Adjoint sensitivities of sub-ice shelf melt rates to ocean circulation under Pine Island Ice Shelf, West Antarctica
We investigate the sensitivity of sub-ice-shelf melt rates under Pine Island Ice Shelf, West Antarctica, to changes in the oceanic state using an adjoint ocean model that is capable of representing the flow in sub-ice-shelf cavities. The adjoint code is based on algorithmic differentiation (AD) of t...
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ftawi:oai:epic.awi.de:24588 2024-09-15T17:39:59+00:00 Adjoint sensitivities of sub-ice shelf melt rates to ocean circulation under Pine Island Ice Shelf, West Antarctica Heimbach, Patrick Losch, Martin 2012 application/pdf https://epic.awi.de/id/eprint/24588/ https://epic.awi.de/id/eprint/24588/1/Hei2011b.pdf https://hdl.handle.net/10013/epic.38891 https://hdl.handle.net/10013/epic.38891.d001 unknown https://epic.awi.de/id/eprint/24588/1/Hei2011b.pdf https://hdl.handle.net/10013/epic.38891.d001 Heimbach, P. and Losch, M. orcid:0000-0002-3824-5244 (2012) Adjoint sensitivities of sub-ice shelf melt rates to ocean circulation under Pine Island Ice Shelf, West Antarctica , Annals of Glaciology, 53 (60), pp. 59-69 . doi:10.3189/2012/AoG60A025 <https://doi.org/10.3189/2012%2FAoG60A025> , hdl:10013/epic.38891 EPIC3Annals of Glaciology, 53(60), pp. 59-69, ISSN: 0260-3055 Article isiRev 2012 ftawi https://doi.org/10.3189/2012/AoG60A025 2024-06-24T04:02:42Z We investigate the sensitivity of sub-ice-shelf melt rates under Pine Island Ice Shelf, West Antarctica, to changes in the oceanic state using an adjoint ocean model that is capable of representing the flow in sub-ice-shelf cavities. The adjoint code is based on algorithmic differentiation (AD) of the Massachusetts Institute of Technology’s ocean general circulation model (MITgcm). The adjoint model was extended by adding into the AD process the corresponding sub-ice-shelf cavity code, which implements a three-equation thermodynamic melt-rate parameterization to infer heat and freshwater fluxes at the ice-shelf/ocean boundary. The inferred sensitivities reveal dominant timescales of 30–60 days over which the shelf exit is connected to the deep interior via advective processes. They exhibit rich three-dimensional time-evolving patterns that can be understood in terms of a combination of the buoyancy forcing by inflowing water masses, the cavity geometry and the effect of rotation and topography in steering the flow in the presence of prominent features in the bedrock bathymetry. Dominant sensitivity pathways are found over a sill, as well as ‘shadow regions’ of very low sensitivities. To the extent that these transient patterns are robust they carry important information for decision- making in observation deployment and monitoring. Article in Journal/Newspaper Annals of Glaciology Antarc* Antarctica Ice Shelf Pine Island West Antarctica Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Annals of Glaciology 53 60 59 69 |
institution |
Open Polar |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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ftawi |
language |
unknown |
description |
We investigate the sensitivity of sub-ice-shelf melt rates under Pine Island Ice Shelf, West Antarctica, to changes in the oceanic state using an adjoint ocean model that is capable of representing the flow in sub-ice-shelf cavities. The adjoint code is based on algorithmic differentiation (AD) of the Massachusetts Institute of Technology’s ocean general circulation model (MITgcm). The adjoint model was extended by adding into the AD process the corresponding sub-ice-shelf cavity code, which implements a three-equation thermodynamic melt-rate parameterization to infer heat and freshwater fluxes at the ice-shelf/ocean boundary. The inferred sensitivities reveal dominant timescales of 30–60 days over which the shelf exit is connected to the deep interior via advective processes. They exhibit rich three-dimensional time-evolving patterns that can be understood in terms of a combination of the buoyancy forcing by inflowing water masses, the cavity geometry and the effect of rotation and topography in steering the flow in the presence of prominent features in the bedrock bathymetry. Dominant sensitivity pathways are found over a sill, as well as ‘shadow regions’ of very low sensitivities. To the extent that these transient patterns are robust they carry important information for decision- making in observation deployment and monitoring. |
format |
Article in Journal/Newspaper |
author |
Heimbach, Patrick Losch, Martin |
spellingShingle |
Heimbach, Patrick Losch, Martin Adjoint sensitivities of sub-ice shelf melt rates to ocean circulation under Pine Island Ice Shelf, West Antarctica |
author_facet |
Heimbach, Patrick Losch, Martin |
author_sort |
Heimbach, Patrick |
title |
Adjoint sensitivities of sub-ice shelf melt rates to ocean circulation under Pine Island Ice Shelf, West Antarctica |
title_short |
Adjoint sensitivities of sub-ice shelf melt rates to ocean circulation under Pine Island Ice Shelf, West Antarctica |
title_full |
Adjoint sensitivities of sub-ice shelf melt rates to ocean circulation under Pine Island Ice Shelf, West Antarctica |
title_fullStr |
Adjoint sensitivities of sub-ice shelf melt rates to ocean circulation under Pine Island Ice Shelf, West Antarctica |
title_full_unstemmed |
Adjoint sensitivities of sub-ice shelf melt rates to ocean circulation under Pine Island Ice Shelf, West Antarctica |
title_sort |
adjoint sensitivities of sub-ice shelf melt rates to ocean circulation under pine island ice shelf, west antarctica |
publishDate |
2012 |
url |
https://epic.awi.de/id/eprint/24588/ https://epic.awi.de/id/eprint/24588/1/Hei2011b.pdf https://hdl.handle.net/10013/epic.38891 https://hdl.handle.net/10013/epic.38891.d001 |
genre |
Annals of Glaciology Antarc* Antarctica Ice Shelf Pine Island West Antarctica |
genre_facet |
Annals of Glaciology Antarc* Antarctica Ice Shelf Pine Island West Antarctica |
op_source |
EPIC3Annals of Glaciology, 53(60), pp. 59-69, ISSN: 0260-3055 |
op_relation |
https://epic.awi.de/id/eprint/24588/1/Hei2011b.pdf https://hdl.handle.net/10013/epic.38891.d001 Heimbach, P. and Losch, M. orcid:0000-0002-3824-5244 (2012) Adjoint sensitivities of sub-ice shelf melt rates to ocean circulation under Pine Island Ice Shelf, West Antarctica , Annals of Glaciology, 53 (60), pp. 59-69 . doi:10.3189/2012/AoG60A025 <https://doi.org/10.3189/2012%2FAoG60A025> , hdl:10013/epic.38891 |
op_doi |
https://doi.org/10.3189/2012/AoG60A025 |
container_title |
Annals of Glaciology |
container_volume |
53 |
container_issue |
60 |
container_start_page |
59 |
op_container_end_page |
69 |
_version_ |
1810483928366055424 |