginot, Jérémie Khan, Shfaqat A. Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland |
topic_facet |
/dk/atira/pure/sustainabledevelopmentgoals/climate_action name=SDG 13 - Climate Action /dk/atira/pure/sustainabledevelopmentgoals/life_below_water name=SDG 14 - Life Below Water |
description |
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.[Formula: see text]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[Formula: see text]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. |
format |
Article in Journal/Newspaper |
author |
An, Lu Rignot, Eric Wood, Michael Willis, Josh K. Mouginot, Jérémie Khan, Shfaqat A. |
author_facet |
An, Lu Rignot, Eric Wood, Michael Willis, Josh K. Mouginot, Jérémie Khan, Shfaqat A. |
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 |
publishDate |
2021 |
url |
https://orbit.dtu.dk/en/publications/c2cd2f5d-3477-401f-b52e-5fd2e63245e4 https://doi.org/10.1073/pnas.2015483118 https://backend.orbit.dtu.dk/ws/files/237842297/e2015483118.full.pdf |
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 |
An , L , Rignot , E , Wood , M , Willis , J K , Mouginot , J & Khan , S A 2021 , ' Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland ' , Proceedings of the National Academy of Sciences of the United States of America , vol. 118 , no. 2 , e2015483118 . https://doi.org/10.1073/pnas.2015483118 |
op_relation |
https://orbit.dtu.dk/en/publications/c2cd2f5d-3477-401f-b52e-5fd2e63245e4 |
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 |
container_start_page |
e2015483118 |
_version_ |
1802644514105458688 |