Enhanced Glacial Discharge from the Eastern Antarctic Peninsula since the 1700s Associated with a Positive Southern Annular Mode
The Antarctic Peninsula Ice Sheet is currently experiencing sustained and accelerating loss of ice. Determining when these changes were initiated and identifying the main drivers is hampered by the short instrumental record (1992 to present). Here we present a 6,250 year record of glacial discharge...
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ftunisfloridatam:oai:digitalcommons.usf.edu:msc_facpub-2533 2023-05-15T14:04:11+02:00 Enhanced Glacial Discharge from the Eastern Antarctic Peninsula since the 1700s Associated with a Positive Southern Annular Mode Dickens, W. A. Kuhn, G. Leng, M. J. Graham, Alastair G. C. Dowdeswell, J. A. Meredith, M. P. Hillenbrand, C.-D. Hodgson, D. A. Roberts, S. J. Sloane, H. Smith, J. A. 2019-01-01T08:00:00Z application/pdf https://digitalcommons.usf.edu/msc_facpub/1580 https://digitalcommons.usf.edu/cgi/viewcontent.cgi?article=2533&context=msc_facpub unknown Digital Commons @ University of South Florida https://digitalcommons.usf.edu/msc_facpub/1580 https://digitalcommons.usf.edu/cgi/viewcontent.cgi?article=2533&context=msc_facpub http://creativecommons.org/licenses/by/4.0/ CC-BY Marine Science Faculty Publications Cryospheric science Palaeoclimate Life Sciences article 2019 ftunisfloridatam 2022-01-20T18:39:31Z The Antarctic Peninsula Ice Sheet is currently experiencing sustained and accelerating loss of ice. Determining when these changes were initiated and identifying the main drivers is hampered by the short instrumental record (1992 to present). Here we present a 6,250 year record of glacial discharge based on the oxygen isotope composition of diatoms (δ18Odiatom) from a marine core located at the north-eastern tip of the Antarctic Peninsula. We find that glacial discharge - sourced primarily from ice shelf and iceberg melting along the eastern Antarctic Peninsula – remained largely stable between ~6,250 to 1,620 cal. yr BP, with a slight increase in variability until ~720 cal. yr. BP. An increasing trend in glacial discharge occurs after 550 cal. yr BP (A.D. 1400), reaching levels unprecedented during the past 6,250 years after 244 cal. yr BP (A.D. 1706). A marked acceleration in the rate of glacial discharge is also observed in the early part of twentieth century (after A.D. 1912). Enhanced glacial discharge, particularly after the 1700s is linked to a positive Southern Annular Mode (SAM). We argue that a positive SAM drove stronger westerly winds, atmospheric warming and surface ablation on the eastern Antarctic Peninsula whilst simultaneously entraining more warm water into the Weddell Gyre, potentially increasing melting on the undersides of ice shelves. A possible implication of our data is that ice shelves in this region have been thinning for at least ~300 years, potentially predisposing them to collapse under intensified anthropogenic warming. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Ice Sheet Ice Shelf Ice Shelves Iceberg* Digital Commons University of South Florida (USF) Antarctic The Antarctic Antarctic Peninsula Weddell |
institution |
Open Polar |
collection |
Digital Commons University of South Florida (USF) |
op_collection_id |
ftunisfloridatam |
language |
unknown |
topic |
Cryospheric science Palaeoclimate Life Sciences |
spellingShingle |
Cryospheric science Palaeoclimate Life Sciences Dickens, W. A. Kuhn, G. Leng, M. J. Graham, Alastair G. C. Dowdeswell, J. A. Meredith, M. P. Hillenbrand, C.-D. Hodgson, D. A. Roberts, S. J. Sloane, H. Smith, J. A. Enhanced Glacial Discharge from the Eastern Antarctic Peninsula since the 1700s Associated with a Positive Southern Annular Mode |
topic_facet |
