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Northern Hemisphere forcing of climatic cycles in Antarctica over the past 360,000 years |
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Northern Hemisphere forcing of climatic cycles in Antarctica over the past 360,000 years
Nature Vol. 448, Number 7156, pp. 912-917, 23 August 2007. doi:10.1038/nature06015. Kenji Kawamura1,2,9, Frédéric Parrenin3, Lorraine Lisiecki4, Ryu Uemura5, Françoise Vimeux6,7, Jeffrey P. Severinghaus2, Manuel A. Hutterli8, Takakiyo Nakazawa1, Shuji Aoki1, Jean Jouzel7, Maureen E. Raymo4, Koji Matsumoto1,9, Hisakazu Nakata1,9, Hideaki Motoyama5, Shuji Fujita5, Kumiko Goto-Azuma5, Yoshiyuki Fujii5, Okitsugu Watanabe5 |
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Center for Atmospheric and Oceanic Studies, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
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ABSTRACT: The Milankovitch theory of climate change proposes that glacial- interglacial cycles are driven by changes in summer insolation at high northern latitudes. The timing of climate change in the Southern Hemisphere at glacial-interglacial transitions (which are known as terminations) relative to variations in summer insolation in the Northern Hemisphere is an important test of this hypothesis. So far, it has only been possible to apply this test to the most recent termination, because the dating uncertainty associated with older terminations is too large to allow phase relationships to be determined. Here we present a new chronology of Antarctic climate change over the past 360,000 years that is based on the ratio of oxygen to nitrogen molecules in air trapped in the Dome Fuji and Vostok ice cores. This ratio is a proxy for local summer insolation, and thus allows the chronology to be constructed by orbital tuning without the need to assume a lag between a climate record and an orbital parameter. The accuracy of the chronology allows us to examine the phase relationships between climate records from the ice cores and changes in insolation. Our results indicate that orbital-scale Antarctic climate change lags Northern Hemisphere insolation by a few millennia, and that the increases in Antarctic temperature and atmospheric carbon dioxide concentration during the last four terminations occurred within the rising phase of Northern Hemisphere summer insolation. These results support the Milankovitch theory that Northern Hemisphere summer insolation triggered the last four deglaciations. |
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Download data from the WDC Paleo archive: Dry Extraction CO2 Data for 1-264 KYr BY2K (Text) Wet Extraction CO2 Data for 1-340 KYr BY2K (Text) δ18O Data for 1-340 KYr BY2K (Text) O2/N2 timescale (DFO-2006), 0-2504 m (0-340 kyr) (Text) Preliminary Temperature Reconstruction, 0-340 kyr (Text) CO2, δ18O, Timescale, and Temperature Data for 1-340 KYr BY2K (Excel) |
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To read or view the full study, please visit the Nature website. It was published in Nature, Vol. 448, Number 7156, pp. 912-917, 23 August 2007. |
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http://www.ncdc.noaa.gov/paleo/pubs/kawamura2007/kawamura2007.html Downloaded Thursday, 01-Aug-2013 19:37:38 EDT Last Updated Wednesday, 20-Aug-2008 11:24:29 EDT by paleo@noaa.gov Please see the Paleoclimatology Contact Page or the NCDC Contact Page if you have questions or comments. |