Effect of ocean gateway changes under greenhouse warmth

The role of tectonic Southern Ocean gateway changes in driving Antarctic climate change at the Eocene– Oligocene boundary remains a topic of debate. One approach taken in previous idealized modeling studies of gateway effects has been to alter modern boundary conditions, whereby the Drake Passage be...

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Main Authors: Willem P. Sijp, Matthew H. England, J. R. Toggweiler
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Published: 2009
Subjects:
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.677.6699
http://web.science.unsw.edu.au/%7Ematthew/SIJP_JCLI_DP4_2008.pdf
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spelling ftciteseerx:oai:CiteSeerX.psu:10.1.1.677.6699 2023-05-15T13:39:52+02:00 Effect of ocean gateway changes under greenhouse warmth Willem P. Sijp Matthew H. England J. R. Toggweiler The Pennsylvania State University CiteSeerX Archives 2009 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.677.6699 http://web.science.unsw.edu.au/%7Ematthew/SIJP_JCLI_DP4_2008.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.677.6699 http://web.science.unsw.edu.au/%7Ematthew/SIJP_JCLI_DP4_2008.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://web.science.unsw.edu.au/%7Ematthew/SIJP_JCLI_DP4_2008.pdf text 2009 ftciteseerx 2016-01-08T17:41:38Z The role of tectonic Southern Ocean gateway changes in driving Antarctic climate change at the Eocene– Oligocene boundary remains a topic of debate. One approach taken in previous idealized modeling studies of gateway effects has been to alter modern boundary conditions, whereby the Drake Passage becomes closed. Here, the authors follow this approach but vary atmospheric pCO2 over a range of values when comparing gateway configurations. They find a significantly greater sensitivity of Antarctic temperatures to Southern Ocean gateway changes when atmospheric pCO2 is high than when concentrations are low and the ambient climate is cool. In particular, the closure of the Drake Passage (DP) gap is a necessary condition for the existence of ice-free Antarctic conditions at high CO2 concentrations in this coupled climate model. The absence of the Antarctic Circumpolar Current (ACC) is particularly conducive to warmAntarctic conditions at higher CO2 concentrations, which is markedly different from previous simulations conducted under present-day CO2 conditions. The reason for this is the reduction of sea ice associated with higher CO2. Antarctic sea surface temperature and surface air temperature warming due to a closed DP gap reach values around;58 and;78C, respectively, for high concentrations of CO2 (above 1250 ppm). In other words, the authors find a significantly greater sensitivity of Antarctic temperatures to atmospheric CO2 concentration when the DP is closed compared to when it is open. The presence of a DP gap inhibits a return to warmer and more Eocene-like Antarctic and deep ocean conditions, even under enhanced atmospheric greenhouse gas concentrations. 1. Text Antarc* Antarctic Drake Passage Sea ice Southern Ocean Unknown Antarctic Drake Passage Southern Ocean The Antarctic
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description The role of tectonic Southern Ocean gateway changes in driving Antarctic climate change at the Eocene– Oligocene boundary remains a topic of debate. One approach taken in previous idealized modeling studies of gateway effects has been to alter modern boundary conditions, whereby the Drake Passage becomes closed. Here, the authors follow this approach but vary atmospheric pCO2 over a range of values when comparing gateway configurations. They find a significantly greater sensitivity of Antarctic temperatures to Southern Ocean gateway changes when atmospheric pCO2 is high than when concentrations are low and the ambient climate is cool. In particular, the closure of the Drake Passage (DP) gap is a necessary condition for the existence of ice-free Antarctic conditions at high CO2 concentrations in this coupled climate model. The absence of the Antarctic Circumpolar Current (ACC) is particularly conducive to warmAntarctic conditions at higher CO2 concentrations, which is markedly different from previous simulations conducted under present-day CO2 conditions. The reason for this is the reduction of sea ice associated with higher CO2. Antarctic sea surface temperature and surface air temperature warming due to a closed DP gap reach values around;58 and;78C, respectively, for high concentrations of CO2 (above 1250 ppm). In other words, the authors find a significantly greater sensitivity of Antarctic temperatures to atmospheric CO2 concentration when the DP is closed compared to when it is open. The presence of a DP gap inhibits a return to warmer and more Eocene-like Antarctic and deep ocean conditions, even under enhanced atmospheric greenhouse gas concentrations. 1.
author2 The Pennsylvania State University CiteSeerX Archives
format Text
author Willem P. Sijp
Matthew H. England
J. R. Toggweiler
spellingShingle Willem P. Sijp
Matthew H. England
J. R. Toggweiler
Effect of ocean gateway changes under greenhouse warmth
author_facet Willem P. Sijp
Matthew H. England
J. R. Toggweiler
author_sort Willem P. Sijp
title Effect of ocean gateway changes under greenhouse warmth
title_short Effect of ocean gateway changes under greenhouse warmth
title_full Effect of ocean gateway changes under greenhouse warmth
title_fullStr Effect of ocean gateway changes under greenhouse warmth
title_full_unstemmed Effect of ocean gateway changes under greenhouse warmth
title_sort effect of ocean gateway changes under greenhouse warmth
publishDate 2009
url http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.677.6699
http://web.science.unsw.edu.au/%7Ematthew/SIJP_JCLI_DP4_2008.pdf
geographic Antarctic
Drake Passage
Southern Ocean
The Antarctic
geographic_facet Antarctic
Drake Passage
Southern Ocean
The Antarctic
genre Antarc*
Antarctic
Drake Passage
Sea ice
Southern Ocean
genre_facet Antarc*
Antarctic
Drake Passage
Sea ice
Southern Ocean
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http://web.science.unsw.edu.au/%7Ematthew/SIJP_JCLI_DP4_2008.pdf
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