Sensitivity of Heinrich-type ice-sheet surge characteristics to boundary forcing perturbations
Heinrich-type ice-sheet surges are one of the prominent signals of glacial climate variability. They are characterised as abrupt, quasi-periodic episodes of ice-sheet instabilities during which large numbers of icebergs are released from the Laurentide ice sheet. The mechanisms controlling the timin...
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ftdoajarticles:oai:doaj.org/article:92f9b819d5ce448ea24a094b782d752a 2023-05-15T16:39:36+02:00 Sensitivity of Heinrich-type ice-sheet surge characteristics to boundary forcing perturbations C. Schannwell U. Mikolajewicz F. Ziemen M.-L. Kapsch 2023-01-01T00:00:00Z https://doi.org/10.5194/cp-19-179-2023 https://doaj.org/article/92f9b819d5ce448ea24a094b782d752a EN eng Copernicus Publications https://cp.copernicus.org/articles/19/179/2023/cp-19-179-2023.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-19-179-2023 1814-9324 1814-9332 https://doaj.org/article/92f9b819d5ce448ea24a094b782d752a Climate of the Past, Vol 19, Pp 179-198 (2023) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2023 ftdoajarticles https://doi.org/10.5194/cp-19-179-2023 2023-01-29T01:30:35Z Heinrich-type ice-sheet surges are one of the prominent signals of glacial climate variability. They are characterised as abrupt, quasi-periodic episodes of ice-sheet instabilities during which large numbers of icebergs are released from the Laurentide ice sheet. The mechanisms controlling the timing and occurrence of Heinrich-type ice-sheet surges remain poorly constrained to this day. Here, we use a coupled ice sheet–solid Earth model to identify and quantify the importance of boundary forcing for the surge cycle length of Heinrich-type ice-sheet surges for two prominent ice streams of the Laurentide ice sheet – the land-terminating Mackenzie ice stream and the marine-terminating Hudson ice stream. Both ice streams show responses of similar magnitude to surface mass balance and geothermal heat flux perturbations, but Mackenzie ice stream is more sensitive to ice surface temperature perturbations, a fact likely caused by the warmer climate in this region. Ocean and sea-level forcing as well as different frequencies of the same forcing have a negligible effect on the surge cycle length. The simulations also highlight the fact that only a certain parameter space exists under which ice-sheet oscillations can be maintained. Transitioning from an oscillatory state to a persistent ice streaming state can result in an ice volume loss of up to 30 % for the respective ice stream drainage basin under otherwise constant climate conditions. We show that Mackenzie ice stream is susceptible to undergoing such a transition in response to all tested positive climate perturbations. This underlines the potential of the Mackenzie region to have contributed to prominent abrupt climate change events of the last deglaciation. Article in Journal/Newspaper Ice Sheet Directory of Open Access Journals: DOAJ Articles Hudson Climate of the Past 19 1 179 198 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 C. Schannwell U. Mikolajewicz F. Ziemen M.-L. Kapsch Sensitivity of Heinrich-type ice-sheet surge characteristics to boundary forcing perturbations |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
Heinrich-type ice-sheet surges are one of the prominent signals of glacial climate variability. They are characterised as abrupt, quasi-periodic episodes of ice-sheet instabilities during which large numbers of icebergs are released from the Laurentide ice sheet. The mechanisms controlling the timing and occurrence of Heinrich-type ice-sheet surges remain poorly constrained to this day. Here, we use a coupled ice sheet–solid Earth model to identify and quantify the importance of boundary forcing for the surge cycle length of Heinrich-type ice-sheet surges for two prominent ice streams of the Laurentide ice sheet – the land-terminating Mackenzie ice stream and the marine-terminating Hudson ice stream. Both ice streams show responses of similar magnitude to surface mass balance and geothermal heat flux perturbations, but Mackenzie ice stream is more sensitive to ice surface temperature perturbations, a fact likely caused by the warmer climate in this region. Ocean and sea-level forcing as well as different frequencies of the same forcing have a negligible effect on the surge cycle length. The simulations also highlight the fact that only a certain parameter space exists under which ice-sheet oscillations can be maintained. Transitioning from an oscillatory state to a persistent ice streaming state can result in an ice volume loss of up to 30 % for the respective ice stream drainage basin under otherwise constant climate conditions. We show that Mackenzie ice stream is susceptible to undergoing such a transition in response to all tested positive climate perturbations. This underlines the potential of the Mackenzie region to have contributed to prominent abrupt climate change events of the last deglaciation. |
format |
Article in Journal/Newspaper |
author |
C. Schannwell U. Mikolajewicz F. Ziemen M.-L. Kapsch |
author_facet |
C. Schannwell U. Mikolajewicz F. Ziemen M.-L. Kapsch |
author_sort |
C. Schannwell |
title |
Sensitivity of Heinrich-type ice-sheet surge characteristics to boundary forcing perturbations |
title_short |
Sensitivity of Heinrich-type ice-sheet surge characteristics to boundary forcing perturbations |
title_full |
Sensitivity of Heinrich-type ice-sheet surge characteristics to boundary forcing perturbations |
title_fullStr |
Sensitivity of Heinrich-type ice-sheet surge characteristics to boundary forcing perturbations |
title_full_unstemmed |
Sensitivity of Heinrich-type ice-sheet surge characteristics to boundary forcing perturbations |
title_sort |
sensitivity of heinrich-type ice-sheet surge characteristics to boundary forcing perturbations |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/cp-19-179-2023 https://doaj.org/article/92f9b819d5ce448ea24a094b782d752a |
geographic |
Hudson |
geographic_facet |
Hudson |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Climate of the Past, Vol 19, Pp 179-198 (2023) |
op_relation |
https://cp.copernicus.org/articles/19/179/2023/cp-19-179-2023.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-19-179-2023 1814-9324 1814-9332 https://doaj.org/article/92f9b819d5ce448ea24a094b782d752a |
op_doi |
https://doi.org/10.5194/cp-19-179-2023 |
container_title |
Climate of the Past |
container_volume |
19 |
container_issue |
1 |
container_start_page |
179 |
op_container_end_page |
198 |
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1766029933809762304 |