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| Govin, Aline; Varma, Vidya; Prange, Matthias. |
| This study documents the long-term evolution of western African precipitation during the Last Interglacial (LIG). We compare geochemical records obtained on nine sediment cores from the western African margin to a transient simulation (130–115 ka) performed with an ocean-atmosphere general circulation model and insolation as sole forcing. Good agreement between proxy records and model outputs indicates that long-term changes in western African precipitation largely responded to insolation variations during most of the LIG. After an early LIG dry phase (related to high-latitude iceberg melting or dating uncertainties), boreal summer insolation controlled the intensification of the North African monsoon between 127 and 122 ka, perhaps facilitating human... |
| Tipo: Text |
Palavras-chave: Last Interglacial; Africa; Precipitation; Astronomical forcing; Marine sediment cores; Model simulations. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40164/38778.pdf |
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| Zhang, Xiao; Prange, Matthias; Merkel, Ute; Schulz, Michael. |
| Pronounced millennial-scale climate variability during marine isotope stage 3 (MIS3) is considered to be linked to changes in the state of the Atlantic meridional overturning circulation (AMOC), i.e., a warm interstadial/cold stadial state corresponds to a strong/weak AMOC. Based on a series of freshwater hosing/extraction experiments with the state-of-the-art Community Climate System Model version 3, we construct a global spatial fingerprint of oceanic temperature anomalies in response to AMOC changes under MIS3 boundary conditions. Highest sensitivity to AMOC changes, especially in summer, is found in northeastern North Atlantic sea surface temperature, but a characteristic temperature fingerprint is also found at subsurface levels. After testing... |
| Tipo: Text |
Palavras-chave: Atlantic meridional overturning circulation; Dansgaard-Oeschger events; Global climate modeling. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00351/46267/46052.pdf |
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| Ronge, Thomas A.; Steph, Silke; Tiedemann, Ralf; Prange, Matthias; Merkel, Ute; Nuernberg, Dirk; Kuhn, Gerhard. |
| Glacial/interglacial changes in Southern Ocean's air-sea gas exchange have been considered as important mechanisms contributing to the glacial/interglacial variability in atmospheric CO2. Hence, understanding past variability in Southern Ocean intermediate to deep water chemistry and circulation is fundamental to constrain the role of these processes on modulating glacial/interglacial changes in the global carbon cycle. Our study focused on the glacial/interglacial variability in the vertical extent of southwest Pacific Antarctic Intermediate Water (AAIW). We compared carbon and oxygen isotope records from epibenthic foraminifera of sediment cores bathed in modern AAIW and Upper Circumpolar Deep Water (UCDW; 943–2066 m water depth) to monitor changes in... |
| Tipo: Text |
Palavras-chave: AAIW; UCDW; SW-Pacific; Stable isotopes. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00294/40568/39465.pdf |
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| Kleinen, Thomas; Hildebrandt, Steffi; Prange, Matthias; Rachmayani, Rima; Mueller, Stefanie; Bezrukova, Elena; Brovkin, Victor; Tarasov, Pavel E.. |
| The climate of Marine Isotope Stage (MIS) 11, the interglacial roughly 400,000 years ago, is investigated for four time slices, 416, 410, 400, and 396 ka. We compare results from two climate models, the earth system model of intermediate complexity CLIMBER2-LPJ and the general circulation model CCSM3, to reconstructions of MIS 11 temperature, precipitation and vegetation, mainly from terrestrial records. The overall picture is that MIS 11 was a relatively warm interglacial in comparison to preindustrial, with Northern Hemisphere (NH) summer temperatures early in MIS 11 (416-410 ka) warmer than preindustrial, though winters were cooler. Later in MIS 11, especially around 400 ka, conditions were cooler in the NH summer, mainly in the high latitudes. Climate... |
| Tipo: Text |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00289/40071/39333.pdf |
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