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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ftdoajarticles:oai:doaj.org/article:ab631df229a94ab08cddddbf102944ef 2023-05-15T13:22:05+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 2021-05-01T00:00:00Z https://doi.org/10.5194/tc-15-2147-2021 https://doaj.org/article/ab631df229a94ab08cddddbf102944ef EN eng Copernicus Publications https://tc.copernicus.org/articles/15/2147/2021/tc-15-2147-2021.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-15-2147-2021 1994-0416 1994-0424 https://doaj.org/article/ab631df229a94ab08cddddbf102944ef The Cryosphere, Vol 15, Pp 2147-2165 (2021) Environmental sciences GE1-350 Geology QE1-996.5 article 2021 ftdoajarticles https://doi.org/10.5194/tc-15-2147-2021 2022-12-31T06:04:56Z 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 Directory of Open Access Journals: DOAJ Articles Antarctic Amery ENVELOPE(-94.063,-94.063,56.565,56.565) Amery Ice Shelf ENVELOPE(71.000,71.000,-69.750,-69.750) The Cryosphere 15 5 2147 2165 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 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 |
Environmental sciences GE1-350 Geology QE1-996.5 |
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://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 |
Antarctic Amery Amery Ice Shelf |
geographic_facet |
Antarctic Amery Amery Ice Shelf |
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 |
https://tc.copernicus.org/articles/15/2147/2021/tc-15-2147-2021.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-15-2147-2021 1994-0416 1994-0424 https://doaj.org/article/ab631df229a94ab08cddddbf102944ef |
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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1766363226631569408 |