Formation of pedestalled, relict lakes on the McMurdo Ice Shelf, Antarctica
ABSTRACT Surface debris covers much of the western portion of the McMurdo Ice Shelf and has a strong influence on the local surface albedo and energy balance. Differential ablation between debris-covered and debris-free areas creates an unusual heterogeneous surface of topographically low, high-abla...
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crcambridgeupr:10.1017/jog.2019.17 2024-03-03T08:38:59+00:00 Formation of pedestalled, relict lakes on the McMurdo Ice Shelf, Antarctica MACDONALD, GRANT J. BANWELL, ALISON F. WILLIS, IAN C. MAYER, DAVID P. GOODSELL, BECKY MacAYEAL, DOUGLAS R. 2019 http://dx.doi.org/10.1017/jog.2019.17 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143019000170 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 65, issue 250, page 337-343 ISSN 0022-1430 1727-5652 Earth-Surface Processes journal-article 2019 crcambridgeupr https://doi.org/10.1017/jog.2019.17 2024-02-08T08:28:37Z ABSTRACT Surface debris covers much of the western portion of the McMurdo Ice Shelf and has a strong influence on the local surface albedo and energy balance. Differential ablation between debris-covered and debris-free areas creates an unusual heterogeneous surface of topographically low, high-ablation, and topographically raised (‘pedestalled’), low-ablation areas. Analysis of Landsat and MODIS satellite imagery from 1999 to 2018, alongside field observations from the 2016/2017 austral summer, shows that pedestalled relict lakes (‘pedestals’) form when an active surface meltwater lake that develops in the summer, freezes-over in winter, resulting in the lake-bottom debris being masked by a high-albedo, superimposed, ice surface. If this ice surface fails to melt during a subsequent melt season, it experiences reduced surface ablation relative to the surrounding debris-covered areas of the ice shelf. We propose that this differential ablation, and resultant hydrostatic and flexural readjustments of the ice shelf, causes the former supraglacial lake surface to become increasingly pedestalled above the lower topography of the surrounding ice shelf. Consequently, meltwater streams cannot flow onto these pedestalled features, and instead divert around them. We suggest that the development of pedestals has a significant influence on the surface-energy balance, hydrology and flexure of the ice shelf. Article in Journal/Newspaper Antarc* Antarctica Ice Shelf Journal of Glaciology McMurdo Ice Shelf Cambridge University Press Austral McMurdo Ice Shelf ENVELOPE(166.500,166.500,-78.000,-78.000) Journal of Glaciology 65 250 337 343 |
institution |
Open Polar |
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Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
Earth-Surface Processes |
spellingShingle |
Earth-Surface Processes MACDONALD, GRANT J. BANWELL, ALISON F. WILLIS, IAN C. MAYER, DAVID P. GOODSELL, BECKY MacAYEAL, DOUGLAS R. Formation of pedestalled, relict lakes on the McMurdo Ice Shelf, Antarctica |
topic_facet |
Earth-Surface Processes |
description |
ABSTRACT Surface debris covers much of the western portion of the McMurdo Ice Shelf and has a strong influence on the local surface albedo and energy balance. Differential ablation between debris-covered and debris-free areas creates an unusual heterogeneous surface of topographically low, high-ablation, and topographically raised (‘pedestalled’), low-ablation areas. Analysis of Landsat and MODIS satellite imagery from 1999 to 2018, alongside field observations from the 2016/2017 austral summer, shows that pedestalled relict lakes (‘pedestals’) form when an active surface meltwater lake that develops in the summer, freezes-over in winter, resulting in the lake-bottom debris being masked by a high-albedo, superimposed, ice surface. If this ice surface fails to melt during a subsequent melt season, it experiences reduced surface ablation relative to the surrounding debris-covered areas of the ice shelf. We propose that this differential ablation, and resultant hydrostatic and flexural readjustments of the ice shelf, causes the former supraglacial lake surface to become increasingly pedestalled above the lower topography of the surrounding ice shelf. Consequently, meltwater streams cannot flow onto these pedestalled features, and instead divert around them. We suggest that the development of pedestals has a significant influence on the surface-energy balance, hydrology and flexure of the ice shelf. |
format |
Article in Journal/Newspaper |
author |
MACDONALD, GRANT J. BANWELL, ALISON F. WILLIS, IAN C. MAYER, DAVID P. GOODSELL, BECKY MacAYEAL, DOUGLAS R. |
author_facet |
MACDONALD, GRANT J. BANWELL, ALISON F. WILLIS, IAN C. MAYER, DAVID P. GOODSELL, BECKY MacAYEAL, DOUGLAS R. |
author_sort |
MACDONALD, GRANT J. |
title |
Formation of pedestalled, relict lakes on the McMurdo Ice Shelf, Antarctica |
title_short |
Formation of pedestalled, relict lakes on the McMurdo Ice Shelf, Antarctica |
title_full |
Formation of pedestalled, relict lakes on the McMurdo Ice Shelf, Antarctica |
title_fullStr |
Formation of pedestalled, relict lakes on the McMurdo Ice Shelf, Antarctica |
title_full_unstemmed |
Formation of pedestalled, relict lakes on the McMurdo Ice Shelf, Antarctica |
title_sort |
formation of pedestalled, relict lakes on the mcmurdo ice shelf, antarctica |
publisher |
Cambridge University Press (CUP) |
publishDate |
2019 |
url |
http://dx.doi.org/10.1017/jog.2019.17 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143019000170 |
long_lat |
ENVELOPE(166.500,166.500,-78.000,-78.000) |
geographic |
Austral McMurdo Ice Shelf |
geographic_facet |
Austral McMurdo Ice Shelf |
genre |
Antarc* Antarctica Ice Shelf Journal of Glaciology McMurdo Ice Shelf |
genre_facet |
Antarc* Antarctica Ice Shelf Journal of Glaciology McMurdo Ice Shelf |
op_source |
Journal of Glaciology volume 65, issue 250, page 337-343 ISSN 0022-1430 1727-5652 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2019.17 |
container_title |
Journal of Glaciology |
container_volume |
65 |
container_issue |
250 |
container_start_page |
337 |
op_container_end_page |
343 |
_version_ |
1792494387094093824 |