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| Waelbroeck, C.; Paul, A.; Kucera, M.; Rosell-mele, A.; Weinelt, M.; Schneider, R.; Mix, A. C.; Abelmann, A.; Armand, L.; Bard, E.; Barker, S.; Barrows, T. T.; Benway, H.; Cacho, I.; Chen, M. T.; Cortijo, E.; Crosta, X.; De Vernal, A.; Dokken, T.; Duprat, J.; Elderfield, H.; Eynaud, F.; Gersonde, R.; Hayes, A.; Henry, M.; Hillaire-marcel, C.; Huang, C. C.; Jansen, E.; Juggins, S.; Kallel, N.; Kiefer, T.; Kienast, M.; Labeyrie, L.; Leclaire, H.; Londeix, L.; Mangin, S.; Matthiessen, J.; Marret, F.; Meland, M.; Morey, A. E.; Mulitza, S.; Pflaumann, U.; Pisias, N. G.; Radi, T.; Rochon, A.; Rohling, E. J.; Sbaffi, L.; Schafer-neth, C.; Solignac, S.; Spero, H.; Tachikawa, K.; Turon, J. -l.. |
| Observation-based reconstructions of sea surface temperature from relatively stable periods in the past, such as the Last Glacial Maximum, represent an important means of constraining climate sensitivity and evaluating model simulations. The first quantitative global reconstruction of sea surface temperatures during the Last Glacial Maximum was developed by the Climate Long-Range Investigation, Mapping and Prediction (CLIMAP) project in the 1970s and 1980s. Since that time, several shortcomings of that earlier effort have become apparent. Here we present an updated synthesis of sea surface temperatures during the Last Glacial Maximum, rigorously defined as the period between 23 and 19 thousand years before present, from the Multiproxy Approach for the... |
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| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00218/32914/31395.pdf |
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| Peck, V. L.; Hall, I. R.; Zahn, R.; Elderfield, H.. |
| We present high-resolution records of upper ocean temperatures derived from Mg/Ca ratios of surface-dwelling Globigerina bulloides and subsurface-dwelling Neogloboquadrina pachyderma sinistral and the relative abundance of N. pachyderma sinistral for the period 55-8 ka BP from NE Atlantic sediment core MD01-2461. Millennial-scale temporal variability and longer-term trends in these records enable us to develop a detailed picture of past ocean conditions such as a weakening of thermocline intensity from marine isotope stage 3 (MIS 3) to the last glacial maximum (LGM). The correspondence of all temperature proxies and convergence of paired oxygen isotope (delta O-18) records from both planktonic species implies a breakdown in the thermocline and year-round... |
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| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00237/34797/33340.pdf |
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| Boessenkool, K. P.; Hall, I. R.; Elderfield, H.; Yashayaev, I.. |
| Variations in the near-bottom flow speed of Iceland-Scotland Overflow Water (ISOW) are documented in a 230-year-long deep-sea sediment record from the eastern flank of Reykjanes Ridge in the subpolar North Atlantic at (sub) decadal time scales. For recent decades, the ISOW palaeocurrent reconstructions show similarities with observational hydrographic data. Furthermore, recent ISOW flow changes fall mostly within the range of its variability of the past 230 years. The record also reveals a hitherto unrecognized coupling of deep flow speeds in the subpolar North Atlantic with the North Atlantic Oscillation (NAO) index, with more (less) vigorous ISOW flow during negative (positive) phases of the NAO. Our results suggest that the changes in ISOW vigor are... |
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Palavras-chave: Deep ocean circulation; North Atlantic Oscillation; Drift sediments. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00235/34646/33007.pdf |
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| Oliver, K. I. C.; Hoogakker, B. A. A.; Crowhurst, S.; Henderson, G. M.; Rickaby, R. E. M.; Edwards, N.r.; Elderfield, H.. |
| The isotopic composition of carbon, delta C-13, in seawater is used in reconstructions of ocean circulation, marine productivity, air-sea gas exchange, and biosphere carbon storage. Here, a synthesis of delta C-13 measurements taken from foraminifera in marine sediment cores over the last 150 000 years is presented. The dataset comprises previously published and unpublished data from benthic and planktonic records throughout the global ocean. Data are placed on a common delta O-18 age scale suitable for examining orbital timescale variability but not millennial events, which are removed by a 10 ka filter. Error estimates account for the resolution and scatter of the original data, and uncertainty in the relationship between delta C-13 of calcite and of... |
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| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00231/34258/32632.pdf |
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| Hall, I. R.; Boessenkool, K. P.; Barker, S.; Mccave, I. N.; Elderfield, H.. |
| The subpolar North Atlantic Ocean (SPNA) is of key importance for modulating the climate of NW Europe because of heat loss to the atmosphere from the North Atlantic Current. Although hydrographic properties of the surface SPNA vary on interannual to multidecadal timescales, hydrographic time series scarcely extend back beyond the 1950s. We present a 230 year long record of SPNA surface conditions reconstructed from a very high accumulation rate core that also registers changes in deep flow speed in the Iceland Basin. A lagged correlation is observed between the records of deep flow speed and stable oxygen isotopic composition of the surface SPNA (delta(18)O(w)), with strongest correlation when the paleoflow speed record leads by 15-20 years. This offset... |
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| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00231/34203/32762.pdf |
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