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High resolution reconstructions of climate variability in the sub-Antarctic during the last two millennia

English title High resolution reconstructions of climate variability in the sub-Antarctic during the last two millennia
Applicant Saunders Krystyna
Number 136835
Funding scheme Ambizione
Research institution Geographisches Institut Universität Bern
Institution of higher education University of Berne - BE
Main discipline Hydrology, Limnology, Glaciology
Start/End 01.01.2012 - 31.05.2015
Approved amount 521'222.00
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Keywords (6)

sub-Antarctic; Southern Hemisphere; Palaeolimnology; Palaeoclimate; High resolution; Westerly winds

Lay Summary (English)

Lead
Lay summary

Our understanding of present global climate and the ability to predict future changes are limited by the comparative lack of data from the Southern Hemisphere. The mid to high latitudes of the Hemisphere are dominated by the westerly winds. These are important because changes in their strength determine precipitation and temperature regimes in this region. They are also a key factor influencing global carbon dioxide flux because the winds control the upwelling of deep ocean water rich in carbon, which in turn is exchanged with the atmosphere. 

Despite their importance to both Southern Hemisphere and global climates, little is known about how the westerly winds changed in the past. Several key questions remain:

1. What is the past variability in the strength of the westerly winds and how do they influence precipitation and temperature in the Southern Hemisphere and the carbon dioxide sink in the Southern Ocean?

2. How comparable is the pattern of change in the winds between different regions of the sub-Antarctic, Antarctica, mid latitudes of the Southern and the Northern Hemispheres?

3. Are changes in the 20th century of similar rate and magnitude to other periods in the last 2000 years?

 The proposed project aims to address these questions by developing and applying lake sediment-based proxies for changes in wind strength, temperature and/or precipitation at three sub-Antarctic islands (Campbell, Macquarie and Marion Islands) in order to develop 2000-year long climate reconstructions. Sub-Antarctic islands are the only landmasses between Antarctica and the southern extremities of South America, Africa and Australia where terrestrial climate records are available, making them crucial locations for linking southern mid- and high-latitude climate data.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Development of a regional Glycerol Dialkyl Glycerol Tetraether (GDGT) temperature calibration for Antarctic and sub-Antarctic lakes
Foster Louise (2016), Development of a regional Glycerol Dialkyl Glycerol Tetraether (GDGT) temperature calibration for Antarctic and sub-Antarctic lakes, in Earth and Planetary Science Letters, 433, 370-379.
A diatom–conductivity transfer function for reconstructing past changes in the Southern Hemisphere westerly winds over the Southern Ocean
Saunders Krystyna, Hodgson Dominic, McMurtrie Shelley, Grosjean, Martin (2015), A diatom–conductivity transfer function for reconstructing past changes in the Southern Hemisphere westerly winds over the Southern Ocean, in Journal of Quaternary Science, 30(5), 464-477.

Collaboration

Group / person Country
Types of collaboration
50 degrees South Trust New Zealand (Oceania)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Ice core group, Australian Antarctic Division Australia (Oceania)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Quaternary sediments group, British Antarctic Survey Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Palaeoenvironmental research group, University of Melbourne Australia (Oceania)
- in-depth/constructive exchanges on approaches, methods or results
THE LAST GLACIAL MAXIMUM IN THE SOUTHERN HEMISPHERE (SHeMax) PROJECT Australia (Oceania)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
National Institute of Water and the Atmosphere New Zealand (Oceania)
- in-depth/constructive exchanges on approaches, methods or results
Australasia 2K, IGBP-PAGES Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
4th Australasia 2k workshop (Past Global Changes network) Poster High-resolution Southern Hemisphere westerly wind reconstructions using sub-Antarctic lake sediments: an example from Macquarie Island (54°S) 27.10.2015 Auckland, New Zealand Saunders Krystyna;
European Geosciences Union General Assembly Poster Southern Hemisphere westerly wind strength at sub-Antarctic Macquarie Island since the end of the Last Glacial Maximum 27.04.2014 Vienna, Austria Saunders Krystyna;
Australian Meteorological and Oceanographic Society Talk given at a conference Southern Hemisphere westerly wind strength since the Last Glacial Maximum 12.02.2014 Hobart, Tasmania, Australia Saunders Krystyna;
Southern Hemisphere Assessment of PalaeoEnvironment workshop Individual talk A Southern Hemisphere westerly wind reconstruction from sub-Antarctic Macquarie Island 28.01.2014 Auckland, New Zealand Saunders Krystyna;
International Paleolimnology Symposium Poster A 950 year temperature reconstruction from Duckhole Lake, southeast Tasmania, Australia 20.08.2013 University of Glasgow, Great Britain and Northern Ireland Saunders Krystyna;
Southern Connections Poster Multi-decadal precipitation and westerly wind variability in the mid and high latitudes of the Southern Hemisphere over the last 1000 years 21.01.2013 University of Otago, Otago, New Zealand Saunders Krystyna;
Southern Connections Talk given at a conference Last Glacial and Holocene westerly wind changes on sub-Antarctic Macquarie Island 21.01.2013 University of Otago, Otago, New Zealand Saunders Krystyna;
International Paleolimnology Symposium, University of Glasgow Talk given at a conference Holocene westerly wind and ecosystem changes on sub-Antarctic Macquarie Island 20.08.2012 University of Glasgow, Great Britain and Northern Ireland Saunders Krystyna;
Scientific Committee on Antarctic Research Open Science Meeting, University of Portland Poster 12,000 years of westerly wind and ecosystem changes on sub-Antarctic Macquarie Island 15.07.2012 University of Portland, USA, United States of America Saunders Krystyna;


