Antarctic sub-shelf melt rates via PICO
Ocean-induced melting below ice shelves is one of the dominant drivers for mass loss from the Antarctic Ice Sheet at present. An appropriate representation of sub-shelf melt rates is therefore essential for model simulations of marine-based ice sheet evolution. Continental-scale ice sheet models oft...
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ftcopernicus:oai:publications.copernicus.org:tc58550 2023-05-15T13:24:13+02:00 Antarctic sub-shelf melt rates via PICO Reese, Ronja Albrecht, Torsten Mengel, Matthias Asay-Davis, Xylar Winkelmann, Ricarda 2019-01-10 application/pdf https://doi.org/10.5194/tc-12-1969-2018 https://tc.copernicus.org/articles/12/1969/2018/ eng eng doi:10.5194/tc-12-1969-2018 https://tc.copernicus.org/articles/12/1969/2018/ eISSN: 1994-0424 Text 2019 ftcopernicus https://doi.org/10.5194/tc-12-1969-2018 2020-07-20T16:23:15Z Ocean-induced melting below ice shelves is one of the dominant drivers for mass loss from the Antarctic Ice Sheet at present. An appropriate representation of sub-shelf melt rates is therefore essential for model simulations of marine-based ice sheet evolution. Continental-scale ice sheet models often rely on simple melt-parameterizations, in particular for long-term simulations, when fully coupled ice–ocean interaction becomes computationally too expensive. Such parameterizations can account for the influence of the local depth of the ice-shelf draft or its slope on melting. However, they do not capture the effect of ocean circulation underneath the ice shelf. Here we present the Potsdam Ice-shelf Cavity mOdel (PICO), which simulates the vertical overturning circulation in ice-shelf cavities and thus enables the computation of sub-shelf melt rates consistent with this circulation. PICO is based on an ocean box model that coarsely resolves ice shelf cavities and uses a boundary layer melt formulation. We implement it as a module of the Parallel Ice Sheet Model (PISM) and evaluate its performance under present-day conditions of the Southern Ocean. We identify a set of parameters that yield two-dimensional melt rate fields that qualitatively reproduce the typical pattern of comparably high melting near the grounding line and lower melting or refreezing towards the calving front. PICO captures the wide range of melt rates observed for Antarctic ice shelves, with an average of about 0.1 m a −1 for cold sub-shelf cavities, for example, underneath Ross or Ronne ice shelves, to 16 m a −1 for warm cavities such as in the Amundsen Sea region. This makes PICO a computationally feasible and more physical alternative to melt parameterizations purely based on ice draft geometry. Text Amundsen Sea Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Southern Ocean Copernicus Publications: E-Journals Amundsen Sea Antarctic Southern Ocean The Antarctic The Cryosphere 12 6 1969 1985 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Ocean-induced melting below ice shelves is one of the dominant drivers for mass loss from the Antarctic Ice Sheet at present. An appropriate representation of sub-shelf melt rates is therefore essential for model simulations of marine-based ice sheet evolution. Continental-scale ice sheet models often rely on simple melt-parameterizations, in particular for long-term simulations, when fully coupled ice–ocean interaction becomes computationally too expensive. Such parameterizations can account for the influence of the local depth of the ice-shelf draft or its slope on melting. However, they do not capture the effect of ocean circulation underneath the ice shelf. Here we present the Potsdam Ice-shelf Cavity mOdel (PICO), which simulates the vertical overturning circulation in ice-shelf cavities and thus enables the computation of sub-shelf melt rates consistent with this circulation. PICO is based on an ocean box model that coarsely resolves ice shelf cavities and uses a boundary layer melt formulation. We implement it as a module of the Parallel Ice Sheet Model (PISM) and evaluate its performance under present-day conditions of the Southern Ocean. We identify a set of parameters that yield two-dimensional melt rate fields that qualitatively reproduce the typical pattern of comparably high melting near the grounding line and lower melting or refreezing towards the calving front. PICO captures the wide range of melt rates observed for Antarctic ice shelves, with an average of about 0.1 m a −1 for cold sub-shelf cavities, for example, underneath Ross or Ronne ice shelves, to 16 m a −1 for warm cavities such as in the Amundsen Sea region. This makes PICO a computationally feasible and more physical alternative to melt parameterizations purely based on ice draft geometry. |
format |
Text |
author |
Reese, Ronja Albrecht, Torsten Mengel, Matthias Asay-Davis, Xylar Winkelmann, Ricarda |
spellingShingle |
Reese, Ronja Albrecht, Torsten Mengel, Matthias Asay-Davis, Xylar Winkelmann, Ricarda Antarctic sub-shelf melt rates via PICO |
author_facet |
Reese, Ronja Albrecht, Torsten Mengel, Matthias Asay-Davis, Xylar Winkelmann, Ricarda |
author_sort |
Reese, Ronja |
title |
Antarctic sub-shelf melt rates via PICO |
title_short |
Antarctic sub-shelf melt rates via PICO |
title_full |
Antarctic sub-shelf melt rates via PICO |
title_fullStr |
Antarctic sub-shelf melt rates via PICO |
title_full_unstemmed |
Antarctic sub-shelf melt rates via PICO |
title_sort |
antarctic sub-shelf melt rates via pico |
publishDate |
2019 |
url |
https://doi.org/10.5194/tc-12-1969-2018 https://tc.copernicus.org/articles/12/1969/2018/ |
geographic |
Amundsen Sea Antarctic Southern Ocean The Antarctic |
geographic_facet |
Amundsen Sea Antarctic Southern Ocean The Antarctic |
genre |
Amundsen Sea Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Southern Ocean |
genre_facet |
Amundsen Sea Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Southern Ocean |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-12-1969-2018 https://tc.copernicus.org/articles/12/1969/2018/ |
op_doi |
https://doi.org/10.5194/tc-12-1969-2018 |
container_title |
The Cryosphere |
container_volume |
12 |
container_issue |
6 |
container_start_page |
1969 |
op_container_end_page |
1985 |
_version_ |
1766378142164844544 |