On the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach
Simulation approaches to firn densification often rely on the assumption that grain boundary sliding is the leading process driving the first stage of densification. Alley (1987) first developed a process-based material model of firn that describes this process. However, often so-called semi-empiric...
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ftawi:oai:epic.awi.de:55489 2023-05-15T13:45:22+02:00 On the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach Schultz, Timm Müller, Ralf Gross, Dietmar Humbert, Angelika 2022-01-14 application/pdf https://epic.awi.de/id/eprint/55489/ https://epic.awi.de/id/eprint/55489/1/tc-16-143-2022.pdf https://tc.copernicus.org/articles/16/143/2022/tc-16-143-2022.html https://hdl.handle.net/10013/epic.e5c343e9-4df6-41ed-8dc5-2cf20ceb05db https://hdl.handle.net/ unknown https://epic.awi.de/id/eprint/55489/1/tc-16-143-2022.pdf https://hdl.handle.net/ Schultz, T. , Müller, R. , Gross, D. and Humbert, A. orcid:0000-0002-0244-8760 (2022) On the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach , The Cryosphere, 16 , pp. 143-158 . doi:10.5194/tc-16-143-2022 <https://doi.org/10.5194/tc-16-143-2022> , hdl:10013/epic.e5c343e9-4df6-41ed-8dc5-2cf20ceb05db EPIC3The Cryosphere, 16, pp. 143-158 Article isiRev 2022 ftawi https://doi.org/10.5194/tc-16-143-2022 2022-01-24T00:09:59Z Simulation approaches to firn densification often rely on the assumption that grain boundary sliding is the leading process driving the first stage of densification. Alley (1987) first developed a process-based material model of firn that describes this process. However, often so-called semi-empirical models are favored over the physical description of grain boundary sliding owing to their simplicity and the uncertainties regarding model parameters. In this study, we assessed the applicability of the grain boundary sliding model of Alley (1987) to firn using a numeric firn densification model and an optimization approach, for which we formulated variants of the constitutive relation of Alley (1987). An efficient model implementation based on an updated Lagrangian numerical scheme enabled us to perform a large number of simulations to test different model parameters and identify the simulation results that best reproduced 159 firn density profiles from Greenland and Antarctica. For most of the investigated locations, the simulated and measured firn density profiles were in good agreement. This result implies that the constitutive relation of Alley (1987) characterizes the first stage of firn densification well when suitable model parameters are used. An analysis of the parameters that result in the best agreement revealed a dependence on the mean surface mass balance. This finding may indicate that the load is insufficiently described, as the lateral components of the stress tensor are usually neglected in one-dimensional models of the firn column. Article in Journal/Newspaper Antarc* Antarctica Greenland The Cryosphere Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Greenland The Cryosphere 16 1 143 158 |
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Open Polar |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
Simulation approaches to firn densification often rely on the assumption that grain boundary sliding is the leading process driving the first stage of densification. Alley (1987) first developed a process-based material model of firn that describes this process. However, often so-called semi-empirical models are favored over the physical description of grain boundary sliding owing to their simplicity and the uncertainties regarding model parameters. In this study, we assessed the applicability of the grain boundary sliding model of Alley (1987) to firn using a numeric firn densification model and an optimization approach, for which we formulated variants of the constitutive relation of Alley (1987). An efficient model implementation based on an updated Lagrangian numerical scheme enabled us to perform a large number of simulations to test different model parameters and identify the simulation results that best reproduced 159 firn density profiles from Greenland and Antarctica. For most of the investigated locations, the simulated and measured firn density profiles were in good agreement. This result implies that the constitutive relation of Alley (1987) characterizes the first stage of firn densification well when suitable model parameters are used. An analysis of the parameters that result in the best agreement revealed a dependence on the mean surface mass balance. This finding may indicate that the load is insufficiently described, as the lateral components of the stress tensor are usually neglected in one-dimensional models of the firn column. |
format |
Article in Journal/Newspaper |
author |
Schultz, Timm Müller, Ralf Gross, Dietmar Humbert, Angelika |
spellingShingle |
Schultz, Timm Müller, Ralf Gross, Dietmar Humbert, Angelika On the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach |
author_facet |
Schultz, Timm Müller, Ralf Gross, Dietmar Humbert, Angelika |
author_sort |
Schultz, Timm |
title |
On the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach |
title_short |
On the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach |
title_full |
On the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach |
title_fullStr |
On the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach |
title_full_unstemmed |
On the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach |
title_sort |
on the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach |
publishDate |
2022 |
url |
https://epic.awi.de/id/eprint/55489/ https://epic.awi.de/id/eprint/55489/1/tc-16-143-2022.pdf https://tc.copernicus.org/articles/16/143/2022/tc-16-143-2022.html https://hdl.handle.net/10013/epic.e5c343e9-4df6-41ed-8dc5-2cf20ceb05db https://hdl.handle.net/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Antarc* Antarctica Greenland The Cryosphere |
genre_facet |
Antarc* Antarctica Greenland The Cryosphere |
op_source |
EPIC3The Cryosphere, 16, pp. 143-158 |
op_relation |
https://epic.awi.de/id/eprint/55489/1/tc-16-143-2022.pdf https://hdl.handle.net/ Schultz, T. , Müller, R. , Gross, D. and Humbert, A. orcid:0000-0002-0244-8760 (2022) On the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach , The Cryosphere, 16 , pp. 143-158 . doi:10.5194/tc-16-143-2022 <https://doi.org/10.5194/tc-16-143-2022> , hdl:10013/epic.e5c343e9-4df6-41ed-8dc5-2cf20ceb05db |
op_doi |
https://doi.org/10.5194/tc-16-143-2022 |
container_title |
The Cryosphere |
container_volume |
16 |
container_issue |
1 |
container_start_page |
143 |
op_container_end_page |
158 |
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1766222714022920192 |