Atmospheric extremes caused high oceanward sea surface slope triggering the biggest calving event in more than 50 years at the Amery Ice Shelf
Ice shelf instability is one of the main sources of uncertainty in Antarctica's contribution to future sea level rise. Calving events play a crucial role in ice shelf weakening but remain unpredictable, and their governing processes are still poorly understood. In this study, we analyze the une...
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Copernicus Publications
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Online Access: | https://doi.org/10.5194/tc-15-2147-2021 https://tc.copernicus.org/articles/15/2147/2021/tc-15-2147-2021.pdf https://doaj.org/article/ab631df229a94ab08cddddbf102944ef |
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fttriple:oai:gotriple.eu:oai:doaj.org/article:ab631df229a94ab08cddddbf102944ef 2023-05-15T13:22:04+02:00 Atmospheric extremes caused high oceanward sea surface slope triggering the biggest calving event in more than 50 years at the Amery Ice Shelf D. Francis K. S. Mattingly S. Lhermitte M. Temimi P. Heil 2021-05-01 https://doi.org/10.5194/tc-15-2147-2021 https://tc.copernicus.org/articles/15/2147/2021/tc-15-2147-2021.pdf https://doaj.org/article/ab631df229a94ab08cddddbf102944ef en eng Copernicus Publications doi:10.5194/tc-15-2147-2021 1994-0416 1994-0424 https://tc.copernicus.org/articles/15/2147/2021/tc-15-2147-2021.pdf https://doaj.org/article/ab631df229a94ab08cddddbf102944ef undefined The Cryosphere, Vol 15, Pp 2147-2165 (2021) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2021 fttriple https://doi.org/10.5194/tc-15-2147-2021 2023-01-22T19:27:58Z Ice shelf instability is one of the main sources of uncertainty in Antarctica's contribution to future sea level rise. Calving events play a crucial role in ice shelf weakening but remain unpredictable, and their governing processes are still poorly understood. In this study, we analyze the unexpected September 2019 calving event from the Amery Ice Shelf, the largest since 1963 and which occurred almost a decade earlier than expected, to better understand the role of the atmosphere in calving. We find that atmospheric extremes provided a deterministic role in this event. A series of anomalously deep and stationary explosive twin polar cyclones over the Cooperation and Davis seas generated tides and wind-driven ocean slope, leading to fracture amplification along the pre-existing rift and ultimately calving of the massive iceberg. The calving was triggered by high oceanward sea surface slopes produced by the storms. The observed record-anomalous atmospheric conditions were promoted by blocking ridges and Antarctic-wide anomalous poleward transport of heat and moisture. Blocking highs helped in (i) directing moist and warm air masses towards the ice shelf and (ii) maintaining the observed extreme cyclones stationary at the front of the ice shelf for several days. Accumulation of cold air over the ice sheet, due to the blocking highs, led to the formation of an intense cold high pressure over the ice sheet, which helped fuel sustained anomalously deep cyclones via increased baroclinicity. Our results stress the importance of atmospheric extremes in ice shelf dynamics via tides and sea surface slope and its need to be accounted for when considering Antarctic ice shelf variability and contribution to sea level, especially given that more of these extremes are predicted under a warmer climate. Article in Journal/Newspaper Amery Ice Shelf Antarc* Antarctic Ice Sheet Ice Shelf Iceberg* The Cryosphere Unknown Amery ENVELOPE(-94.063,-94.063,56.565,56.565) Amery Ice Shelf ENVELOPE(71.000,71.000,-69.750,-69.750) Antarctic The Cryosphere 15 5 2147 2165 |
institution |
Open Polar |
collection |
Unknown |
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fttriple |
language |
English |
topic |
geo envir |
spellingShingle |
geo envir D. Francis K. S. Mattingly S. Lhermitte M. Temimi P. Heil Atmospheric extremes caused high oceanward sea surface slope triggering the biggest calving event in more than 50 years at the Amery Ice Shelf |
