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| Uemura, Ryu; Motoyama, Hideaki; Masson-delmotte, Valerie; Jouzel, Jean; Kawamura, Kenji; Goto-azuma, Kumiko; Fujita, Shuji; Kuramoto, Takayuki; Hirabayashi, Motohiro; Miyake, Takayuki; Ohno, Hiroshi; Fujita, Koji; Abe-ouchi, Ayako; Iizuka, Yoshinori; Horikawa, Shinichiro; Igarashi, Makoto; Suzuki, Keisuke; Suzuki, Toshitaka; Fujii, Yoshiyuki. |
| The delta D temperature proxy in Antarctic ice cores varies in parallel with CO2 through glacial cycles. However, these variables display a puzzling asynchrony. Well-dated records of Southern Ocean temperature will provide crucial information because the Southern Ocean is likely key in regulating CO2 variations. Here, we perform multiple isotopic analyses on an Antarctic ice core and estimate temperature variations at this site and in the oceanic moisture source over the past 720,000 years, which extend the longest records by 300,000 years. Antarctic temperature is affected by large variations in local insolation that are induced by obliquity. At the obliquity periodicity, the Antarctic and ocean temperatures lag annual mean insolation. Further, the... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00496/60788/64966.pdf |
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| Wary, Melanie; Eynaud, Frederique; Swingedouw, Didier; Masson-delmotte, Valerie; Matthiessen, Jens; Kissel, Catherine; Zumaque, Jena; Rossignol, Linda; Jouzel, Jean. |
| Dansgaard-Oeschger oscillations constitute one of the most enigmatic features of the last glacial cycle. Their cold atmospheric phases have been commonly associated with cold sea-surface temperatures and expansion of sea ice in the North Atlantic and adjacent seas. Here, based on dinocyst analyses from the 48-30 ka interval of four sediment cores from the northern Northeast Atlantic and southern Norwegian Sea, we provide direct and quantitative evidence of a regional paradoxical seesaw pattern: cold Greenland and North Atlantic phases coincide with warmer sea-surface conditions and shorter seasonal sea-ice cover durations in the Norwegian Sea as compared to warm phases. Combined with additional palaeorecords and multi-model hosing simulations, our results... |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00420/53149/55328.pdf |
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