Southern Hemisphere westerly wind changes during the Last Glacial Maximum: model-data comparison
The Southern Hemisphere (SH) westerly winds are thought to be critical to global ocean circulation, productivity, and carbon storage. For example, an equatorward shift in the winds, though its affect on the Southern Ocean circulation, has been suggested as the leading cause for the reduction in atmo...
Published in: | Quaternary Science Reviews |
---|---|
Main Authors: | , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2013
|
Subjects: | |
Online Access: | http://eprints.esc.cam.ac.uk/2831/ http://eprints.esc.cam.ac.uk/2831/1/Kohfeld_et_al._-_2013_-_Southern_Hemisphere_westerly_wind_changes_during_t.pdf http://eprints.esc.cam.ac.uk/2831/2/1-s2.0-S0277379112005215-gr1.jpg http://www.sciencedirect.com/science/article/pii/S0277379112005215 https://doi.org/10.1016/j.quascirev.2012.12.008 |
id |
ftucambridgeesc:oai:eprints.esc.cam.ac.uk:2831 |
---|---|
record_format |
openpolar |
spelling |
ftucambridgeesc:oai:eprints.esc.cam.ac.uk:2831 2023-05-15T18:18:52+02:00 Southern Hemisphere westerly wind changes during the Last Glacial Maximum: model-data comparison Sime, Louise C. Kohfeld, Karen E. Le Quéré, Corinne Wolff, Eric W. de Boer, Agatha M. Graham, Robert M. Bopp, Laurent 2013-03 application/pdf image/jpeg http://eprints.esc.cam.ac.uk/2831/ http://eprints.esc.cam.ac.uk/2831/1/Kohfeld_et_al._-_2013_-_Southern_Hemisphere_westerly_wind_changes_during_t.pdf http://eprints.esc.cam.ac.uk/2831/2/1-s2.0-S0277379112005215-gr1.jpg http://www.sciencedirect.com/science/article/pii/S0277379112005215 https://doi.org/10.1016/j.quascirev.2012.12.008 en eng http://eprints.esc.cam.ac.uk/2831/1/Kohfeld_et_al._-_2013_-_Southern_Hemisphere_westerly_wind_changes_during_t.pdf http://eprints.esc.cam.ac.uk/2831/2/1-s2.0-S0277379112005215-gr1.jpg Sime, Louise C. and Kohfeld, Karen E. and Le Quéré, Corinne and Wolff, Eric W. and de Boer, Agatha M. and Graham, Robert M. and Bopp, Laurent (2013) Southern Hemisphere westerly wind changes during the Last Glacial Maximum: model-data comparison. Quaternary Science Reviews, 64. pp. 104-120. ISSN 0277-3791 DOI https://doi.org/10.1016/j.quascirev.2012.12.008 <https://doi.org/10.1016/j.quascirev.2012.12.008> 01 - Climate Change and Earth-Ocean Atmosphere Systems Article PeerReviewed 2013 ftucambridgeesc https://doi.org/10.1016/j.quascirev.2012.12.008 2020-08-27T18:09:24Z The Southern Hemisphere (SH) westerly winds are thought to be critical to global ocean circulation, productivity, and carbon storage. For example, an equatorward shift in the winds, though its affect on the Southern Ocean circulation, has been suggested as the leading cause for the reduction in atmospheric CO2 during the Last Glacial period. Despite the importance of the winds, it is currently not clear, from observations or model results, how they behave during the Last Glacial. Here, an atmospheric modelling study is performed to help determine likely changes in the SH westerly winds during the Last Glacial Maximum (LGM). Using LGM boundary conditions, the maximum in SH westerlies is strengthened by ∼+1 m s−1 and moved southward by ∼2° at the 850 hPa pressure level. Boundary layer stabilisation effects over equatorward extended LGM sea-ice can lead to a small apparent equatorward shift in the wind band at the surface. Further sensitivity analysis with individual boundary condition changes indicate that changes in sea surface temperatures are the strongest factor behind the wind change. The HadAM3 atmospheric simulations, along with published PMIP2 coupled climate model simulations, are then assessed against the newly synthesised database of moisture observations for the LGM. Although the moisture data is the most commonly cited evidence in support of a large equatorward shift in the SH winds during the LGM, none of the models that produce realistic LGM precipitation changes show such a large equatorward shift. In fact, the model which best simulates the moisture proxy data is the HadAM3 LGM simulation which shows a small poleward wind shift. While we cannot prove here that a large equatorward shift would not be able to reproduce the moisture data as well, we show that the moisture proxies do not provide an observational evidence base for it. Article in Journal/Newspaper Sea ice Southern Ocean University of Cambridge, Department of Earth Sciences: ESC Publications Southern Ocean Quaternary Science Reviews 64 104 120 |
institution |
Open Polar |
collection |
University of Cambridge, Department of Earth Sciences: ESC Publications |
op_collection_id |
ftucambridgeesc |
language |
English |