Knowledge transfer events

Active participation

Title Type of contribution Date Place Persons involved
13th Young Researchs Meeting 2014 "Science and Communication" Workshop 19.06.2014 Aeschi bei Spiez, Switzerland Saunders Krystyna;
Media Workshop Workshop 11.02.2014 Hobart, Tasmania, Australia Saunders Krystyna;
Long View of Climate Change Talk 09.05.2013 University of Bern, Switzerland Saunders Krystyna;


Communication with the public

Communication Title Media Place Year
Video/Film Long View of Climate Change International 2014
New media (web, blogs, podcasts, news feeds etc.) The Far Gone South Overcoat International 2012

Awards

Title Year
Honorary Research Fellow at the University of Tasmania, Australia 2015

Associated projects

Number Title Start Funding scheme
154802 Detection of human and natural influences on the climate system: regional insights from the past Millennium 01.05.2015 Ambizione

Abstract

Our understanding of present global climate and the ability to predict future changes are limited by the comparative lack of data from the Southern Hemisphere. The mid to high latitudes of the Hemisphere are dominated by the westerly winds. These are important because changes in their strengthdetermine precipitation and temperature regimes in this region. They are also a key factor influencing global carbon dioxide flux because the winds control the upwelling of deep ocean water rich in carbon, which in turn is exchanged with the atmosphere. Despite their importance to both SouthernHemisphere and global climates, little is known about how the westerly winds changed in the past.Several key questions remain:• What is the past variability in the strength of the westerly winds and how do they influence precipitation and temperature in the Southern Hemisphere and the carbon dioxide sink in the Southern Ocean?• How comparable is the pattern of change in the winds between different regions of the sub-Antarctic, Antarctica, mid latitudes of the Southern and the Northern Hemispheres?• Are changes in the 20th century of similar rate and magnitude to other periods in the last 2000 years?The proposed project aims to address these questions by developing and applying new lake sediment-based proxies for changes in wind strength, temperature and/or precipitation at three sub-Antarctic islands (Campbell, Macquarie and Marion Islands) in order to develop 2000-year long subdecadally resolved reconstructions. Sub-Antarctic islands are the only landmasses between Antarctica and the southern extremities of South America, Africa and Australia where terrestrial climate records are available, making them crucial locations for linking southern mid- and high-latitude climate data.This approach combines a novel, innovative method for reconstructing wind strength with established proxies for temperature and precipitation. This new method is based on results obtained from limnological studies on Macquarie Island, which identified a marked west-east gradient in the salinity of water bodies across the island as saline ions are delivered by wind-derived sea spray. The salinity gradient determines the diatom communities in the lakes (Saunders et al. 2009). Once this diatomsalinityrelationship is established quantitatively, the sub-fossil diatom communities deposited in dated lake sediment cores can be used to reconstruct changes in salinity through time, and hence past wind strength (Saunders et al. in prep. a). The precipitation and/or temperature reconstructions will bedeveloped from the same sediment cores using scanning in-situ reflectance spectroscopy (380-730 nm, VIS-RS). This technique can, once calibrated, produce high quality, quantitative reconstructions at sub-decadal to annual resolution (e.g. Trachsel et al. 2010; von Gunten et al. 2009a).To develop circum-hemispheric high resolution reconstructions of changes in westerly wind strength, precipitation and/or temperature over the last 2000 years, the records from Campbell, Macquarie and Marion Islands will be integrated with climate records previously developed by the applicant forTasmania and by her collaborators for southern South America and nearby sub-Antarctic islands. In addition, a partner proposal with modeling experts at the British Antarctic Survey will seek funding to run the HADAM Global Climate Model to explore the regional hemispheric and global implications ofthe new data, including effects of carbon dioxide.The proposed project will allow the applicant to: (a) further enhance skills developed as a Marie Curie International Incoming Fellow at the University of Bern; (b) initiate new collaborations, while building on existing ones; and (c) facilitate her development as an independent, high profile researcher in this dynamic and critical field of research. All necessary equipment and support is available at the host institute or through the applicant’s collaborations. This is an independent project that will providesignificant, unique data for a relatively unknown region, which is nevertheless critical for our overall understanding of past climate variability.
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