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-empir...
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ftdoajarticles:oai:doaj.org/article:0b0592384c3e419aa496d65d5eb7c114 2023-05-15T13:36:56+02:00 On the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach T. Schultz R. Müller D. Gross A. Humbert 2022-01-01T00:00:00Z https://doi.org/10.5194/tc-16-143-2022 https://doaj.org/article/0b0592384c3e419aa496d65d5eb7c114 EN eng Copernicus Publications https://tc.copernicus.org/articles/16/143/2022/tc-16-143-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-143-2022 1994-0416 1994-0424 https://doaj.org/article/0b0592384c3e419aa496d65d5eb7c114 The Cryosphere, Vol 16, Pp 143-158 (2022) Environmental sciences GE1-350 Geology QE1-996.5 article 2022 ftdoajarticles https://doi.org/10.5194/tc-16-143-2022 2022-12-31T10:39:46Z 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 Directory of Open Access Journals: DOAJ Articles Greenland The Cryosphere 16 1 143 158 |
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 T. Schultz R. Müller D. Gross A. Humbert On the contribution of grain boundary sliding type creep to firn densification – an assessment using an optimization approach |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
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 |
T. Schultz R. Müller D. Gross A. Humbert |
author_facet |
T. Schultz R. Müller D. Gross A. Humbert |
author_sort |
T. Schultz |
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 |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-16-143-2022 https://doaj.org/article/0b0592384c3e419aa496d65d5eb7c114 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Antarc* Antarctica Greenland The Cryosphere |
genre_facet |
Antarc* Antarctica Greenland The Cryosphere |
op_source |
The Cryosphere, Vol 16, Pp 143-158 (2022) |
op_relation |
https://tc.copernicus.org/articles/16/143/2022/tc-16-143-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-143-2022 1994-0416 1994-0424 https://doaj.org/article/0b0592384c3e419aa496d65d5eb7c114 |
op_doi |
https://doi.org/10.5194/tc-16-143-2022 |
container_title |
The Cryosphere |
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16 |
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1 |
container_start_page |
143 |
op_container_end_page |
158 |
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1766085719232610304 |