Modelling present-day basal melt rates for Antarctic ice shelves using a parametrization of buoyant meltwater plumes
Basal melting below ice shelves is a major factor in mass loss from the Antarctic Ice Sheet, which can contribute significantly to possible future sea-level rise. Therefore, it is important to have an adequate description of the basal melt rates for use in ice-dynamical models. Most current ice mode...
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fttriple:oai:gotriple.eu:oai:doaj.org/article:e12401ba1c8543d1a20ca2a05d5cd704 2023-05-15T14:03:52+02:00 Modelling present-day basal melt rates for Antarctic ice shelves using a parametrization of buoyant meltwater plumes W. M. J. Lazeroms A. Jenkins G. H. Gudmundsson R. S. W. van de Wal 2018-01-01 https://doi.org/10.5194/tc-12-49-2018 https://www.the-cryosphere.net/12/49/2018/tc-12-49-2018.pdf https://doaj.org/article/e12401ba1c8543d1a20ca2a05d5cd704 en eng Copernicus Publications doi:10.5194/tc-12-49-2018 1994-0416 1994-0424 https://www.the-cryosphere.net/12/49/2018/tc-12-49-2018.pdf https://doaj.org/article/e12401ba1c8543d1a20ca2a05d5cd704 undefined The Cryosphere, Vol 12, Pp 49-70 (2018) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2018 fttriple https://doi.org/10.5194/tc-12-49-2018 2023-01-22T17:53:05Z Basal melting below ice shelves is a major factor in mass loss from the Antarctic Ice Sheet, which can contribute significantly to possible future sea-level rise. Therefore, it is important to have an adequate description of the basal melt rates for use in ice-dynamical models. Most current ice models use rather simple parametrizations based on the local balance of heat between ice and ocean. In this work, however, we use a recently derived parametrization of the melt rates based on a buoyant meltwater plume travelling upward beneath an ice shelf. This plume parametrization combines a non-linear ocean temperature sensitivity with an inherent geometry dependence, which is mainly described by the grounding-line depth and the local slope of the ice-shelf base. For the first time, this type of parametrization is evaluated on a two-dimensional grid covering the entire Antarctic continent. In order to apply the essentially one-dimensional parametrization to realistic ice-shelf geometries, we present an algorithm that determines effective values for the grounding-line depth and basal slope in any point beneath an ice shelf. Furthermore, since detailed knowledge of temperatures and circulation patterns in the ice-shelf cavities is sparse or absent, we construct an effective ocean temperature field from observational data with the purpose of matching (area-averaged) melt rates from the model with observed present-day melt rates. Our results qualitatively replicate large-scale observed features in basal melt rates around Antarctica, not only in terms of average values, but also in terms of the spatial pattern, with high melt rates typically occurring near the grounding line. The plume parametrization and the effective temperature field presented here are therefore promising tools for future simulations of the Antarctic Ice Sheet requiring a more realistic oceanic forcing. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Ice Shelves The Cryosphere Unknown Antarctic The Antarctic The Cryosphere 12 1 49 70 |
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language |
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geo envir W. M. J. Lazeroms A. Jenkins G. H. Gudmundsson R. S. W. van de Wal Modelling present-day basal melt rates for Antarctic ice shelves using a parametrization of buoyant meltwater plumes |
topic_facet |
geo envir |
description |
Basal melting below ice shelves is a major factor in mass loss from the Antarctic Ice Sheet, which can contribute significantly to possible future sea-level rise. Therefore, it is important to have an adequate description of the basal melt rates for use in ice-dynamical models. Most current ice models use rather simple parametrizations based on the local balance of heat between ice and ocean. In this work, however, we use a recently derived parametrization of the melt rates based on a buoyant meltwater plume travelling upward beneath an ice shelf. This plume parametrization combines a non-linear ocean temperature sensitivity with an inherent geometry dependence, which is mainly described by the grounding-line depth and the local slope of the ice-shelf base. For the first time, this type of parametrization is evaluated on a two-dimensional grid covering the entire Antarctic continent. In order to apply the essentially one-dimensional parametrization to realistic ice-shelf geometries, we present an algorithm that determines effective values for the grounding-line depth and basal slope in any point beneath an ice shelf. Furthermore, since detailed knowledge of temperatures and circulation patterns in the ice-shelf cavities is sparse or absent, we construct an effective ocean temperature field from observational data with the purpose of matching (area-averaged) melt rates from the model with observed present-day melt rates. Our results qualitatively replicate large-scale observed features in basal melt rates around Antarctica, not only in terms of average values, but also in terms of the spatial pattern, with high melt rates typically occurring near the grounding line. The plume parametrization and the effective temperature field presented here are therefore promising tools for future simulations of the Antarctic Ice Sheet requiring a more realistic oceanic forcing. |
format |
Article in Journal/Newspaper |
author |
W. M. J. Lazeroms A. Jenkins G. H. Gudmundsson R. S. W. van de Wal |
author_facet |
W. M. J. Lazeroms A. Jenkins G. H. Gudmundsson R. S. W. van de Wal |
author_sort |
W. M. J. Lazeroms |
title |
Modelling present-day basal melt rates for Antarctic ice shelves using a parametrization of buoyant meltwater plumes |
title_short |
Modelling present-day basal melt rates for Antarctic ice shelves using a parametrization of buoyant meltwater plumes |
title_full |
Modelling present-day basal melt rates for Antarctic ice shelves using a parametrization of buoyant meltwater plumes |
title_fullStr |
Modelling present-day basal melt rates for Antarctic ice shelves using a parametrization of buoyant meltwater plumes |
title_full_unstemmed |
Modelling present-day basal melt rates for Antarctic ice shelves using a parametrization of buoyant meltwater plumes |
title_sort |
modelling present-day basal melt rates for antarctic ice shelves using a parametrization of buoyant meltwater plumes |
publisher |
Copernicus Publications |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-12-49-2018 https://www.the-cryosphere.net/12/49/2018/tc-12-49-2018.pdf https://doaj.org/article/e12401ba1c8543d1a20ca2a05d5cd704 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Ice Shelves The Cryosphere |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Ice Shelves The Cryosphere |
op_source |
The Cryosphere, Vol 12, Pp 49-70 (2018) |
op_relation |
doi:10.5194/tc-12-49-2018 1994-0416 1994-0424 https://www.the-cryosphere.net/12/49/2018/tc-12-49-2018.pdf https://doaj.org/article/e12401ba1c8543d1a20ca2a05d5cd704 |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-12-49-2018 |
container_title |
The Cryosphere |
container_volume |
12 |
container_issue |
1 |
container_start_page |
49 |
op_container_end_page |
70 |
_version_ |
1766274735803465728 |