Greenland's firn responds more to warming than to cooling
The porous layer of snow and firn on the Greenland Ice Sheet stores meltwater and limits the rate at which the ice sheet contributes to sea level rise. This buffer is threatened in a warming climate. To better understand the nature and timescales of firn's response to air temperature change on...
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Online Access: | https://doi.org/10.5194/tc-18-3333-2024 https://tc.copernicus.org/articles/18/3333/2024/ |
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ftcopernicus:oai:publications.copernicus.org:tc115863 2024-09-15T18:08:57+00:00 Greenland's firn responds more to warming than to cooling Thompson-Munson, Megan Kay, Jennifer E. Markle, Bradley R. 2024-07-24 application/pdf https://doi.org/10.5194/tc-18-3333-2024 https://tc.copernicus.org/articles/18/3333/2024/ eng eng doi:10.5194/tc-18-3333-2024 https://tc.copernicus.org/articles/18/3333/2024/ eISSN: 1994-0424 Text 2024 ftcopernicus https://doi.org/10.5194/tc-18-3333-2024 2024-07-26T00:08:26Z The porous layer of snow and firn on the Greenland Ice Sheet stores meltwater and limits the rate at which the ice sheet contributes to sea level rise. This buffer is threatened in a warming climate. To better understand the nature and timescales of firn's response to air temperature change on the Greenland Ice Sheet, we use a physics-based model to assess the effects of atmospheric warming and cooling on Greenland's firn air content in idealized climate experiments. We identify an asymmetric response of Greenland's firn to air temperature: firn loses more air content due to warming compared to the amount gained from commensurate cooling. 100 years after a 1 °C temperature perturbation, warming decreases the spatially integrated air content by 9.7 %, and cooling increases it by 8.3 %. In dry firn, this asymmetry is driven by the highly nonlinear relationship between temperature and firn compaction, as well as the dependence of thermal conductivity on the composition of the firn. The influence of liquid water accentuates this asymmetry. In wet firn areas, melt increases nonlinearly with atmospheric warming, thus enhancing firn refreezing and further warming the snowpack through increased latent heat release. Our results highlight the vulnerability of Greenland firn to temperature change and demonstrate that firn air content is more efficiently depleted than generated. This asymmetry in the temperature–firn relationship may contribute to the overall temporally asymmetric mass change of the Greenland Ice Sheet in a changing climate across many timescales. Text Greenland Ice Sheet Copernicus Publications: E-Journals The Cryosphere 18 7 3333 3350 |
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Copernicus Publications: E-Journals |
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English |
description |
The porous layer of snow and firn on the Greenland Ice Sheet stores meltwater and limits the rate at which the ice sheet contributes to sea level rise. This buffer is threatened in a warming climate. To better understand the nature and timescales of firn's response to air temperature change on the Greenland Ice Sheet, we use a physics-based model to assess the effects of atmospheric warming and cooling on Greenland's firn air content in idealized climate experiments. We identify an asymmetric response of Greenland's firn to air temperature: firn loses more air content due to warming compared to the amount gained from commensurate cooling. 100 years after a 1 °C temperature perturbation, warming decreases the spatially integrated air content by 9.7 %, and cooling increases it by 8.3 %. In dry firn, this asymmetry is driven by the highly nonlinear relationship between temperature and firn compaction, as well as the dependence of thermal conductivity on the composition of the firn. The influence of liquid water accentuates this asymmetry. In wet firn areas, melt increases nonlinearly with atmospheric warming, thus enhancing firn refreezing and further warming the snowpack through increased latent heat release. Our results highlight the vulnerability of Greenland firn to temperature change and demonstrate that firn air content is more efficiently depleted than generated. This asymmetry in the temperature–firn relationship may contribute to the overall temporally asymmetric mass change of the Greenland Ice Sheet in a changing climate across many timescales. |
format |
Text |
author |
Thompson-Munson, Megan Kay, Jennifer E. Markle, Bradley R. |
spellingShingle |
Thompson-Munson, Megan Kay, Jennifer E. Markle, Bradley R. Greenland's firn responds more to warming than to cooling |
author_facet |
Thompson-Munson, Megan Kay, Jennifer E. Markle, Bradley R. |
author_sort |
Thompson-Munson, Megan |
title |
Greenland's firn responds more to warming than to cooling |
title_short |
Greenland's firn responds more to warming than to cooling |
title_full |
Greenland's firn responds more to warming than to cooling |
title_fullStr |
Greenland's firn responds more to warming than to cooling |
title_full_unstemmed |
Greenland's firn responds more to warming than to cooling |
title_sort |
greenland's firn responds more to warming than to cooling |
publishDate |
2024 |
url |
https://doi.org/10.5194/tc-18-3333-2024 https://tc.copernicus.org/articles/18/3333/2024/ |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-18-3333-2024 https://tc.copernicus.org/articles/18/3333/2024/ |
op_doi |
https://doi.org/10.5194/tc-18-3333-2024 |
container_title |
The Cryosphere |
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18 |
container_issue |
7 |
container_start_page |
3333 |
op_container_end_page |
3350 |
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1810446325295087616 |