Modulation of the bipolar seesaw in the Southeast Pacific during Termination 1
The termination of the last ice age (Termination 1; T1) is crucial for our understanding of global climate change and for the validation of climate models. There are still a number of open questions regarding for example the exact timing and the mechanisms involved in the initiation of deglaciation...
Published in: | Earth and Planetary Science Letters |
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_235921 2024-06-02T07:57:09+00:00 Modulation of the bipolar seesaw in the Southeast Pacific during Termination 1 Lamy, F. Kaiser, J. Arz, H. Hebbeln, D. Ninnemann, U. Timm, O. Timmermann, A. Toggweiler, J. 5.2 Climate Dynamics and Landscape Evolution, 5.0 Earth Surface Processes, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum 2007 https://gfzpublic.gfz-potsdam.de/pubman/item/item_235921 unknown info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2007.04.040 https://gfzpublic.gfz-potsdam.de/pubman/item/item_235921 Earth and Planetary Science Letters 550 - Earth sciences info:eu-repo/semantics/article 2007 ftgfzpotsdam https://doi.org/10.1016/j.epsl.2007.04.040 2024-05-07T04:20:38Z The termination of the last ice age (Termination 1; T1) is crucial for our understanding of global climate change and for the validation of climate models. There are still a number of open questions regarding for example the exact timing and the mechanisms involved in the initiation of deglaciation and the subsequent interhemispheric pattern of the warming. Our study is based on a well-dated and high-resolution alkenone-based sea surface temperature (SST) record from the SE-Pacific off southern Chile (Ocean Drilling Project Site 1233) showing that deglacial warming at the northern margin of the Antarctic Circumpolar Current system (ACC) began shortly after 19,000 years BP (19 kyr BP). The timing is largely consistent with Antarctic ice-core records but the initial warming in the SE-Pacific is more abrupt suggesting a direct and immediate response to the slowdown of the Atlantic thermohaline circulation through the bipolar seesaw mechanism. This response requires a rapid transfer of the Atlantic signal to the SE-Pacific without involving the thermal inertia of the Southern Ocean that may contribute to the substantially more gradual deglacial temperature rise seen in Antarctic ice-cores. A very plausible mechanism for this rapid transfer is a seesaw-induced change of the coupled ocean–atmosphere system of the ACC and the southern westerly wind belt. In addition, modelling results suggest that insolation changes and the deglacial CO2 rise induced a substantial SST increase at our site location but with a gradual warming structure. The similarity of the two-step rise in our proxy SSTs and CO2 over T1 strongly demands for a forcing mechanism influencing both, temperature and CO2. As SSTs at our coring site are particularly sensitive to latitudinal shifts of the ACC/southern westerly wind belt system, we conclude that such latitudinal shifts may substantially affect the upwelling of deepwater masses in the Southern Ocean and thus the release of CO2 to the atmosphere as suggested by the conceptual model of [Toggweiler, ... Article in Journal/Newspaper Antarc* Antarctic ice core Southern Ocean GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Antarctic Pacific Southern Ocean The Antarctic Earth and Planetary Science Letters 259 3-4 400 413 |
institution |
Open Polar |
collection |
GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
unknown |
topic |
550 - Earth sciences |
spellingShingle |
550 - Earth sciences Lamy, F. Kaiser, J. Arz, H. Hebbeln, D. Ninnemann, U. Timm, O. Timmermann, A. Toggweiler, J. Modulation of the bipolar seesaw in the Southeast Pacific during Termination 1 |
topic_facet |
550 - Earth sciences |
description |
The termination of the last ice age (Termination 1; T1) is crucial for our understanding of global climate change and for the validation of climate models. There are still a number of open questions regarding for example the exact timing and the mechanisms involved in the initiation of deglaciation and the subsequent interhemispheric pattern of the warming. Our study is based on a well-dated and high-resolution alkenone-based sea surface temperature (SST) record from the SE-Pacific off southern Chile (Ocean Drilling Project Site 1233) showing that deglacial warming at the northern margin of the Antarctic Circumpolar Current system (ACC) began shortly after 19,000 years BP (19 kyr BP). The timing is largely consistent with Antarctic ice-core records but the initial warming in the SE-Pacific is more abrupt suggesting a direct and immediate response to the slowdown of the Atlantic thermohaline circulation through the bipolar seesaw mechanism. This response requires a rapid transfer of the Atlantic signal to the SE-Pacific without involving the thermal inertia of the Southern Ocean that may contribute to the substantially more gradual deglacial temperature rise seen in Antarctic ice-cores. A very plausible mechanism for this rapid transfer is a seesaw-induced change of the coupled ocean–atmosphere system of the ACC and the southern westerly wind belt. In addition, modelling results suggest that insolation changes and the deglacial CO2 rise induced a substantial SST increase at our site location but with a gradual warming structure. The similarity of the two-step rise in our proxy SSTs and CO2 over T1 strongly demands for a forcing mechanism influencing both, temperature and CO2. As SSTs at our coring site are particularly sensitive to latitudinal shifts of the ACC/southern westerly wind belt system, we conclude that such latitudinal shifts may substantially affect the upwelling of deepwater masses in the Southern Ocean and thus the release of CO2 to the atmosphere as suggested by the conceptual model of [Toggweiler, ... |
author2 |
5.2 Climate Dynamics and Landscape Evolution, 5.0 Earth Surface Processes, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum |
format |
Article in Journal/Newspaper |
author |
Lamy, F. Kaiser, J. Arz, H. Hebbeln, D. Ninnemann, U. Timm, O. Timmermann, A. Toggweiler, J. |
author_facet |
Lamy, F. Kaiser, J. Arz, H. Hebbeln, D. Ninnemann, U. Timm, O. Timmermann, A. Toggweiler, J. |
author_sort |
Lamy, F. |
title |
Modulation of the bipolar seesaw in the Southeast Pacific during Termination 1 |
title_short |
Modulation of the bipolar seesaw in the Southeast Pacific during Termination 1 |
title_full |
Modulation of the bipolar seesaw in the Southeast Pacific during Termination 1 |
title_fullStr |
Modulation of the bipolar seesaw in the Southeast Pacific during Termination 1 |
title_full_unstemmed |
Modulation of the bipolar seesaw in the Southeast Pacific during Termination 1 |
title_sort |
modulation of the bipolar seesaw in the southeast pacific during termination 1 |
publishDate |
2007 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_235921 |
geographic |
Antarctic Pacific Southern Ocean The Antarctic |
geographic_facet |
Antarctic Pacific Southern Ocean The Antarctic |
genre |
Antarc* Antarctic ice core Southern Ocean |
genre_facet |
Antarc* Antarctic ice core Southern Ocean |
op_source |
Earth and Planetary Science Letters |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2007.04.040 https://gfzpublic.gfz-potsdam.de/pubman/item/item_235921 |
op_doi |
https://doi.org/10.1016/j.epsl.2007.04.040 |
container_title |
Earth and Planetary Science Letters |
container_volume |
259 |
container_issue |
3-4 |
container_start_page |
400 |
op_container_end_page |
413 |
_version_ |
1800739279999074304 |