Coupled Northern Hemisphere permafrost-ice-sheet evolution over the last glacial cycle
Permafrost influences a number of processes which are relevant for local and global climate. For example, it is well known that permafrost plays an important role in global carbon and methane cycles. Less is known about the interaction between permafrost and ice sheets. In this study a permafrost mo...
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fttibhannoverren:oai:oa.tib.eu:123456789/639 2024-09-15T17:52:13+00:00 Coupled Northern Hemisphere permafrost-ice-sheet evolution over the last glacial cycle Willeit, M. Ganopolski, A. 2015 application/pdf https://oa.tib.eu/renate/handle/123456789/639 https://doi.org/10.34657/864 eng eng München : European Geopyhsical Union DOI:https://doi.org/10.5194/cp-11-1165-2015 https://doi.org/10.34657/864 https://oa.tib.eu/renate/handle/123456789/639 CC BY 3.0 Unported https://creativecommons.org/licenses/by/3.0/ frei zugänglich ddc:550 biogeochemical cycle geothermal energy global climate heat fluxice sheet Last Glacial Maximum Northern Hemisphere paleoclimate performance assessment permafrost sedimentary sequence surface temperature thermal conductivity status-type:publishedVersion doc-type:Article doc-type:Text 2015 fttibhannoverren https://doi.org/10.34657/86410.5194/cp-11-1165-2015 2024-06-26T23:32:42Z Permafrost influences a number of processes which are relevant for local and global climate. For example, it is well known that permafrost plays an important role in global carbon and methane cycles. Less is known about the interaction between permafrost and ice sheets. In this study a permafrost module is included in the Earth system model CLIMBER-2, and the coupled Northern Hemisphere (NH) permafrost–ice-sheet evolution over the last glacial cycle is explored. The model performs generally well at reproducing present-day permafrost extent and thickness. Modeled permafrost thickness is sensitive to the values of ground porosity, thermal conductivity and geothermal heat flux. Permafrost extent at the Last Glacial Maximum (LGM) agrees well with reconstructions and previous modeling estimates. Present-day permafrost thickness is far from equilibrium over deep permafrost regions. Over central Siberia and the Arctic Archipelago permafrost is presently up to 200–500 m thicker than it would be at equilibrium. In these areas, present-day permafrost depth strongly depends on the past climate history and simulations indicate that deep permafrost has a memory of surface temperature variations going back to at least 800 ka. Over the last glacial cycle permafrost has a relatively modest impact on simulated NH ice sheet volume except at LGM, when including permafrost increases ice volume by about 15 m sea level equivalent in our model. This is explained by a delayed melting of the ice base from below by the geothermal heat flux when the ice sheet sits on a porous sediment layer and permafrost has to be melted first. Permafrost affects ice sheet dynamics only when ice extends over areas covered by thick sediments, which is the case at LGM. Article in Journal/Newspaper Arctic Archipelago Ice Ice Sheet permafrost Siberia Renate - Repositorium für Naturwissenschaften und Technik (TIB Hannover) |
institution |
Open Polar |
collection |
Renate - Repositorium für Naturwissenschaften und Technik (TIB Hannover) |
op_collection_id |
fttibhannoverren |
language |
English |
topic |
ddc:550 biogeochemical cycle geothermal energy global climate heat fluxice sheet Last Glacial Maximum Northern Hemisphere paleoclimate performance assessment permafrost sedimentary sequence surface temperature thermal conductivity |
spellingShingle |
ddc:550 biogeochemical cycle geothermal energy global climate heat fluxice sheet Last Glacial Maximum Northern Hemisphere paleoclimate performance assessment permafrost sedimentary sequence surface temperature thermal conductivity Willeit, M. Ganopolski, A. Coupled Northern Hemisphere permafrost-ice-sheet evolution over the last glacial cycle |
topic_facet |
ddc:550 biogeochemical cycle geothermal energy global climate heat fluxice sheet Last Glacial Maximum Northern Hemisphere paleoclimate performance assessment permafrost sedimentary sequence surface temperature thermal conductivity |
description |
Permafrost influences a number of processes which are relevant for local and global climate. For example, it is well known that permafrost plays an important role in global carbon and methane cycles. Less is known about the interaction between permafrost and ice sheets. In this study a permafrost module is included in the Earth system model CLIMBER-2, and the coupled Northern Hemisphere (NH) permafrost–ice-sheet evolution over the last glacial cycle is explored. The model performs generally well at reproducing present-day permafrost extent and thickness. Modeled permafrost thickness is sensitive to the values of ground porosity, thermal conductivity and geothermal heat flux. Permafrost extent at the Last Glacial Maximum (LGM) agrees well with reconstructions and previous modeling estimates. Present-day permafrost thickness is far from equilibrium over deep permafrost regions. Over central Siberia and the Arctic Archipelago permafrost is presently up to 200–500 m thicker than it would be at equilibrium. In these areas, present-day permafrost depth strongly depends on the past climate history and simulations indicate that deep permafrost has a memory of surface temperature variations going back to at least 800 ka. Over the last glacial cycle permafrost has a relatively modest impact on simulated NH ice sheet volume except at LGM, when including permafrost increases ice volume by about 15 m sea level equivalent in our model. This is explained by a delayed melting of the ice base from below by the geothermal heat flux when the ice sheet sits on a porous sediment layer and permafrost has to be melted first. Permafrost affects ice sheet dynamics only when ice extends over areas covered by thick sediments, which is the case at LGM. |
format |
Article in Journal/Newspaper |
author |
Willeit, M. Ganopolski, A. |
author_facet |
Willeit, M. Ganopolski, A. |
author_sort |
Willeit, M. |
title |
Coupled Northern Hemisphere permafrost-ice-sheet evolution over the last glacial cycle |
title_short |
Coupled Northern Hemisphere permafrost-ice-sheet evolution over the last glacial cycle |
title_full |
Coupled Northern Hemisphere permafrost-ice-sheet evolution over the last glacial cycle |
title_fullStr |
Coupled Northern Hemisphere permafrost-ice-sheet evolution over the last glacial cycle |
title_full_unstemmed |
Coupled Northern Hemisphere permafrost-ice-sheet evolution over the last glacial cycle |
title_sort |
coupled northern hemisphere permafrost-ice-sheet evolution over the last glacial cycle |
publisher |
München : European Geopyhsical Union |
publishDate |
2015 |
url |
https://oa.tib.eu/renate/handle/123456789/639 https://doi.org/10.34657/864 |
genre |
Arctic Archipelago Ice Ice Sheet permafrost Siberia |
genre_facet |
Arctic Archipelago Ice Ice Sheet permafrost Siberia |
op_relation |
DOI:https://doi.org/10.5194/cp-11-1165-2015 https://doi.org/10.34657/864 https://oa.tib.eu/renate/handle/123456789/639 |
op_rights |
CC BY 3.0 Unported https://creativecommons.org/licenses/by/3.0/ frei zugänglich |
op_doi |
https://doi.org/10.34657/86410.5194/cp-11-1165-2015 |
_version_ |
1810294289906794496 |