Evidence for increased expression of the Amundsen Sea Low over the South Atlantic during the late Holocene

<p>The Amundsen Sea Low (ASL) plays a major role in the climate and environment of Antarctica and the Southern Ocean, including surface air temperature and sea ice concentration changes. Unfortunately, a relative dearth of observational data across the Amundsen and Bellingshausen seas prior...

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Main Authors:	Z. A. Thomas, R. T. Jones, C. J. Fogwill, J. Hatton, A. N. Williams, A. Hogg, S. Mooney, P. Jones, D. Lister, P. Mayewski, C. S. M. Turney
Format:	Article
Language:	English
Published:	Copernicus Publications 2018-11-01
Series:	Climate of the Past
Online Access:	https://www.clim-past.net/14/1727/2018/cp-14-1727-2018.pdf

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record_format	Article
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language	English
format	Article
sources	DOAJ
author	Z. A. Thomas Z. A. Thomas Z. A. Thomas R. T. Jones R. T. Jones C. J. Fogwill C. J. Fogwill C. J. Fogwill J. Hatton A. N. Williams A. N. Williams A. N. Williams A. Hogg S. Mooney P. Jones D. Lister P. Mayewski C. S. M. Turney C. S. M. Turney C. S. M. Turney
spellingShingle	Z. A. Thomas Z. A. Thomas Z. A. Thomas R. T. Jones R. T. Jones C. J. Fogwill C. J. Fogwill C. J. Fogwill J. Hatton A. N. Williams A. N. Williams A. N. Williams A. Hogg S. Mooney P. Jones D. Lister P. Mayewski C. S. M. Turney C. S. M. Turney C. S. M. Turney Evidence for increased expression of the Amundsen Sea Low over the South Atlantic during the late Holocene Climate of the Past
author_facet	Z. A. Thomas Z. A. Thomas Z. A. Thomas R. T. Jones R. T. Jones C. J. Fogwill C. J. Fogwill C. J. Fogwill J. Hatton A. N. Williams A. N. Williams A. N. Williams A. Hogg S. Mooney P. Jones D. Lister P. Mayewski C. S. M. Turney C. S. M. Turney C. S. M. Turney
author_sort	Z. A. Thomas
title	Evidence for increased expression of the Amundsen Sea Low over the South Atlantic during the late Holocene
title_short	Evidence for increased expression of the Amundsen Sea Low over the South Atlantic during the late Holocene
title_full	Evidence for increased expression of the Amundsen Sea Low over the South Atlantic during the late Holocene
title_fullStr	Evidence for increased expression of the Amundsen Sea Low over the South Atlantic during the late Holocene
title_full_unstemmed	Evidence for increased expression of the Amundsen Sea Low over the South Atlantic during the late Holocene
title_sort	evidence for increased expression of the amundsen sea low over the south atlantic during the late holocene
publisher	Copernicus Publications
series	Climate of the Past
issn	1814-9324 1814-9332
publishDate	2018-11-01
description	<p>The Amundsen Sea Low (ASL) plays a major role in the climate and environment of Antarctica and the Southern Ocean, including surface air temperature and sea ice concentration changes. Unfortunately, a relative dearth of observational data across the Amundsen and Bellingshausen seas prior to the satellite era (post-1979) limits our understanding of the past behaviour and impact of the ASL. The limited proxy evidence for changes in the ASL are primarily restricted to the Antarctic where ice core evidence suggests a deepening of the atmospheric pressure system during the late Holocene. However, no data have previously been reported from the northern side of the ASL. Here we report a high-resolution, multi-proxy study of a 5000-year-long peat record from the Falkland Islands, a location sensitive to contemporary ASL dynamics which modulates northerly and westerly airflow across the southwestern South Atlantic sector of the Southern Ocean. In combination with climate reanalysis, we find a marked period of wetter, colder conditions most likely the result of enhanced southerly airflow between 5000 and 2500 years ago, suggesting limited ASL influence over the region. After 2500 years ago, drier and warmer conditions were established, implying more westerly airflow and the increased projection of the ASL onto the South Atlantic. The possible role of the equatorial Pacific via atmospheric teleconnections in driving this change is discussed. Our results are in agreement with Antarctic ice core records and fjord sediments from the southern South American coast, and suggest that the Falkland Islands provide a valuable location for reconstructing high southern latitude atmospheric circulation changes on multi-decadal to millennial timescales.</p>
