Topographic shelf waves control seasonal melting near Antarctic Ice Shelf grounding lines
The buttressing potential of ice shelves is modulated by changes in subshelf melting, in response to changing ocean conditions. We analyze the temporal variability in subshelf melting using an autonomous phase-sensitive radio-echo sounder near the grounding line of the Roi Baudouin Ice Shelf in East...
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American Geophysical Union
2019
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Online Access: | http://nora.nerc.ac.uk/id/eprint/525689/ https://nora.nerc.ac.uk/id/eprint/525689/1/2019GL083881.pdf https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083881 |
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ftnerc:oai:nora.nerc.ac.uk:525689 2023-05-15T13:41:44+02:00 Topographic shelf waves control seasonal melting near Antarctic Ice Shelf grounding lines Sun, Sainan Hattermann, Tore Pattyn, Frank Nicholls, Keith W. Drews, Reinhard Berger, Sophie 2019-10-02 text http://nora.nerc.ac.uk/id/eprint/525689/ https://nora.nerc.ac.uk/id/eprint/525689/1/2019GL083881.pdf https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083881 en eng American Geophysical Union https://nora.nerc.ac.uk/id/eprint/525689/1/2019GL083881.pdf Sun, Sainan; Hattermann, Tore; Pattyn, Frank; Nicholls, Keith W. orcid:0000-0002-2188-4509 Drews, Reinhard; Berger, Sophie. 2019 Topographic shelf waves control seasonal melting near Antarctic Ice Shelf grounding lines. Geophysical Research Letters, 46 (16). 9824-9832. https://doi.org/10.1029/2019GL083881 <https://doi.org/10.1029/2019GL083881> Publication - Article PeerReviewed 2019 ftnerc https://doi.org/10.1029/2019GL083881 2023-02-04T19:49:32Z The buttressing potential of ice shelves is modulated by changes in subshelf melting, in response to changing ocean conditions. We analyze the temporal variability in subshelf melting using an autonomous phase-sensitive radio-echo sounder near the grounding line of the Roi Baudouin Ice Shelf in East Antarctica. When combined with additional oceanographic evidence of seasonal variations in the stratification and the amplification of diurnal tides around the shelf break topography (Gunnerus Bank), the results suggest an intricate mechanism in which topographic waves control the seasonal melt rate variability near the grounding line. This mechanism has not been considered before and has the potential to enhance local melt rates without advecting different water masses. As topographic waves seem to strengthen in a stratified ocean, the freshening of Antarctic surface water, predicted by observations and models, is likely to increase future basal melting in this area. Plain Language Summary Ice shelves (or the floating parts of the Antarctic ice sheet) lose primarily mass through melting at their bottom in contact with the ocean. This thins them and makes them more vulnerable to potential collapse. To understand the processes governing such thinning, direct and long-time measurements are essential. Here we report on the first high-resolution time series of direct melt measurements on the Roi Baudouin Ice Shelf in Dronning Maud Land during 2016. We find that subshelf melt varies on both seasonal and daily time scales. Temporal variations stem from topographical ocean waves that originate on the continental shelf and transfer ocean properties without time delay within the ice shelf cavity. Therefore, seasonal variations highly depend on the presence/absence of sea ice in front of the ice shelf, which impact the strength of topographical waves. This mechanism is highly efficient at increasing the ice-ocean exchanges and may explain regional differences in ice shelf melt. Article in Journal/Newspaper Antarc* Antarctic Antarctica Dronning Maud Land East Antarctica Ice Sheet Ice Shelf Ice Shelves Sea ice Natural Environment Research Council: NERC Open Research Archive Antarctic The Antarctic East Antarctica Dronning Maud Land Roi Baudouin ENVELOPE(24.461,24.461,-70.438,-70.438) Gunnerus Bank ENVELOPE(33.000,33.000,-68.000,-68.000) Geophysical Research Letters 46 16 9824 9832 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
