Subglacial hydrology modulates basal sliding response of the Antarctic ice sheet to climate forcing
<p>Major uncertainties in the response of ice sheets to environmental forcing are due to subglacial processes. These processes pertain to the type of sliding or friction law as well as the spatial and temporal evolution of the effective pressure at the base of ice sheets. We evaluate the class...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-10-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/16/4537/2022/tc-16-4537-2022.pdf |
| _version_ | 1811198309884231680 |
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| author | E. Kazmierczak S. Sun S. Sun V. Coulon F. Pattyn |
| author_facet | E. Kazmierczak S. Sun S. Sun V. Coulon F. Pattyn |
| author_sort | E. Kazmierczak |
| collection | DOAJ |
| description | <p>Major uncertainties in the response of ice sheets to environmental forcing are due to subglacial processes. These processes pertain to the type of sliding or friction law as well as the spatial and temporal evolution of the effective pressure at the base of ice sheets. We evaluate the classic Weertman–Budd sliding law for different power exponents (viscous to near plastic) and for different representations of effective pressure at the base of the ice sheet, commonly used for hard and soft beds. The sensitivity of the above slip laws is evaluated for the Antarctic ice sheet in two types of experiments: (i) the ABUMIP experiments in which ice shelves are instantaneously removed, leading to rapid grounding-line retreat and ice sheet collapse, and (ii) the ISMIP6 experiments with realistic ocean and atmosphere forcings for different Representative Concentration Pathway (RCP) scenarios. Results confirm earlier work that the power in the sliding law is the most determining factor in the sensitivity of the ice sheet to climatic forcing, where a higher power in the sliding law leads to increased mass loss for a given forcing. Here we show that spatial and temporal changes in water pressure or water flux at the base modulate basal sliding for a given power, especially for high-end scenarios, such as ABUMIP. In particular, subglacial models depending on subglacial water pressure decrease effective pressure significantly near the grounding line, leading to an increased sensitivity to climatic forcing for a given power in the sliding law. This dependency is, however, less clear under realistic forcing scenarios (ISMIP6).</p> |
| first_indexed | 2024-04-12T01:28:11Z |
| format | Article |
| id | doaj.art-1bb185d3c88a4591bac04951ce34564c |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-04-12T01:28:11Z |
| publishDate | 2022-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-1bb185d3c88a4591bac04951ce34564c2022-12-22T03:53:33ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242022-10-01164537455210.5194/tc-16-4537-2022Subglacial hydrology modulates basal sliding response of the Antarctic ice sheet to climate forcingE. Kazmierczak0S. Sun1S. Sun2V. Coulon3F. Pattyn4Laboratoire de Glaciologie, Université libre de Bruxelles (ULB), Brussels, BelgiumLaboratoire de Glaciologie, Université libre de Bruxelles (ULB), Brussels, BelgiumDepartment of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, UKLaboratoire de Glaciologie, Université libre de Bruxelles (ULB), Brussels, BelgiumLaboratoire de Glaciologie, Université libre de Bruxelles (ULB), Brussels, Belgium<p>Major uncertainties in the response of ice sheets to environmental forcing are due to subglacial processes. These processes pertain to the type of sliding or friction law as well as the spatial and temporal evolution of the effective pressure at the base of ice sheets. We evaluate the classic Weertman–Budd sliding law for different power exponents (viscous to near plastic) and for different representations of effective pressure at the base of the ice sheet, commonly used for hard and soft beds. The sensitivity of the above slip laws is evaluated for the Antarctic ice sheet in two types of experiments: (i) the ABUMIP experiments in which ice shelves are instantaneously removed, leading to rapid grounding-line retreat and ice sheet collapse, and (ii) the ISMIP6 experiments with realistic ocean and atmosphere forcings for different Representative Concentration Pathway (RCP) scenarios. Results confirm earlier work that the power in the sliding law is the most determining factor in the sensitivity of the ice sheet to climatic forcing, where a higher power in the sliding law leads to increased mass loss for a given forcing. Here we show that spatial and temporal changes in water pressure or water flux at the base modulate basal sliding for a given power, especially for high-end scenarios, such as ABUMIP. In particular, subglacial models depending on subglacial water pressure decrease effective pressure significantly near the grounding line, leading to an increased sensitivity to climatic forcing for a given power in the sliding law. This dependency is, however, less clear under realistic forcing scenarios (ISMIP6).</p>https://tc.copernicus.org/articles/16/4537/2022/tc-16-4537-2022.pdf |
| spellingShingle | E. Kazmierczak S. Sun S. Sun V. Coulon F. Pattyn Subglacial hydrology modulates basal sliding response of the Antarctic ice sheet to climate forcing The Cryosphere |
| title | Subglacial hydrology modulates basal sliding response of the Antarctic ice sheet to climate forcing |
| title_full | Subglacial hydrology modulates basal sliding response of the Antarctic ice sheet to climate forcing |
| title_fullStr | Subglacial hydrology modulates basal sliding response of the Antarctic ice sheet to climate forcing |
| title_full_unstemmed | Subglacial hydrology modulates basal sliding response of the Antarctic ice sheet to climate forcing |
| title_short | Subglacial hydrology modulates basal sliding response of the Antarctic ice sheet to climate forcing |
| title_sort | subglacial hydrology modulates basal sliding response of the antarctic ice sheet to climate forcing |
| url | https://tc.copernicus.org/articles/16/4537/2022/tc-16-4537-2022.pdf |
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