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| Dannenmann, S; Linsley, Bk; Oppo, Dw; Rosenthal, Y; Beaufort, L. |
| We have generated a new high-resolution record of variations in planktonic foraminiferal oxygen isotopes (delta(18)O) and Mg/Ca from a sediment core (IMAGES 97-2141) in the Sulu Sea located in the Philippine archipelago of western tropical Pacific. This record reveals distinct, suborbital-scale delta(18)O changes, most notably during Marine Isotope Stage 3 (MIS3) (similar to30,000 to 60,000 years B.P.). The amplitudes of these delta(18)O fluctuations (0.4 to 0.7parts per thousand) exceed that which can be attributed to sea level changes and must be due to changes in sea surface conditions. In the same interval, variations in planktonic foraminifera Mg/Ca suggest that suborbital surface ocean temperature variations of 1 to 1.5degreesC in the Sulu Sea were... |
| Tipo: Text |
Palavras-chave: Paleoceanography; Isotope stage 3; SE Asian Monsoon; Mg/Ca; Oxygen isotopes; Millennial-scale climate change; Paleoceanography; Climate dynamics. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00226/33681/32046.pdf |
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| Yiou, P; Vimeux, F; Jouzel, J. |
| The four climatic cycles obtained from the Vostok ice core offer a unique opportunity to study the high-frequency paleoclimatic variability, i.e., on time scales smaller than 15 kyr. We focused our study on the deuterium (deltaD) and deuterium excess (d) records, which are proxies for local temperature and remote evaporation source temperature and hence give us access to spatial climatic variations. Spectral analyses of paleoclimatic records have shown that the last glacial period (110-15 kyr before present) is characterized by large and fast temperature oscillations. Examples of such variations in the Northern Hemisphere are the so-called Dansgaard-Oeschger oscillations and Heinrich events. At Vostok, these oscillations are also imprinted in the ice, with... |
| Tipo: Text |
Palavras-chave: Climate dynamics; Antarctica; Meteorology and Atmospheric Dynamics; Paleoclimatology; Paleoceanography. |
| Ano: 2001 |
URL: https://archimer.ifremer.fr/doc/00221/33219/31699.pdf |
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| Couldrey, Matthew P.; Oliver, Kevin I. C.; Yool, Andrew; Halloran, Paul R.; Achterberg, Eric P.. |
| The North Atlantic is an important basin for the global ocean's uptake of anthropogenic and natural carbon dioxide (CO2), but the mechanisms controlling this carbon flux are not fully understood. The air-sea flux of CO2, F, is the product of a gas transfer velocity, k, the air-sea CO2 concentration gradient, Delta pCO(2), and the temperature-and salinity-dependent solubility coefficient, alpha, k is difficult to constrain, representing the dominant uncertainty in F on short (instantaneous to interannual) timescales. Previous work shows that in the North Atlantic, Delta pCO(2) and k both contribute significantly to interannual F variability but that k is unimportant for multidecadal variability. On some timescale between interannual and multidecadal, gas... |
| Tipo: Text |
Palavras-chave: Carbon flux; Gas transfer velocity; Carbon cycle; Ocean model; Climate dynamics; Variability. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00383/49418/49868.pdf |
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| Oppo, Dw; Linsley, Bk; Rosenthal, Y; Dannenmann, S; Beaufort, L. |
| A detailed record of planktic delta(18)O from a sediment core in the Sulu Sea, located between the South China Sea and the western Pacific warm pool, reveals that for the past 400 kyr (1 kyr = 1000 years), delta(18)O variability on orbital timescales is similar to that caused by changes in ice volume alone. This result indicates that in the Sulu Sea, temperature-driven changes in planktic delta(18)O on orbital times scales were generally compensated for by the effects of sea level and changes in seasonal monsoon intensity on the local freshwater budget, as well as by other changes in the tropical hydrologic cycle and their attendant effects on surface water delta(18)O. Increased freshening of the western tropical Pacific warm pool is reminiscent of La Nina... |
| Tipo: Text |
Palavras-chave: Sulu Sea; Tropical hydrography; East Asian monsoon; IMAGES; Suborbital climate variability; Sea level; Paleoceanography; Marginal and semienclosed seas; Climate dynamics. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00226/33680/32047.pdf |
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| Govin, A.; Capron, E.; Tzedakis, P. C.; Verheyden, S.; Ghaleb, B.; Hillaire-marcel, C.; St-onge, G.; Stoner, J. S.; Bassinot, F.; Bazin, L.; Blunier, T.; Combourieu-nebout, N.; El Ouahabi, A.; Genty, D.; Gersonde, R.; Jimenez-amat, P.; Landais, A.; Martrat, B.; Masson-delmotte, V.; Parrenin, F.; Seidenkrantz, M. -s.; Veres, D.; Waelbroeck, C.; Zahn, R.. |
| The Last Interglacial (LIG) represents an invaluable case study to investigate the response of components of the Earth system to global warming. However, the scarcity of absolute age constraints in most archives leads to extensive use of various stratigraphic alignments to different reference chronologies. This feature sets limitations to the accuracy of the stratigraphic assignment of the climatic sequence of events across the globe during the LIG. Here, we review the strengths and limitations of the methods that are commonly used to date or develop chronologies in various climatic archives for the time span (similar to 140 -100 ka) encompassing the penultimate deglaciation, the LIG and the glacial inception. Climatic hypotheses underlying record... |
| Tipo: Text |
Palavras-chave: Last Interglacial; Penultimate deglaciation; Last glacial inception; Chronology; Corals; Speleothems; Ice cores; Marine sediments; Peat and lake sediments; Climate dynamics. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00496/60802/64786.pdf |
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| Grousset, Fe; Cortijo, E; Huon, S; Herve, L; Richter, T; Burdloff, D; Duprat, J; Weber, O. |
| Theories explaining the origin of the abrupt, massive discharges of ice-rafted detritus (IRD) into the glacial North Atlantic (the Heinrich layers (HLs)) generally point to the Laurentide ice sheet as the sole source of these events, until it was found that the IRDs also originated from Icelandic and European ice sheets [Bond and Lotti, 1995; Snoeckx er al., 1999; Grousset et al., 2000]. This apparent contradiction must be reconciled as it raises fundamental questions about the mechanism(s) of HL origin. We have analyzed two similar to 12 cm thick HLs in an ultrahigh-resolution mode (1-2 century intervals) in a mid-Atlantic ridge piston core. The delta O-18 record (N. pachyderma left coiling) reveals strong excursions induced by the melting of the... |
| Tipo: Text |
Palavras-chave: Climate and interannual variability; Climate dynamics; Radiogenic isotope geochemistry. |
| Ano: 2001 |
URL: https://archimer.ifremer.fr/doc/00221/33190/31786.pdf |
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