topic_facet |
geo envir |
description |
Ice shelf instability is one of the main sources of uncertainty in Antarctica's contribution to future sea level rise. Calving events play a crucial role in ice shelf weakening but remain unpredictable, and their governing processes are still poorly understood. In this study, we analyze the unexpected September 2019 calving event from the Amery Ice Shelf, the largest since 1963 and which occurred almost a decade earlier than expected, to better understand the role of the atmosphere in calving. We find that atmospheric extremes provided a deterministic role in this event. A series of anomalously deep and stationary explosive twin polar cyclones over the Cooperation and Davis seas generated tides and wind-driven ocean slope, leading to fracture amplification along the pre-existing rift and ultimately calving of the massive iceberg. The calving was triggered by high oceanward sea surface slopes produced by the storms. The observed record-anomalous atmospheric conditions were promoted by blocking ridges and Antarctic-wide anomalous poleward transport of heat and moisture. Blocking highs helped in (i) directing moist and warm air masses towards the ice shelf and (ii) maintaining the observed extreme cyclones stationary at the front of the ice shelf for several days. Accumulation of cold air over the ice sheet, due to the blocking highs, led to the formation of an intense cold high pressure over the ice sheet, which helped fuel sustained anomalously deep cyclones via increased baroclinicity. Our results stress the importance of atmospheric extremes in ice shelf dynamics via tides and sea surface slope and its need to be accounted for when considering Antarctic ice shelf variability and contribution to sea level, especially given that more of these extremes are predicted under a warmer climate. |
format |
Article in Journal/Newspaper |
author |
D. Francis K. S. Mattingly S. Lhermitte M. Temimi P. Heil |
author_facet |
D. Francis K. S. Mattingly S. Lhermitte M. Temimi P. Heil |
author_sort |
D. Francis |
title |
Atmospheric extremes caused high oceanward sea surface slope triggering the biggest calving event in more than 50 years at the Amery Ice Shelf |
title_short |
Atmospheric extremes caused high oceanward sea surface slope triggering the biggest calving event in more than 50 years at the Amery Ice Shelf |
title_full |
Atmospheric extremes caused high oceanward sea surface slope triggering the biggest calving event in more than 50 years at the Amery Ice Shelf |
title_fullStr |
Atmospheric extremes caused high oceanward sea surface slope triggering the biggest calving event in more than 50 years at the Amery Ice Shelf |
title_full_unstemmed |
Atmospheric extremes caused high oceanward sea surface slope triggering the biggest calving event in more than 50 years at the Amery Ice Shelf |
title_sort |
atmospheric extremes caused high oceanward sea surface slope triggering the biggest calving event in more than 50 years at the amery ice shelf |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-15-2147-2021 https://tc.copernicus.org/articles/15/2147/2021/tc-15-2147-2021.pdf https://doaj.org/article/ab631df229a94ab08cddddbf102944ef |
long_lat |
ENVELOPE(-94.063,-94.063,56.565,56.565) ENVELOPE(71.000,71.000,-69.750,-69.750) |
geographic |
Amery Amery Ice Shelf Antarctic |
geographic_facet |
Amery Amery Ice Shelf Antarctic |
genre |
Amery Ice Shelf Antarc* Antarctic Ice Sheet Ice Shelf Iceberg* The Cryosphere |
genre_facet |
Amery Ice Shelf Antarc* Antarctic Ice Sheet Ice Shelf Iceberg* The Cryosphere |
op_source |
The Cryosphere, Vol 15, Pp 2147-2165 (2021) |
op_relation |
doi:10.5194/tc-15-2147-2021 1994-0416 1994-0424 https://tc.copernicus.org/articles/15/2147/2021/tc-15-2147-2021.pdf https://doaj.org/article/ab631df229a94ab08cddddbf102944ef |
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undefined |
op_doi |
https://doi.org/10.5194/tc-15-2147-2021 |
container_title |
The Cryosphere |
container_volume |
15 |
container_issue |
5 |
container_start_page |
2147 |
op_container_end_page |
2165 |
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