A new model of dry firn-densification constrained by continuous strain measurements near South Pole
Converting measurements of ice-sheet surface elevation change to mass change requires measurements of accumulation and knowledge of the evolution of the density profile in the firn. Most firn-densification models are tuned using measured depth–density profiles, a method which is based on an assumpti...
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2023-12-01
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| Series: | Journal of Glaciology |
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| Online Access: | https://www.cambridge.org/core/product/identifier/S0022143023000874/type/journal_article |
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| author | C. Max Stevens David A. Lilien Howard Conway T. J. Fudge Michelle R. Koutnik Edwin D. Waddington |
| author_facet | C. Max Stevens David A. Lilien Howard Conway T. J. Fudge Michelle R. Koutnik Edwin D. Waddington |
| author_sort | C. Max Stevens |
| collection | DOAJ |
| description | Converting measurements of ice-sheet surface elevation change to mass change requires measurements of accumulation and knowledge of the evolution of the density profile in the firn. Most firn-densification models are tuned using measured depth–density profiles, a method which is based on an assumption that the density profile in the firn is invariant through time. Here we present continuous measurements of firn-compaction rates in 12 boreholes near the South Pole over a 2 year period. To our knowledge, these are the first continuous measurements of firn compaction on the Antarctic plateau. We use the data to derive a new firn-densification algorithm framed as a constitutive relationship. We also compare our measurements to compaction rates predicted by several existing firn-densification models. Results indicate that an activation energy of 60 kJ mol−1, a value within the range used by current models, best predicts the seasonal cycle in compaction rates on the Antarctic plateau. Our results suggest models can predict firn-compaction rates with at best 7% uncertainty and cumulative firn compaction on a 2 year timescale with at best 8% uncertainty. |
| format | Article |
| id | doaj-art-d725d94676d44dd99dde3e01e5f8dbf4 |
| institution | OA Journals |
| issn | 0022-1430 1727-5652 |
| language | English |
| publishDate | 2023-12-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Journal of Glaciology |
| spelling | doaj-art-d725d94676d44dd99dde3e01e5f8dbf42025-08-20T01:59:01ZengCambridge University PressJournal of Glaciology0022-14301727-56522023-12-01692099211310.1017/jog.2023.87A new model of dry firn-densification constrained by continuous strain measurements near South PoleC. Max Stevens0https://orcid.org/0000-0003-2005-0876David A. Lilien1https://orcid.org/0000-0001-8667-8020Howard Conway2T. J. Fudge3https://orcid.org/0000-0002-6818-7479Michelle R. Koutnik4Edwin D. Waddington5https://orcid.org/0000-0003-4947-3223Department of Earth and Space Sciences, University of Washington, Seattle, WA, USA Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USADepartment of Earth and Space Sciences, University of Washington, Seattle, WA, USA Centre for Earth Observation Science, University of Manitoba, Winnipeg, MB, CanadaDepartment of Earth and Space Sciences, University of Washington, Seattle, WA, USADepartment of Earth and Space Sciences, University of Washington, Seattle, WA, USADepartment of Earth and Space Sciences, University of Washington, Seattle, WA, USADepartment of Earth and Space Sciences, University of Washington, Seattle, WA, USAConverting measurements of ice-sheet surface elevation change to mass change requires measurements of accumulation and knowledge of the evolution of the density profile in the firn. Most firn-densification models are tuned using measured depth–density profiles, a method which is based on an assumption that the density profile in the firn is invariant through time. Here we present continuous measurements of firn-compaction rates in 12 boreholes near the South Pole over a 2 year period. To our knowledge, these are the first continuous measurements of firn compaction on the Antarctic plateau. We use the data to derive a new firn-densification algorithm framed as a constitutive relationship. We also compare our measurements to compaction rates predicted by several existing firn-densification models. Results indicate that an activation energy of 60 kJ mol−1, a value within the range used by current models, best predicts the seasonal cycle in compaction rates on the Antarctic plateau. Our results suggest models can predict firn-compaction rates with at best 7% uncertainty and cumulative firn compaction on a 2 year timescale with at best 8% uncertainty.https://www.cambridge.org/core/product/identifier/S0022143023000874/type/journal_articleAntarctic glaciologyglaciological instruments and methodspolar firnsnow/ice surface processessnow rheology |
| spellingShingle | C. Max Stevens David A. Lilien Howard Conway T. J. Fudge Michelle R. Koutnik Edwin D. Waddington A new model of dry firn-densification constrained by continuous strain measurements near South Pole Journal of Glaciology Antarctic glaciology glaciological instruments and methods polar firn snow/ice surface processes snow rheology |
| title | A new model of dry firn-densification constrained by continuous strain measurements near South Pole |
| title_full | A new model of dry firn-densification constrained by continuous strain measurements near South Pole |
| title_fullStr | A new model of dry firn-densification constrained by continuous strain measurements near South Pole |
| title_full_unstemmed | A new model of dry firn-densification constrained by continuous strain measurements near South Pole |
| title_short | A new model of dry firn-densification constrained by continuous strain measurements near South Pole |
| title_sort | new model of dry firn densification constrained by continuous strain measurements near south pole |
| topic | Antarctic glaciology glaciological instruments and methods polar firn snow/ice surface processes snow rheology |
| url | https://www.cambridge.org/core/product/identifier/S0022143023000874/type/journal_article |
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