Net effect of ice-sheet–atmosphere interactions reduces simulated transient Miocene Antarctic ice-sheet variability
Benthic δ 18 O levels vary strongly during the warmer-than-modern early and mid-Miocene (23 to 14 Myr ago), suggesting a dynamic Antarctic ice sheet (AIS). So far, however, realistic simulations of the Miocene AIS have been limited to equilibrium states under different CO 2 levels and orbital settin...
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Online Access: | https://doi.org/10.5194/tc-16-1315-2022 https://doaj.org/article/95cbf6ae5cae42c48b912c3ee60a48ed |
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ftdoajarticles:oai:doaj.org/article:95cbf6ae5cae42c48b912c3ee60a48ed 2023-05-15T13:49:31+02:00 Net effect of ice-sheet–atmosphere interactions reduces simulated transient Miocene Antarctic ice-sheet variability L. B. Stap C. J. Berends M. D. W. Scherrenberg R. S. W. van de Wal E. G. W. Gasson 2022-04-01T00:00:00Z https://doi.org/10.5194/tc-16-1315-2022 https://doaj.org/article/95cbf6ae5cae42c48b912c3ee60a48ed EN eng Copernicus Publications https://tc.copernicus.org/articles/16/1315/2022/tc-16-1315-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-1315-2022 1994-0416 1994-0424 https://doaj.org/article/95cbf6ae5cae42c48b912c3ee60a48ed The Cryosphere, Vol 16, Pp 1315-1332 (2022) Environmental sciences GE1-350 Geology QE1-996.5 article 2022 ftdoajarticles https://doi.org/10.5194/tc-16-1315-2022 2022-12-31T11:42:01Z Benthic δ 18 O levels vary strongly during the warmer-than-modern early and mid-Miocene (23 to 14 Myr ago), suggesting a dynamic Antarctic ice sheet (AIS). So far, however, realistic simulations of the Miocene AIS have been limited to equilibrium states under different CO 2 levels and orbital settings. Earlier transient simulations lacked ice-sheet–atmosphere interactions and used a present-day rather than Miocene Antarctic bedrock topography. Here, we quantify the effect of ice-sheet–atmosphere interactions, running the ice-sheet model IMAU-ICE using climate forcing from Miocene simulations by the general circulation model GENESIS. Utilising a recently developed matrix interpolation method enables us to interpolate the climate forcing based on CO 2 levels (between 280 and 840 ppm), as well as varying ice-sheet configurations (between no ice and a large East Antarctic Ice Sheet). We furthermore implement recent reconstructions of Miocene Antarctic bedrock topography. We find that the positive albedo–temperature feedback, partly compensated for by a negative feedback between ice volume and precipitation, increases hysteresis in the relation between CO 2 and ice volume. Together, these ice-sheet–atmosphere interactions decrease the amplitude of Miocene AIS variability in idealised transient simulations. Forced by quasi-orbital 40 kyr forcing CO 2 cycles, the ice volume variability reduces by 21 % when ice-sheet–atmosphere interactions are included compared to when forcing variability is only based on CO 2 changes. Thereby, these interactions also diminish the contribution of AIS variability to benthic δ 18 O fluctuations. Evolving bedrock topography during the early and mid-Miocene also reduces ice volume variability by 10 % under equal 40 kyr cycles of atmosphere and ocean forcing. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet The Cryosphere Directory of Open Access Journals: DOAJ Articles Antarctic East Antarctic Ice Sheet The Cryosphere 16 4 1315 1332 |
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 L. B. Stap C. J. Berends M. D. W. Scherrenberg R. S. W. van de Wal E. G. W. Gasson Net effect of ice-sheet–atmosphere interactions reduces simulated transient Miocene Antarctic ice-sheet variability |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Benthic δ 18 O levels vary strongly during the warmer-than-modern early and mid-Miocene (23 to 14 Myr ago), suggesting a dynamic Antarctic ice sheet (AIS). So far, however, realistic simulations of the Miocene AIS have been limited to equilibrium states under different CO 2 levels and orbital settings. Earlier transient simulations lacked ice-sheet–atmosphere interactions and used a present-day rather than Miocene Antarctic bedrock topography. Here, we quantify the effect of ice-sheet–atmosphere interactions, running the ice-sheet model IMAU-ICE using climate forcing from Miocene simulations by the general circulation model GENESIS. Utilising a recently developed matrix interpolation method enables us to interpolate the climate forcing based on CO 2 levels (between 280 and 840 ppm), as well as varying ice-sheet configurations (between no ice and a large East Antarctic Ice Sheet). We furthermore implement recent reconstructions of Miocene Antarctic bedrock topography. We find that the positive albedo–temperature feedback, partly compensated for by a negative feedback between ice volume and precipitation, increases hysteresis in the relation between CO 2 and ice volume. Together, these ice-sheet–atmosphere interactions decrease the amplitude of Miocene AIS variability in idealised transient simulations. Forced by quasi-orbital 40 kyr forcing CO 2 cycles, the ice volume variability reduces by 21 % when ice-sheet–atmosphere interactions are included compared to when forcing variability is only based on CO 2 changes. Thereby, these interactions also diminish the contribution of AIS variability to benthic δ 18 O fluctuations. Evolving bedrock topography during the early and mid-Miocene also reduces ice volume variability by 10 % under equal 40 kyr cycles of atmosphere and ocean forcing. |
format |
Article in Journal/Newspaper |
author |
L. B. Stap C. J. Berends M. D. W. Scherrenberg R. S. W. van de Wal E. G. W. Gasson |
author_facet |
L. B. Stap C. J. Berends M. D. W. Scherrenberg R. S. W. van de Wal E. G. W. Gasson |
author_sort |
L. B. Stap |
title |
Net effect of ice-sheet–atmosphere interactions reduces simulated transient Miocene Antarctic ice-sheet variability |
title_short |
Net effect of ice-sheet–atmosphere interactions reduces simulated transient Miocene Antarctic ice-sheet variability |
title_full |
Net effect of ice-sheet–atmosphere interactions reduces simulated transient Miocene Antarctic ice-sheet variability |
title_fullStr |
Net effect of ice-sheet–atmosphere interactions reduces simulated transient Miocene Antarctic ice-sheet variability |
title_full_unstemmed |
Net effect of ice-sheet–atmosphere interactions reduces simulated transient Miocene Antarctic ice-sheet variability |
title_sort |
net effect of ice-sheet–atmosphere interactions reduces simulated transient miocene antarctic ice-sheet variability |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-16-1315-2022 https://doaj.org/article/95cbf6ae5cae42c48b912c3ee60a48ed |
geographic |
Antarctic East Antarctic Ice Sheet |
geographic_facet |
Antarctic East Antarctic Ice Sheet |
genre |
Antarc* Antarctic Ice Sheet The Cryosphere |
genre_facet |
Antarc* Antarctic Ice Sheet The Cryosphere |
op_source |
The Cryosphere, Vol 16, Pp 1315-1332 (2022) |
op_relation |
https://tc.copernicus.org/articles/16/1315/2022/tc-16-1315-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-1315-2022 1994-0416 1994-0424 https://doaj.org/article/95cbf6ae5cae42c48b912c3ee60a48ed |
op_doi |
https://doi.org/10.5194/tc-16-1315-2022 |
container_title |
The Cryosphere |
container_volume |
16 |
container_issue |
4 |
container_start_page |
1315 |
op_container_end_page |
1332 |
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1766251464778317824 |