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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fttibhannoverren:oai:oa.tib.eu:123456789/675 2023-05-15T13:24:16+02:00 Antarctic sub-shelf melt rates via PICO Reese, Ronja Albrecht, Torsten Mengel, Matthias Asay-Davis, Xylar Winkelmann, Ricarda 2018 application/pdf https://oa.tib.eu/renate/handle/123456789/675 https://doi.org/10.34657/804 eng eng München : European Geopyhsical Union DOI:https://doi.org/10.5194/tc-12-1969-2018 https://doi.org/10.34657/804 https://oa.tib.eu/renate/handle/123456789/675 CC BY 3.0 Unported https://creativecommons.org/licenses/by/3.0/ frei zugänglich CC-BY The Cryosphere, Volume 12, Issue 6, Page 1969-1985 boundary layer grounding line ice sheet ice shelf ice-ocean interaction iceberg calving oceanic circulation two-dimensional modeling ddc:550 status-type:publishedVersion doc-type:article doc-type:Text 2018 fttibhannoverren https://doi.org/10.34657/804 https://doi.org/10.5194/tc-12-1969-2018 2022-09-19T16:18:15Z 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. Article in Journal/Newspaper Amundsen Sea Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Iceberg* Southern Ocean The Cryosphere Renate - Repositorium für Naturwissenschaften und Technik (TIB Hannover) Amundsen Sea Antarctic Southern Ocean The Antarctic |
institution |
Open Polar |
collection |
Renate - Repositorium für Naturwissenschaften und Technik (TIB Hannover) |
op_collection_id |
fttibhannoverren |
language |
English |
topic |
boundary layer grounding line ice sheet ice shelf ice-ocean interaction iceberg calving oceanic circulation two-dimensional modeling ddc:550 |
spellingShingle |
boundary layer grounding line ice sheet ice shelf ice-ocean interaction iceberg calving oceanic circulation two-dimensional modeling ddc:550 Reese, Ronja Albrecht, Torsten Mengel, Matthias Asay-Davis, Xylar Winkelmann, Ricarda Antarctic sub-shelf melt rates via PICO |
topic_facet |
boundary layer grounding line ice sheet ice shelf ice-ocean interaction iceberg calving oceanic circulation two-dimensional modeling ddc:550 |
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 |
Article in Journal/Newspaper |
author |
Reese, Ronja Albrecht, Torsten Mengel, Matthias Asay-Davis, Xylar Winkelmann, Ricarda |
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 |
publisher |
München : European Geopyhsical Union |
publishDate |
2018 |
url |
https://oa.tib.eu/renate/handle/123456789/675 https://doi.org/10.34657/804 |
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 Iceberg* Southern Ocean The Cryosphere |
genre_facet |
Amundsen Sea Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Iceberg* Southern Ocean The Cryosphere |
op_source |
The Cryosphere, Volume 12, Issue 6, Page 1969-1985 |
op_relation |
DOI:https://doi.org/10.5194/tc-12-1969-2018 https://doi.org/10.34657/804 https://oa.tib.eu/renate/handle/123456789/675 |
op_rights |
CC BY 3.0 Unported https://creativecommons.org/licenses/by/3.0/ frei zugänglich |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.34657/804 https://doi.org/10.5194/tc-12-1969-2018 |
_version_ |
1766378403611541504 |