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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ftdoajarticles:oai:doaj.org/article:e12401ba1c8543d1a20ca2a05d5cd704 2023-05-15T14:00:51+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 2018-01-01T00:00:00Z https://doi.org/10.5194/tc-12-49-2018 https://doaj.org/article/e12401ba1c8543d1a20ca2a05d5cd704 EN eng Copernicus Publications https://www.the-cryosphere.net/12/49/2018/tc-12-49-2018.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-12-49-2018 1994-0416 1994-0424 https://doaj.org/article/e12401ba1c8543d1a20ca2a05d5cd704 The Cryosphere, Vol 12, Pp 49-70 (2018) Environmental sciences GE1-350 Geology QE1-996.5 article 2018 ftdoajarticles https://doi.org/10.5194/tc-12-49-2018 2022-12-31T14:06:17Z 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 Directory of Open Access Journals: DOAJ Articles Antarctic The Antarctic The Cryosphere 12 1 49 70 |
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 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 |
Environmental sciences GE1-350 Geology QE1-996.5 |
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://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 |
https://www.the-cryosphere.net/12/49/2018/tc-12-49-2018.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-12-49-2018 1994-0416 1994-0424 https://doaj.org/article/e12401ba1c8543d1a20ca2a05d5cd704 |
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_ |
1766270186030104576 |