Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/cp-2018-11
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
01 Mar 2018
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Climate of the Past (CP).
Evidence for increased expression of the Amundsen Sea Low over the South Atlantic during the late Holocene
Zoë Thomas1,2,3, Richard T. Jones4,†, Chris Fogwill1,2,5, Jackie Hatton4, Alan Williams2,3,6, Alan Hogg7, Scott Mooney1, Philip Jones8,9, David Lister8, Paul Mayewski10, and Chris Turney1,2,3 1Palaeontology, Geobiology and Earth Archives Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Australia
2Climate Change Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Australia
3ARC Centre of Excellence in Australian Biodiversity and Heritage (CABAH), School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
4Department of Geography, Exeter University, Devon, EX4 4RJ, UK
5School of Geography, Geology and the Environment , Keele University, Staffordshire, ST5 5BG, UK
6College of Humanities, Arts & Social Sciences, Flinders University, Bedford Park, SA 5042, Australia
7Waikato Radiocarbon Laboratory, University of Waikato, Private Bag 3105, Hamilton, New Zealand
8Climatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich, UK
9Center of Excellence for Climate Change Research, Department of Meteorology, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
10Climate Change Institute, University of Maine, Orono, ME, USA
deceased
Abstract. The Amundsen Sea Low (ASL) plays a major role in modulating the climate and environment of Antarctica and is of global importance in the Earth system. Unfortunately, a relative dearth of observational data across the Amundsen and Bellingshausen Seas prior to the satellite era (post-1979) limits our understanding of past behaviour and impact of the ASL. The limited proxy evidence for changes in the ASL are primarily limited to the Antarctic where ice core evidence suggests a deepening of the atmospheric pressure system during the late Holocene. However, no data has 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 (South Atlantic sector of the Southern Ocean), an area sensitive to contemporary ASL dynamics. 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, and inconsistent with synoptic conditions associated with the ASL today. 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. Our results are in agreement with Antarctic ice core records and suggest the Falkland Islands provide a valuable location for reconstructing atmospheric circulation changes across a large sector of the Southern Ocean on multi-decadal to millennial timescales. The possible role of tropical Pacific in establishing contemporary-like synoptic circulation is explored.
Citation: Thomas, Z., Jones, R. T., Fogwill, C., Hatton, J., Williams, A., Hogg, A., Mooney, S., Jones, P., Lister, D., Mayewski, P., and Turney, C.: Evidence for increased expression of the Amundsen Sea Low over the South Atlantic during the late Holocene, Clim. Past Discuss., https://doi.org/10.5194/cp-2018-11, in review, 2018.
Zoë Thomas et al.
Zoë Thomas et al.
Zoë Thomas et al.

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We report a high-resolution study of a 5000 year-long peat record from the Falkland Islands, an area sensitive to the dynamics of the Amundsen Sea Low, which plays a major role in modulating the Southern Ocean climate. We find wetter, colder conditions between 5000 and 2500 years ago due to enhanced southerly airflow, with the establishment of drier and warmer conditions from 2500 years to present, implying more westerly airflow and increased projection of the ASL onto the South Atlantic.
We report a high-resolution study of a 5000 year-long peat record from the Falkland Islands, an...
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