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| Titel |
Comparaison of last centuries variability in the eastern and central Pacific reconstructed from massive coral geochemical tracers |
| VerfasserIn |
Melanie Moreau, Thierry Corrège, Julie Cole, Florence Le Cornec, Lawrence Edwards, Hai Cheng, Karine Charlier |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250086881
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| Publikation (Nr.) |
 EGU/EGU2014-823.pdf |
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| Zusammenfassung |
| The tropical Pacific is under the influence of different climate modes (from the seasonal to the
decadal scale) and, through teleconnections, affects the global climate. At the seasonal scale
the latitudinal migration of the Intertropical Convergence Zone (ITCZ) drive the hydrological
dynamic of the tropical zone. The tropical Pacific is also a place of strong and variable zonal
gradients due to the El Niño Southern Oscillation phenomenon (ENSO) at the interannual
scale. A good amount of data is available in the western and the central part of the
Pacific to reconstruct climatic parameters such as sea surface temperature (SST)
and sea surface salinity (SSS) while there is a striking lack of data in the eastern
part. To better estimate the zonal gradients in the tropical Pacific and the different
climatic processes in the last two centuries, we present geochemical results (Sr/Ca and
δ18O) obtained from aragonitic coral skeletons (Porites genus) from Clipperton
atoll (10°N, 109°W) and the Marquesas Islands (10°S, 140°W). Clipperton
being the only atoll located in the northern part of the ITCZ latitudinal migration
area, information about eastern Pacific hydrological cycle and advection can be
obtained. On the other hand, the precise chronology of the Clipperton coral and the
comparaison with the records from the Marquesas Islands allows us to calculate
SST gradients between the eastern and central Pacific. We will discuss about the
recent theory of an El Niño-like condition triggered by a slowdown of the equatorial
Walker circulation under global warming. We will also discuss about the evolution
(frequency and intensity) of the two differents “flavours” of El Niño (e.g. the canonical
eastern El Niño and the central El Niño Modoki) through the 20thcentury. Indeed
the canonical El Niño is characterised by a maximum SST anomaly in the eastern
Pacific while the El Niño Modoki is characterised by a maximum SST anomaly
persisting in the central Pacific. A better comprehension of the evolution of the both
kind of El Niño is a major issue because each of them have distinct global impacts. |
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