Migration of the Antarctic Polar Front over the last glacial cycle
| Type | Article | ||||||||
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| Date | 2022-03-08 | ||||||||
| Language | English | ||||||||
| Author(s) | Thöle Lena1, 2, 3, Ai Xuyuan 2, 4, Auderset Alexandra2, Schmitt Mareike2, Moretti Simone2, Studer Anja2, 5, Michel Elisabeth6, Wegmann Martin7, Mazaud Alain6, Bijl Peter3, Sigman Daniel4, Martinez-Garcia Alfredo2, Jaccard Samuel L.1, 8 |
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| Affiliation(s) | 1 : Institute of Geological Sciences and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland 2 : Max Planck Institute for Chemistry, Climate Geochemistry Department, Mainz, Germany 3 : Marine Palynology and Paleoceanography, Department of Earth Sciences, Utrecht University, The Netherlands 4 : Department of Geosciences, Princeton University, Princeton, NJ, USA 5 : Aquatic and Isotope Biogeochemistry, Department of Environmental Sciences, University of Basel, Switzerland 6 : Laboratoire de Sciences et de l’Environnement (LSCE), Gif-sur-Yvette, France 7 : Institute of Geography and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland. 8 : Institute of Earth Sciences, University of Lausanne, Lausanne, Switzerland |
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| Source | Research Square. (Research Square Platform LLC), 2022-03-08 , N. Version 1 | ||||||||
| DOI | 10.21203/rs.3.rs-1364006/v1 | ||||||||
| Note | This is a preprint ; it has not been peer reviewed by a journal | ||||||||
| Keyword(s) | Paleoceanography, glacial–interglacial changes, Southern Ocean, ACC, atmospheric CO2 | ||||||||
| Abstract | The Southern Hemisphere Westerly Winds (SWW) drive upwelling south of the Antarctic Polar Front (PF) that vents CO2 to the atmosphere. During the ice ages, a northward (equatorward) shift of the PF may have reduced this CO2 venting, helping to explain the lower atmospheric CO2 concentration of those times. However, evidence of PF migration is lacking. Here, we report biomarker–based sea surface temperature (SST) reconstructions from two marine sediment cores at different latitudes in the Southern Indian Ocean across the last glacial cycle. Using a quantitative framework for the effect of the PF on meridional SST gradient, we show that the PF underwent an equatorward shift during the ice ages. The PF latitude reconstruction, when compared with other data, also suggests a role for Earth’s axial tilt in the strength and latitude range of SWW-driven upwelling, which may explain previously noted deviations in atmospheric CO2 from a simple correlation with Antarctic climate. |
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