The buttressing potential of ice shelves is modulated by changes in subshelf melting, in response to changing ocean conditions. We analyze the temporal variability in subshelf melting using an autonomous phase-sensitive radio-echo sounder near the grounding line of the Roi Baudouin Ice Shelf in East Antarctica. When combined with additional oceanographic evidence of seasonal variations in the stratification and the amplification of diurnal tides around the shelf break topography (Gunnerus Bank), the results suggest an intricate mechanism in which topographic waves control the seasonal melt rate variability near the grounding line. This mechanism has not been considered before and has the potential to enhance local melt rates without advecting different water masses. As topographic waves seem to strengthen in a stratified ocean, the freshening of Antarctic surface water, predicted by observations and models, is likely to increase future basal melting in this area. Plain Language Summary Ice shelves (or the floating parts of the Antarctic ice sheet) lose primarily mass through melting at their bottom in contact with the ocean. This thins them and makes them more vulnerable to potential collapse. To understand the processes governing such thinning, direct and long-time measurements are essential. Here we report on the first high-resolution time series of direct melt measurements on the Roi Baudouin Ice Shelf in Dronning Maud Land during 2016. We find that subshelf melt varies on both seasonal and daily time scales. Temporal variations stem from topographical ocean waves that originate on the continental shelf and transfer ocean properties without time delay within the ice shelf cavity. Therefore, seasonal variations highly depend on the presence/absence of sea ice in front of the ice shelf, which impact the strength of topographical waves. This mechanism is highly efficient at increasing the ice-ocean exchanges and may explain regional differences in ice shelf melt. |
format |
Article in Journal/Newspaper |
author |
Sun, Sainan Hattermann, Tore Pattyn, Frank Nicholls, Keith W. Drews, Reinhard Berger, Sophie |
spellingShingle |
Sun, Sainan Hattermann, Tore Pattyn, Frank Nicholls, Keith W. Drews, Reinhard Berger, Sophie Topographic shelf waves control seasonal melting near Antarctic Ice Shelf grounding lines |
author_facet |
Sun, Sainan Hattermann, Tore Pattyn, Frank Nicholls, Keith W. Drews, Reinhard Berger, Sophie |
author_sort |
Sun, Sainan |
title |
Topographic shelf waves control seasonal melting near Antarctic Ice Shelf grounding lines |
title_short |
Topographic shelf waves control seasonal melting near Antarctic Ice Shelf grounding lines |
title_full |
Topographic shelf waves control seasonal melting near Antarctic Ice Shelf grounding lines |
title_fullStr |
Topographic shelf waves control seasonal melting near Antarctic Ice Shelf grounding lines |
title_full_unstemmed |
Topographic shelf waves control seasonal melting near Antarctic Ice Shelf grounding lines |
title_sort |
topographic shelf waves control seasonal melting near antarctic ice shelf grounding lines |
publisher |
American Geophysical Union |
publishDate |
2019 |
url |
http://nora.nerc.ac.uk/id/eprint/525689/ https://nora.nerc.ac.uk/id/eprint/525689/1/2019GL083881.pdf https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083881 |
long_lat |
ENVELOPE(24.461,24.461,-70.438,-70.438) ENVELOPE(33.000,33.000,-68.000,-68.000) |
geographic |
Antarctic The Antarctic East Antarctica Dronning Maud Land Roi Baudouin Gunnerus Bank |
geographic_facet |
Antarctic The Antarctic East Antarctica Dronning Maud Land Roi Baudouin Gunnerus Bank |
genre |
Antarc* Antarctic Antarctica Dronning Maud Land East Antarctica Ice Sheet Ice Shelf Ice Shelves Sea ice |
genre_facet |
Antarc* Antarctic Antarctica Dronning Maud Land East Antarctica Ice Sheet Ice Shelf Ice Shelves Sea ice |
op_relation |
https://nora.nerc.ac.uk/id/eprint/525689/1/2019GL083881.pdf Sun, Sainan; Hattermann, Tore; Pattyn, Frank; Nicholls, Keith W. orcid:0000-0002-2188-4509 Drews, Reinhard; Berger, Sophie. 2019 Topographic shelf waves control seasonal melting near Antarctic Ice Shelf grounding lines. Geophysical Research Letters, 46 (16). 9824-9832. https://doi.org/10.1029/2019GL083881 <https://doi.org/10.1029/2019GL083881> |
op_doi |
https://doi.org/10.1029/2019GL083881 |
container_title |
Geophysical Research Letters |
container_volume |
46 |
container_issue |
16 |
container_start_page |
9824 |
op_container_end_page |
9832 |
_version_ |
1766156157311778816 |