url	https://www.clim-past.net/14/1727/2018/cp-14-1727-2018.pdf
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spelling	doaj-34701848b44b45989f01430466abb42a2020-11-25T02:24:35ZengCopernicus PublicationsClimate of the Past1814-93241814-93322018-11-011417271738Evidence for increased expression of the Amundsen Sea Low over the South Atlantic during the late HoloceneZ. A. Thomas0Z. A. Thomas1Z. A. Thomas2R. T. Jones3R. T. Jones4C. J. Fogwill5C. J. Fogwill6C. J. Fogwill7J. Hatton8A. N. Williams9A. N. Williams10A. N. Williams11A. Hogg12S. Mooney13P. Jones14D. Lister15P. Mayewski16C. S. M. Turney17C. S. M. Turney18C. S. M. Turney19Palaeontology, Geobiology and Earth Archives Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, AustraliaClimate Change Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, AustraliaARC Centre of Excellence in Australian Biodiversity and Heritage (CABAH), School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australiaformerly at: Department of Geography, Exeter University, Devon, EX4 4RJ, UKdeceasedPalaeontology, Geobiology and Earth Archives Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, AustraliaClimate Change Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, AustraliaSchool of Geography, Geology and the Environment, Keele University, Staffordshire, ST5 5BG, UKDepartment of Geography, Exeter University, Devon, EX4 4RJ, UKClimate Change Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, AustraliaARC Centre of Excellence in Australian Biodiversity and Heritage (CABAH), School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, AustraliaExtent Heritage Pty Ltd, 3/73 Union Street, Pyrmont, NSW 2009, AustraliaWaikato Radiocarbon Dating Laboratory, University of Waikato, Private Bag 3105, Hamilton, New ZealandPalaeontology, Geobiology and Earth Archives Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, AustraliaClimatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich, UKClimatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich, UKClimate Change Institute, University of Maine, Orono, ME, USAPalaeontology, Geobiology and Earth Archives Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, AustraliaClimate Change Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, AustraliaARC Centre of Excellence in Australian Biodiversity and Heritage (CABAH), School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia<p>The Amundsen Sea Low (ASL) plays a major role in the climate and environment of Antarctica and the Southern Ocean, including surface air temperature and sea ice concentration changes. Unfortunately, a relative dearth of observational data across the Amundsen and Bellingshausen seas prior to the satellite era (post-1979) limits our understanding of the past behaviour and impact of the ASL. The limited proxy evidence for changes in the ASL are primarily restricted to the Antarctic where ice core evidence suggests a deepening of the atmospheric pressure system during the late Holocene. However, no data have previously been reported from the northern side of the ASL. Here we report a high-resolution, multi-proxy study of a 5000-year-long peat record from the Falkland Islands, a location sensitive to contemporary ASL dynamics which modulates northerly and westerly airflow across the southwestern South Atlantic sector of the Southern Ocean. In combination with climate reanalysis, we find a marked period of wetter, colder conditions most likely the result of enhanced southerly airflow between 5000 and 2500 years ago, suggesting limited ASL influence over the region. After 2500 years ago, drier and warmer conditions were established, implying more westerly airflow and the increased projection of the ASL onto the South Atlantic. The possible role of the equatorial Pacific via atmospheric teleconnections in driving this change is discussed. Our results are in agreement with Antarctic ice core records and fjord sediments from the southern South American coast, and suggest that the Falkland Islands provide a valuable location for reconstructing high southern latitude atmospheric circulation changes on multi-decadal to millennial timescales.</p>https://www.clim-past.net/14/1727/2018/cp-14-1727-2018.pdf

Evidence for increased expression of the Amundsen Sea Low over the South Atlantic during the late Holocene

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