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

Thomas, ZA; Jones, RT; Fogwill, CJ; Hatton, J; Williams, AN; Hogg, A; Mooney, S; Jones, P; Lister, D; Mayewski, P; Turney, CSM

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

Thomas, ZA Jones, RT Fogwill, CJ Hatton, J Williams, AN Hogg, A Mooney, S Jones, P Lister, D Mayewski, P Turney, CSM

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Publisher:: Copernicus GmbH
Publication Type:: Journal Article
Citation:: Climate of the Past, 2018, 14, (11), pp. 1727-1738
Issue Date:: 2018-11-13

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Field	Value	Language
dc.contributor.author	Thomas, ZA
dc.contributor.author	Jones, RT
dc.contributor.author	Fogwill, CJ
dc.contributor.author	Hatton, J
dc.contributor.author	Williams, AN
dc.contributor.author	Hogg, A
dc.contributor.author	Mooney, S
dc.contributor.author	Jones, P
dc.contributor.author	Lister, D
dc.contributor.author	Mayewski, P
dc.contributor.author	Turney, CSM
dc.date.accessioned	2022-09-09T23:14:04Z
dc.date.available	2022-09-09T23:14:04Z
dc.date.issued	2018-11-13
dc.identifier.citation	Climate of the Past, 2018, 14, (11), pp. 1727-1738
dc.identifier.issn	1814-9324
dc.identifier.issn	1814-9332
dc.identifier.uri	http://hdl.handle.net/10453/161601
dc.description.abstract	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.
dc.language	en
dc.publisher	Copernicus GmbH
dc.relation	http://purl.org/au-research/grants/arc/FL100100195
dc.relation	http://purl.org/au-research/grants/arc/DP130104156
dc.relation.ispartof	Climate of the Past
dc.relation.isbasedon	10.5194/cp-14-1727-2018
dc.rights	info:eu-repo/semantics/openAccess
dc.subject	0406 Physical Geography and Environmental Geoscience
dc.subject.classification	Paleontology
dc.title	Evidence for increased expression of the Amundsen Sea Low over the South Atlantic during the late Holocene
dc.type	Journal Article
utslib.citation.volume	14
utslib.for	0406 Physical Geography and Environmental Geoscience
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/DVC (Research)
utslib.copyright.status	open_access	*
dc.date.updated	2022-09-09T23:13:57Z
pubs.issue	11
pubs.publication-status	Published
pubs.volume	14
utslib.citation.issue	11

Abstract:

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.

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http://hdl.handle.net/10453/161601