Paleo-ice sheet reconstructions constrained by GIA and geological data for use in climate models
Paleo-ice sheet reconstructions are complicated by large uncertainties, particularly since it is usually only possible to infer thickness from indirect means such as the response of glacial isostatic adjustment (GIA). GIA itself has large uncertainties with respect to the rheological structure of th...
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ftawi:oai:epic.awi.de:46684 2023-05-15T16:39:39+02:00 Paleo-ice sheet reconstructions constrained by GIA and geological data for use in climate models Gowan, Evan Zhang, Xu Khosravi, Sara Lohmann, Gerrit Grosfeld, Klaus 2017-09 application/pdf https://epic.awi.de/id/eprint/46684/ https://epic.awi.de/id/eprint/46684/1/pmip_poster.pdf https://hdl.handle.net/10013/epic.a9ea3b15-04f2-418d-bbb8-4766f23a1d19 https://hdl.handle.net/ unknown https://epic.awi.de/id/eprint/46684/1/pmip_poster.pdf https://hdl.handle.net/ Gowan, E. orcid:0000-0002-0119-9440 , Zhang, X. orcid:0000-0003-1833-9689 , Khosravi, S. , Lohmann, G. orcid:0000-0003-2089-733X and Grosfeld, K. orcid:0000-0001-5936-179X (2017) Paleo-ice sheet reconstructions constrained by GIA and geological data for use in climate models , 1st PMIP4 Conference, Stockholm, Sweden, 25 September 2017 - 29 September 2017 . hdl:10013/epic.a9ea3b15-04f2-418d-bbb8-4766f23a1d19 EPIC31st PMIP4 Conference, Stockholm, Sweden, 2017-09-25-2017-09-29 Conference notRev 2017 ftawi 2021-12-24T15:43:41Z Paleo-ice sheet reconstructions are complicated by large uncertainties, particularly since it is usually only possible to infer thickness from indirect means such as the response of glacial isostatic adjustment (GIA). GIA itself has large uncertainties with respect to the rheological structure of the Earth, and it is possible to get multiple possible best fitting ice sheet configurations using different Earth models. Usually the best geological constraints for paleo-ice sheets are ice margin location, via dating methods and geomorphological features. Using the program ICESHEET (Gowan et al 2016), it is possible to exploit this knowledge and create glaciologically consistent ice sheet reconstructions for use in GIA modeling. We demonstrate this by applying them to the North American Laurentide and Innuitian ice sheets, and show that it is possible to have an ice sheet that has a much lower profile than other GIA constrained reconstructions such as ICE-6G, GLAC-1 and ANU. A lower profile ice sheet has profound implications for past climate reconstructions, including radically different atmospheric and Atlantic Ocean circulation at the Last Glacial Maximum. Such a reconstruction is better able to fit geological constraints in the near field, but are at odds with global sea level reconstructions that require much larger ice volume. We discuss possible solutions to this issue. Another benefit of ICESHEET is that it does not require climatic information, since the ice thickness is adjusted by changing a spatially and temporarily variable basal shear stress parameter. Using these reconstructions in climate models do not face the circularity of dynamic ice sheet models that require a climatic input that was often derived from a-priori ice sheet reconstructions. Conference Object Ice Sheet Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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Paleo-ice sheet reconstructions are complicated by large uncertainties, particularly since it is usually only possible to infer thickness from indirect means such as the response of glacial isostatic adjustment (GIA). GIA itself has large uncertainties with respect to the rheological structure of the Earth, and it is possible to get multiple possible best fitting ice sheet configurations using different Earth models. Usually the best geological constraints for paleo-ice sheets are ice margin location, via dating methods and geomorphological features. Using the program ICESHEET (Gowan et al 2016), it is possible to exploit this knowledge and create glaciologically consistent ice sheet reconstructions for use in GIA modeling. We demonstrate this by applying them to the North American Laurentide and Innuitian ice sheets, and show that it is possible to have an ice sheet that has a much lower profile than other GIA constrained reconstructions such as ICE-6G, GLAC-1 and ANU. A lower profile ice sheet has profound implications for past climate reconstructions, including radically different atmospheric and Atlantic Ocean circulation at the Last Glacial Maximum. Such a reconstruction is better able to fit geological constraints in the near field, but are at odds with global sea level reconstructions that require much larger ice volume. We discuss possible solutions to this issue. Another benefit of ICESHEET is that it does not require climatic information, since the ice thickness is adjusted by changing a spatially and temporarily variable basal shear stress parameter. Using these reconstructions in climate models do not face the circularity of dynamic ice sheet models that require a climatic input that was often derived from a-priori ice sheet reconstructions. |
format |
Conference Object |
author |
Gowan, Evan Zhang, Xu Khosravi, Sara Lohmann, Gerrit Grosfeld, Klaus |
spellingShingle |
Gowan, Evan Zhang, Xu Khosravi, Sara Lohmann, Gerrit Grosfeld, Klaus Paleo-ice sheet reconstructions constrained by GIA and geological data for use in climate models |
author_facet |
Gowan, Evan Zhang, Xu Khosravi, Sara Lohmann, Gerrit Grosfeld, Klaus |
author_sort |
Gowan, Evan |
title |
Paleo-ice sheet reconstructions constrained by GIA and geological data for use in climate models |
title_short |
Paleo-ice sheet reconstructions constrained by GIA and geological data for use in climate models |
title_full |
Paleo-ice sheet reconstructions constrained by GIA and geological data for use in climate models |
title_fullStr |
Paleo-ice sheet reconstructions constrained by GIA and geological data for use in climate models |
title_full_unstemmed |
Paleo-ice sheet reconstructions constrained by GIA and geological data for use in climate models |
title_sort |
paleo-ice sheet reconstructions constrained by gia and geological data for use in climate models |
publishDate |
2017 |
url |
https://epic.awi.de/id/eprint/46684/ https://epic.awi.de/id/eprint/46684/1/pmip_poster.pdf https://hdl.handle.net/10013/epic.a9ea3b15-04f2-418d-bbb8-4766f23a1d19 https://hdl.handle.net/ |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
EPIC31st PMIP4 Conference, Stockholm, Sweden, 2017-09-25-2017-09-29 |
op_relation |
https://epic.awi.de/id/eprint/46684/1/pmip_poster.pdf https://hdl.handle.net/ Gowan, E. orcid:0000-0002-0119-9440 , Zhang, X. orcid:0000-0003-1833-9689 , Khosravi, S. , Lohmann, G. orcid:0000-0003-2089-733X and Grosfeld, K. orcid:0000-0001-5936-179X (2017) Paleo-ice sheet reconstructions constrained by GIA and geological data for use in climate models , 1st PMIP4 Conference, Stockholm, Sweden, 25 September 2017 - 29 September 2017 . hdl:10013/epic.a9ea3b15-04f2-418d-bbb8-4766f23a1d19 |
_version_ |
1766029978489585664 |