Sensitivity of the Lambert-Amery glacial system to geothermal heat flux
Geothermal heat flux (GHF) is one of the key thermal boundary conditions for ice-sheet models. We assess the sensitivity of the Lambert-Amery glacial system in East Antarctica to four different GHF datasets using a regional ice-sheet model. A control solution of the regional model is initialised by...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2016-09-01
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| Series: | Annals of Glaciology |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S0260305516000264/type/journal_article |
| _version_ | 1811157269558067200 |
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| author | M. L. Pittard J. L. Roberts B. K. Galton-Fenzi C. S. Watson |
| author_facet | M. L. Pittard J. L. Roberts B. K. Galton-Fenzi C. S. Watson |
| author_sort | M. L. Pittard |
| collection | DOAJ |
| description | Geothermal heat flux (GHF) is one of the key thermal boundary conditions for ice-sheet models. We assess the sensitivity of the Lambert-Amery glacial system in East Antarctica to four different GHF datasets using a regional ice-sheet model. A control solution of the regional model is initialised by minimising the misfit to observations through an optimisation process. The Lambert-Amery glacial system simulation contains temperate ice up to 150 m thick and has an average basal melt of 1.3 mm a−1, with maximum basal melting of 504 mm a−1. The simulations which use a relatively high GHF compared to the control solution increase the volume and area of temperate ice, which causes higher surface velocities at higher elevations, which leads to the advance of the grounding line. The grounding line advance leads to changes in the local flow configuration, which dominates the changes within the glacial system. To investigate the difference in spatial patterns within the geothermal datasets, they were scaled to have the same median value. These scaled GHF simulations showed that the ice flow was most sensitive to the spatial variation in the underlying GHF near the ice divides and on the edges of the ice streams. |
| first_indexed | 2024-04-10T05:04:26Z |
| format | Article |
| id | doaj.art-1b911418434c4c2cad0fe05691025a42 |
| institution | Directory Open Access Journal |
| issn | 0260-3055 1727-5644 |
| language | English |
| last_indexed | 2024-04-10T05:04:26Z |
| publishDate | 2016-09-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Annals of Glaciology |
| spelling | doaj.art-1b911418434c4c2cad0fe05691025a422023-03-09T12:27:29ZengCambridge University PressAnnals of Glaciology0260-30551727-56442016-09-0157566810.1017/aog.2016.26Sensitivity of the Lambert-Amery glacial system to geothermal heat fluxM. L. Pittard0J. L. Roberts1B. K. Galton-Fenzi2C. S. Watson3Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia E-mail: Antarctic Climate & Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, Tasmania, AustraliaAntarctic Climate & Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, Tasmania, Australia Australian Antarctic Division, Kingston, Tasmania, AustraliaAntarctic Climate & Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, Tasmania, Australia Australian Antarctic Division, Kingston, Tasmania, AustraliaSchool of Land and Food, University of Tasmania, Hobart, Tasmania, AustraliaGeothermal heat flux (GHF) is one of the key thermal boundary conditions for ice-sheet models. We assess the sensitivity of the Lambert-Amery glacial system in East Antarctica to four different GHF datasets using a regional ice-sheet model. A control solution of the regional model is initialised by minimising the misfit to observations through an optimisation process. The Lambert-Amery glacial system simulation contains temperate ice up to 150 m thick and has an average basal melt of 1.3 mm a−1, with maximum basal melting of 504 mm a−1. The simulations which use a relatively high GHF compared to the control solution increase the volume and area of temperate ice, which causes higher surface velocities at higher elevations, which leads to the advance of the grounding line. The grounding line advance leads to changes in the local flow configuration, which dominates the changes within the glacial system. To investigate the difference in spatial patterns within the geothermal datasets, they were scaled to have the same median value. These scaled GHF simulations showed that the ice flow was most sensitive to the spatial variation in the underlying GHF near the ice divides and on the edges of the ice streams.https://www.cambridge.org/core/product/identifier/S0260305516000264/type/journal_articlegeothermal heat fluxice-sheet modelsubglacial hydrology |
| spellingShingle | M. L. Pittard J. L. Roberts B. K. Galton-Fenzi C. S. Watson Sensitivity of the Lambert-Amery glacial system to geothermal heat flux Annals of Glaciology geothermal heat flux ice-sheet model subglacial hydrology |
| title | Sensitivity of the Lambert-Amery glacial system to geothermal heat flux |
| title_full | Sensitivity of the Lambert-Amery glacial system to geothermal heat flux |
| title_fullStr | Sensitivity of the Lambert-Amery glacial system to geothermal heat flux |
| title_full_unstemmed | Sensitivity of the Lambert-Amery glacial system to geothermal heat flux |
| title_short | Sensitivity of the Lambert-Amery glacial system to geothermal heat flux |
| title_sort | sensitivity of the lambert amery glacial system to geothermal heat flux |
| topic | geothermal heat flux ice-sheet model subglacial hydrology |
| url | https://www.cambridge.org/core/product/identifier/S0260305516000264/type/journal_article |
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