Cryospheric science Palaeoclimate Life Sciences |
description |
The Antarctic Peninsula Ice Sheet is currently experiencing sustained and accelerating loss of ice. Determining when these changes were initiated and identifying the main drivers is hampered by the short instrumental record (1992 to present). Here we present a 6,250 year record of glacial discharge based on the oxygen isotope composition of diatoms (δ18Odiatom) from a marine core located at the north-eastern tip of the Antarctic Peninsula. We find that glacial discharge - sourced primarily from ice shelf and iceberg melting along the eastern Antarctic Peninsula – remained largely stable between ~6,250 to 1,620 cal. yr BP, with a slight increase in variability until ~720 cal. yr. BP. An increasing trend in glacial discharge occurs after 550 cal. yr BP (A.D. 1400), reaching levels unprecedented during the past 6,250 years after 244 cal. yr BP (A.D. 1706). A marked acceleration in the rate of glacial discharge is also observed in the early part of twentieth century (after A.D. 1912). Enhanced glacial discharge, particularly after the 1700s is linked to a positive Southern Annular Mode (SAM). We argue that a positive SAM drove stronger westerly winds, atmospheric warming and surface ablation on the eastern Antarctic Peninsula whilst simultaneously entraining more warm water into the Weddell Gyre, potentially increasing melting on the undersides of ice shelves. A possible implication of our data is that ice shelves in this region have been thinning for at least ~300 years, potentially predisposing them to collapse under intensified anthropogenic warming. |
format |
Article in Journal/Newspaper |
author |
Dickens, W. A. Kuhn, G. Leng, M. J. Graham, Alastair G. C. Dowdeswell, J. A. Meredith, M. P. Hillenbrand, C.-D. Hodgson, D. A. Roberts, S. J. Sloane, H. Smith, J. A. |
author_facet |
Dickens, W. A. Kuhn, G. Leng, M. J. Graham, Alastair G. C. Dowdeswell, J. A. Meredith, M. P. Hillenbrand, C.-D. Hodgson, D. A. Roberts, S. J. Sloane, H. Smith, J. A. |
author_sort |
Dickens, W. A. |
title |
Enhanced Glacial Discharge from the Eastern Antarctic Peninsula since the 1700s Associated with a Positive Southern Annular Mode |
title_short |
Enhanced Glacial Discharge from the Eastern Antarctic Peninsula since the 1700s Associated with a Positive Southern Annular Mode |
title_full |
Enhanced Glacial Discharge from the Eastern Antarctic Peninsula since the 1700s Associated with a Positive Southern Annular Mode |
title_fullStr |
Enhanced Glacial Discharge from the Eastern Antarctic Peninsula since the 1700s Associated with a Positive Southern Annular Mode |
title_full_unstemmed |
Enhanced Glacial Discharge from the Eastern Antarctic Peninsula since the 1700s Associated with a Positive Southern Annular Mode |
title_sort |
enhanced glacial discharge from the eastern antarctic peninsula since the 1700s associated with a positive southern annular mode |
publisher |
Digital Commons @ University of South Florida |
publishDate |
2019 |
url |
https://digitalcommons.usf.edu/msc_facpub/1580 https://digitalcommons.usf.edu/cgi/viewcontent.cgi?article=2533&context=msc_facpub |
geographic |
Antarctic The Antarctic Antarctic Peninsula Weddell |
geographic_facet |
Antarctic The Antarctic Antarctic Peninsula Weddell |
genre |
Antarc* Antarctic Antarctic Peninsula Ice Sheet Ice Shelf Ice Shelves Iceberg* |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Ice Sheet Ice Shelf Ice Shelves Iceberg* |
op_source |
Marine Science Faculty Publications |
op_relation |
https://digitalcommons.usf.edu/msc_facpub/1580 https://digitalcommons.usf.edu/cgi/viewcontent.cgi?article=2533&context=msc_facpub |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_rightsnorm |
CC-BY |
_version_ |
1766275204183490560 |