Astronomically-induced Mid-Brunhes Transition in the Southern and Deep Oceans
The interglacials after 430 ka (ka: 1000 years) ago were characterized by warmer climates and higher atmospheric CO2 concentrations than the interglacials before, but the cause of this climatic transition (the so-called Mid- Brunhes Event, MBE) is unknown. Based on model simulations, my results show...
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ftunistlouisbrus:oai:dial.uclouvain.be:boreal:212382 2024-05-12T07:54:04+00:00 Astronomically-induced Mid-Brunhes Transition in the Southern and Deep Oceans Yin, Qiuzhen EGU General Assembly UCL - SST/ELI/ELIC - Earth & Climate 2013 http://hdl.handle.net/2078.1/212382 eng eng boreal:212382 http://hdl.handle.net/2078.1/212382 info:eu-repo/semantics/conferenceObject 2013 ftunistlouisbrus 2024-04-18T17:28:19Z The interglacials after 430 ka (ka: 1000 years) ago were characterized by warmer climates and higher atmospheric CO2 concentrations than the interglacials before, but the cause of this climatic transition (the so-called Mid- Brunhes Event, MBE) is unknown. Based on model simulations, my results show that, in response to insolation changes only, feedbacks between sea ice, temperature, evaporation and salinity caused vigorous pre-MBE Antarctic Bottom Water formation and Southern Ocean ventilation. My results also show that strong Westerlies increased the pre-MBE overturning in the Southern Ocean via an increased latitudinal insolation gradient created by changes in eccentricity during austral winter and in obliquity during austral summer. The stronger bottom water formation led to a cooler deep ocean during the older interglacials. These insolation-induced differences in the deep-sea temperature and in the Southern Ocean ventilation between the more recent interglacials and the older ones were not expected, because there is no straightforward visible systematic difference in the astronomical parameters between the interglacials before and after 430 ka ago. Rather than being a real “eventâ€, the apparent MBE (i.e. the difference in the interglacial intensity before and after 430 ka BP) appears in my results to come from the complex response of the climate system to the astronomical and insolation forcings prevailing before and after 430 ka BP. This does not mean that nothing could have happened between MIS-13 and MIS-11 which might have amplified such difference. Given the important roles of the Southern and Deep Oceans on the carbon cycle, these findings are a first step towards understanding the magnitude change of the interglacial CO2 concentration around 430 ka. Conference Object Antarc* Antarctic Sea ice Southern Ocean DIAL@USL-B (Université Saint-Louis, Bruxelles) Antarctic Austral Southern Ocean |
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Open Polar |
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DIAL@USL-B (Université Saint-Louis, Bruxelles) |
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ftunistlouisbrus |
language |
English |
description |
The interglacials after 430 ka (ka: 1000 years) ago were characterized by warmer climates and higher atmospheric CO2 concentrations than the interglacials before, but the cause of this climatic transition (the so-called Mid- Brunhes Event, MBE) is unknown. Based on model simulations, my results show that, in response to insolation changes only, feedbacks between sea ice, temperature, evaporation and salinity caused vigorous pre-MBE Antarctic Bottom Water formation and Southern Ocean ventilation. My results also show that strong Westerlies increased the pre-MBE overturning in the Southern Ocean via an increased latitudinal insolation gradient created by changes in eccentricity during austral winter and in obliquity during austral summer. The stronger bottom water formation led to a cooler deep ocean during the older interglacials. These insolation-induced differences in the deep-sea temperature and in the Southern Ocean ventilation between the more recent interglacials and the older ones were not expected, because there is no straightforward visible systematic difference in the astronomical parameters between the interglacials before and after 430 ka ago. Rather than being a real “eventâ€, the apparent MBE (i.e. the difference in the interglacial intensity before and after 430 ka BP) appears in my results to come from the complex response of the climate system to the astronomical and insolation forcings prevailing before and after 430 ka BP. This does not mean that nothing could have happened between MIS-13 and MIS-11 which might have amplified such difference. Given the important roles of the Southern and Deep Oceans on the carbon cycle, these findings are a first step towards understanding the magnitude change of the interglacial CO2 concentration around 430 ka. |
author2 |
UCL - SST/ELI/ELIC - Earth & Climate |
format |
Conference Object |
author |
Yin, Qiuzhen EGU General Assembly |
spellingShingle |
Yin, Qiuzhen EGU General Assembly Astronomically-induced Mid-Brunhes Transition in the Southern and Deep Oceans |
author_facet |
Yin, Qiuzhen EGU General Assembly |
author_sort |
Yin, Qiuzhen |
title |
Astronomically-induced Mid-Brunhes Transition in the Southern and Deep Oceans |
title_short |
Astronomically-induced Mid-Brunhes Transition in the Southern and Deep Oceans |
title_full |
Astronomically-induced Mid-Brunhes Transition in the Southern and Deep Oceans |
title_fullStr |
Astronomically-induced Mid-Brunhes Transition in the Southern and Deep Oceans |
title_full_unstemmed |
Astronomically-induced Mid-Brunhes Transition in the Southern and Deep Oceans |
title_sort |
astronomically-induced mid-brunhes transition in the southern and deep oceans |
publishDate |
2013 |
url |
http://hdl.handle.net/2078.1/212382 |
geographic |
Antarctic Austral Southern Ocean |
geographic_facet |
Antarctic Austral Southern Ocean |
genre |
Antarc* Antarctic Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Sea ice Southern Ocean |
op_relation |
boreal:212382 http://hdl.handle.net/2078.1/212382 |
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1798846543054241792 |