topic |
01 - Climate Change and Earth-Ocean Atmosphere Systems |
spellingShingle |
01 - Climate Change and Earth-Ocean Atmosphere Systems Sime, Louise C. Kohfeld, Karen E. Le Quéré, Corinne Wolff, Eric W. de Boer, Agatha M. Graham, Robert M. Bopp, Laurent Southern Hemisphere westerly wind changes during the Last Glacial Maximum: model-data comparison |
topic_facet |
01 - Climate Change and Earth-Ocean Atmosphere Systems |
description |
The Southern Hemisphere (SH) westerly winds are thought to be critical to global ocean circulation, productivity, and carbon storage. For example, an equatorward shift in the winds, though its affect on the Southern Ocean circulation, has been suggested as the leading cause for the reduction in atmospheric CO2 during the Last Glacial period. Despite the importance of the winds, it is currently not clear, from observations or model results, how they behave during the Last Glacial. Here, an atmospheric modelling study is performed to help determine likely changes in the SH westerly winds during the Last Glacial Maximum (LGM). Using LGM boundary conditions, the maximum in SH westerlies is strengthened by ∼+1 m s−1 and moved southward by ∼2° at the 850 hPa pressure level. Boundary layer stabilisation effects over equatorward extended LGM sea-ice can lead to a small apparent equatorward shift in the wind band at the surface. Further sensitivity analysis with individual boundary condition changes indicate that changes in sea surface temperatures are the strongest factor behind the wind change. The HadAM3 atmospheric simulations, along with published PMIP2 coupled climate model simulations, are then assessed against the newly synthesised database of moisture observations for the LGM. Although the moisture data is the most commonly cited evidence in support of a large equatorward shift in the SH winds during the LGM, none of the models that produce realistic LGM precipitation changes show such a large equatorward shift. In fact, the model which best simulates the moisture proxy data is the HadAM3 LGM simulation which shows a small poleward wind shift. While we cannot prove here that a large equatorward shift would not be able to reproduce the moisture data as well, we show that the moisture proxies do not provide an observational evidence base for it. |
format |
Article in Journal/Newspaper |
author |
Sime, Louise C. Kohfeld, Karen E. Le Quéré, Corinne Wolff, Eric W. de Boer, Agatha M. Graham, Robert M. Bopp, Laurent |
author_facet |
Sime, Louise C. Kohfeld, Karen E. Le Quéré, Corinne Wolff, Eric W. de Boer, Agatha M. Graham, Robert M. Bopp, Laurent |
author_sort |
Sime, Louise C. |
title |
Southern Hemisphere westerly wind changes during the Last Glacial Maximum: model-data comparison |
title_short |
Southern Hemisphere westerly wind changes during the Last Glacial Maximum: model-data comparison |
title_full |
Southern Hemisphere westerly wind changes during the Last Glacial Maximum: model-data comparison |
title_fullStr |
Southern Hemisphere westerly wind changes during the Last Glacial Maximum: model-data comparison |
title_full_unstemmed |
Southern Hemisphere westerly wind changes during the Last Glacial Maximum: model-data comparison |
title_sort |
southern hemisphere westerly wind changes during the last glacial maximum: model-data comparison |
publishDate |
2013 |
url |
http://eprints.esc.cam.ac.uk/2831/ http://eprints.esc.cam.ac.uk/2831/1/Kohfeld_et_al._-_2013_-_Southern_Hemisphere_westerly_wind_changes_during_t.pdf http://eprints.esc.cam.ac.uk/2831/2/1-s2.0-S0277379112005215-gr1.jpg http://www.sciencedirect.com/science/article/pii/S0277379112005215 https://doi.org/10.1016/j.quascirev.2012.12.008 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Sea ice Southern Ocean |
genre_facet |
Sea ice Southern Ocean |
op_relation |
http://eprints.esc.cam.ac.uk/2831/1/Kohfeld_et_al._-_2013_-_Southern_Hemisphere_westerly_wind_changes_during_t.pdf http://eprints.esc.cam.ac.uk/2831/2/1-s2.0-S0277379112005215-gr1.jpg Sime, Louise C. and Kohfeld, Karen E. and Le Quéré, Corinne and Wolff, Eric W. and de Boer, Agatha M. and Graham, Robert M. and Bopp, Laurent (2013) Southern Hemisphere westerly wind changes during the Last Glacial Maximum: model-data comparison. Quaternary Science Reviews, 64. pp. 104-120. ISSN 0277-3791 DOI https://doi.org/10.1016/j.quascirev.2012.12.008 <https://doi.org/10.1016/j.quascirev.2012.12.008> |
op_doi |
https://doi.org/10.1016/j.quascirev.2012.12.008 |
container_title |
Quaternary Science Reviews |
container_volume |
64 |
container_start_page |
104 |
op_container_end_page |
120 |
_version_ |
1766195617589100544 |