Precession modulation of the South Pacific westerly wind belt over the past million years
The southern westerly wind belt (SWW) interacts with the Antarctic Circumpolar Current and strongly impacts the Southern Ocean carbon budget, and Antarctic ice-sheet dynamics across glacial–interglacial cycles. We investigated precipitation-driven sediment input changes to the Southeast Pacific off...
Published in: | Proceedings of the National Academy of Sciences |
---|---|
Main Authors: | , , , , , , , , , |
Language: | unknown |
Published: |
2023
|
Subjects: | |
Online Access: | http://www.osti.gov/servlets/purl/1591825 https://www.osti.gov/biblio/1591825 https://doi.org/10.1073/pnas.1905847116 |
id |
ftosti:oai:osti.gov:1591825 |
---|---|
record_format |
openpolar |
spelling |
ftosti:oai:osti.gov:1591825 2023-07-30T03:57:10+02:00 Precession modulation of the South Pacific westerly wind belt over the past million years Lamy, Frank Chiang, John C. H. Martínez-Méndez, Gema Thierens, Mieke Arz, Helge W. Bosmans, Joyce Hebbeln, Dierk Lambert, Fabrice Lembke-Jene, Lester Stuut, Jan-Berend 2023-06-30 application/pdf http://www.osti.gov/servlets/purl/1591825 https://www.osti.gov/biblio/1591825 https://doi.org/10.1073/pnas.1905847116 unknown http://www.osti.gov/servlets/purl/1591825 https://www.osti.gov/biblio/1591825 https://doi.org/10.1073/pnas.1905847116 doi:10.1073/pnas.1905847116 54 ENVIRONMENTAL SCIENCES 2023 ftosti https://doi.org/10.1073/pnas.1905847116 2023-07-11T09:38:57Z The southern westerly wind belt (SWW) interacts with the Antarctic Circumpolar Current and strongly impacts the Southern Ocean carbon budget, and Antarctic ice-sheet dynamics across glacial–interglacial cycles. We investigated precipitation-driven sediment input changes to the Southeast Pacific off the southern margin of the Atacama Desert over the past one million years, revealing strong precession (19/23-ka) cycles. Our simulations with 2 ocean–atmosphere general circulation models suggest that observed cyclic rainfall changes are linked to meridional shifts in water vapor transport from the tropical Pacific toward the southern Atacama Desert. These changes reflect a precessional modulation of the split in the austral winter South Pacific jet stream. For precession maxima, we infer significantly enhanced rainfall in the southern Atacama Desert due to a stronger South Pacific split jet with enhanced subtropical/subpolar jets, and a weaker midlatitude jet. Conversely, we derive dry conditions in northern Chile related to reduced subtropical/subpolar jets and an enhanced midlatitude jet for precession minima. The presence of precessional cycles in the Pacific SWW, and lack thereof in other basins, indicate that orbital-scale changes of the SWW were not zonally homogeneous across the Southern Hemisphere, in contrast to the hemispherewide shifts of the SWW suggested for glacial terminations. Finally, the strengthening of the jet is unique to the South Pacific realm and might have affected winter-controlled changes in the mixed layer depth, the formation of intermediate water, and the buildup of sea-ice around Antarctica, with implications for the global overturning circulation and the oceanic storage of atmospheric CO 2 . Other/Unknown Material Antarc* Antarctic Antarctica Ice Sheet Sea ice Southern Ocean SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Antarctic Southern Ocean The Antarctic Austral Pacific Proceedings of the National Academy of Sciences 116 47 23455 23460 |
institution |
Open Polar |
collection |
SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
op_collection_id |
ftosti |
language |
unknown |
topic |
54 ENVIRONMENTAL SCIENCES |
spellingShingle |
54 ENVIRONMENTAL SCIENCES Lamy, Frank Chiang, John C. H. Martínez-Méndez, Gema Thierens, Mieke Arz, Helge W. Bosmans, Joyce Hebbeln, Dierk Lambert, Fabrice Lembke-Jene, Lester Stuut, Jan-Berend Precession modulation of the South Pacific westerly wind belt over the past million years |
topic_facet |
54 ENVIRONMENTAL SCIENCES |
description |
The southern westerly wind belt (SWW) interacts with the Antarctic Circumpolar Current and strongly impacts the Southern Ocean carbon budget, and Antarctic ice-sheet dynamics across glacial–interglacial cycles. We investigated precipitation-driven sediment input changes to the Southeast Pacific off the southern margin of the Atacama Desert over the past one million years, revealing strong precession (19/23-ka) cycles. Our simulations with 2 ocean–atmosphere general circulation models suggest that observed cyclic rainfall changes are linked to meridional shifts in water vapor transport from the tropical Pacific toward the southern Atacama Desert. These changes reflect a precessional modulation of the split in the austral winter South Pacific jet stream. For precession maxima, we infer significantly enhanced rainfall in the southern Atacama Desert due to a stronger South Pacific split jet with enhanced subtropical/subpolar jets, and a weaker midlatitude jet. Conversely, we derive dry conditions in northern Chile related to reduced subtropical/subpolar jets and an enhanced midlatitude jet for precession minima. The presence of precessional cycles in the Pacific SWW, and lack thereof in other basins, indicate that orbital-scale changes of the SWW were not zonally homogeneous across the Southern Hemisphere, in contrast to the hemispherewide shifts of the SWW suggested for glacial terminations. Finally, the strengthening of the jet is unique to the South Pacific realm and might have affected winter-controlled changes in the mixed layer depth, the formation of intermediate water, and the buildup of sea-ice around Antarctica, with implications for the global overturning circulation and the oceanic storage of atmospheric CO 2 . |
author |
Lamy, Frank Chiang, John C. H. Martínez-Méndez, Gema Thierens, Mieke Arz, Helge W. Bosmans, Joyce Hebbeln, Dierk Lambert, Fabrice Lembke-Jene, Lester Stuut, Jan-Berend |
author_facet |
Lamy, Frank Chiang, John C. H. Martínez-Méndez, Gema Thierens, Mieke Arz, Helge W. Bosmans, Joyce Hebbeln, Dierk Lambert, Fabrice Lembke-Jene, Lester Stuut, Jan-Berend |
author_sort |
Lamy, Frank |
title |
Precession modulation of the South Pacific westerly wind belt over the past million years |
title_short |
Precession modulation of the South Pacific westerly wind belt over the past million years |
title_full |
Precession modulation of the South Pacific westerly wind belt over the past million years |
title_fullStr |
Precession modulation of the South Pacific westerly wind belt over the past million years |
title_full_unstemmed |
Precession modulation of the South Pacific westerly wind belt over the past million years |
title_sort |
precession modulation of the south pacific westerly wind belt over the past million years |
publishDate |
2023 |
url |
http://www.osti.gov/servlets/purl/1591825 https://www.osti.gov/biblio/1591825 https://doi.org/10.1073/pnas.1905847116 |
geographic |
Antarctic Southern Ocean The Antarctic Austral Pacific |
geographic_facet |
Antarctic Southern Ocean The Antarctic Austral Pacific |
genre |
Antarc* Antarctic Antarctica Ice Sheet Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Sea ice Southern Ocean |
op_relation |
http://www.osti.gov/servlets/purl/1591825 https://www.osti.gov/biblio/1591825 https://doi.org/10.1073/pnas.1905847116 doi:10.1073/pnas.1905847116 |
op_doi |
https://doi.org/10.1073/pnas.1905847116 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
116 |
container_issue |
47 |
container_start_page |
23455 |
op_container_end_page |
23460 |
_version_ |
1772816169958375424 |