The role of the atmosphere on Northern Hemisphere ice sheet evolution during the late Pleistocene
During the late Pleistocene, the Northern Hemisphere ice sheets waxed and waned with a periodicity of around 100 kyr. They are among the largest topographic features that can amplify, pace or drive global climate change on different time scales. Studying ice sheet-climate feedback through numerical...
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Universität Bremen
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Online Access: | https://media.suub.uni-bremen.de/handle/elib/1738 https://nbn-resolving.org/urn:nbn:de:gbv:46-00108568-17 |
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ftsubbremen:oai:media.suub.uni-bremen.de:Publications/elib/1738 2023-05-15T16:00:00+02:00 The role of the atmosphere on Northern Hemisphere ice sheet evolution during the late Pleistocene Die Rolle der Atmosphäre bei der Entwicklung der Eisschilde der nördlichen Hemisphäre im späten Pleistozän Niu, Lu Lohmann, Gerrit Schulz, Michael 2019-12-20 application/pdf https://media.suub.uni-bremen.de/handle/elib/1738 https://nbn-resolving.org/urn:nbn:de:gbv:46-00108568-17 eng eng Universität Bremen FB1 Physik/Elektrotechnik https://media.suub.uni-bremen.de/handle/elib/1738 urn:nbn:de:gbv:46-00108568-17 info:eu-repo/semantics/openAccess Northern Hemisphere ice sheets Ice sheet modelling Coupled climate-ice sheet modelling The glacial-interglacial cycles Dansgaard-Oeschger events Marine Isotope Stage 13 500 500 Science ddc:500 Dissertation doctoralThesis 2019 ftsubbremen 2022-11-09T07:09:40Z During the late Pleistocene, the Northern Hemisphere ice sheets waxed and waned with a periodicity of around 100 kyr. They are among the largest topographic features that can amplify, pace or drive global climate change on different time scales. Studying ice sheet-climate feedback through numerical modelling is necessary for understanding the physical mechanisms of the Earth system. As mainly land-based ice sheets, the role of the atmosphere on Northern Hemisphere ice sheet evolution during the late Pleistocene is investigated. The evolution of Northern Hemisphere ice sheets through the last glacial cycle is simulated with the glacial index method by using the climate forcing from a general circulation model, COSMOS. By comparing the simulated results to geological reconstructions, we first show that the modelled climate is capable of capturing the main features of the ice-sheet evolution. However, large deviations exist, likely due to the absence of nonlinear interactions between ice sheet and other climate components. The model uncertainties of the climate forcing are examined using the output from nine climate models from the Paleoclimate Modelling Intercomparison Project Phase III. The results show a large variability in simulated ice sheets between the different models. We find that the ice sheet extent pattern resembles summer surface air temperature pattern at the Last Glacial Maximum, confirming the dominant role of surface ablation process for high-latitude Northern Hemisphere ice sheets. This study shows the importance of the upper boundary condition for ice sheet modelling, and implies that careful constraints on climate output is essential for simulating realistic glacial Northern Hemisphere ice sheets. Evidence from proxy records indicates that millenniala scale abrupt climate shifts, called Dansgaard-Oeschger events, happened during past glacial cycles. We show that the Dansgaard-Oeschger events can regulate the mean state of the Northern Hemisphere ice sheets. Sensitivity experiments show that the ... Doctoral or Postdoctoral Thesis Dansgaard-Oeschger events Eisschild* Ice Sheet Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) |
institution |
Open Polar |
collection |
Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) |
op_collection_id |
ftsubbremen |
language |
English |
topic |
Northern Hemisphere ice sheets Ice sheet modelling Coupled climate-ice sheet modelling The glacial-interglacial cycles Dansgaard-Oeschger events Marine Isotope Stage 13 500 500 Science ddc:500 |
spellingShingle |
Northern Hemisphere ice sheets Ice sheet modelling Coupled climate-ice sheet modelling The glacial-interglacial cycles Dansgaard-Oeschger events Marine Isotope Stage 13 500 500 Science ddc:500 Niu, Lu The role of the atmosphere on Northern Hemisphere ice sheet evolution during the late Pleistocene |
topic_facet |
Northern Hemisphere ice sheets Ice sheet modelling Coupled climate-ice sheet modelling The glacial-interglacial cycles Dansgaard-Oeschger events Marine Isotope Stage 13 500 500 Science ddc:500 |
description |
During the late Pleistocene, the Northern Hemisphere ice sheets waxed and waned with a periodicity of around 100 kyr. They are among the largest topographic features that can amplify, pace or drive global climate change on different time scales. Studying ice sheet-climate feedback through numerical modelling is necessary for understanding the physical mechanisms of the Earth system. As mainly land-based ice sheets, the role of the atmosphere on Northern Hemisphere ice sheet evolution during the late Pleistocene is investigated. The evolution of Northern Hemisphere ice sheets through the last glacial cycle is simulated with the glacial index method by using the climate forcing from a general circulation model, COSMOS. By comparing the simulated results to geological reconstructions, we first show that the modelled climate is capable of capturing the main features of the ice-sheet evolution. However, large deviations exist, likely due to the absence of nonlinear interactions between ice sheet and other climate components. The model uncertainties of the climate forcing are examined using the output from nine climate models from the Paleoclimate Modelling Intercomparison Project Phase III. The results show a large variability in simulated ice sheets between the different models. We find that the ice sheet extent pattern resembles summer surface air temperature pattern at the Last Glacial Maximum, confirming the dominant role of surface ablation process for high-latitude Northern Hemisphere ice sheets. This study shows the importance of the upper boundary condition for ice sheet modelling, and implies that careful constraints on climate output is essential for simulating realistic glacial Northern Hemisphere ice sheets. Evidence from proxy records indicates that millenniala scale abrupt climate shifts, called Dansgaard-Oeschger events, happened during past glacial cycles. We show that the Dansgaard-Oeschger events can regulate the mean state of the Northern Hemisphere ice sheets. Sensitivity experiments show that the ... |
author2 |
Lohmann, Gerrit Schulz, Michael |
format |
Doctoral or Postdoctoral Thesis |
author |
Niu, Lu |
author_facet |
Niu, Lu |
author_sort |
Niu, Lu |
title |
The role of the atmosphere on Northern Hemisphere ice sheet evolution during the late Pleistocene |
title_short |
The role of the atmosphere on Northern Hemisphere ice sheet evolution during the late Pleistocene |
title_full |
The role of the atmosphere on Northern Hemisphere ice sheet evolution during the late Pleistocene |
title_fullStr |
The role of the atmosphere on Northern Hemisphere ice sheet evolution during the late Pleistocene |
title_full_unstemmed |
The role of the atmosphere on Northern Hemisphere ice sheet evolution during the late Pleistocene |
title_sort |
role of the atmosphere on northern hemisphere ice sheet evolution during the late pleistocene |
publisher |
Universität Bremen |
publishDate |
2019 |
url |
https://media.suub.uni-bremen.de/handle/elib/1738 https://nbn-resolving.org/urn:nbn:de:gbv:46-00108568-17 |
genre |
Dansgaard-Oeschger events Eisschild* Ice Sheet |
genre_facet |
Dansgaard-Oeschger events Eisschild* Ice Sheet |
op_relation |
https://media.suub.uni-bremen.de/handle/elib/1738 urn:nbn:de:gbv:46-00108568-17 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766395872384385024 |