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| Titel |
Timing and magnitude of equatorial Atlantic surface warming during the last glacial bipolar oscillation |
| VerfasserIn |
S. Weldeab |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 8, no. 5 ; Nr. 8, no. 5 (2012-10-26), S.1705-1716 |
| Datensatznummer |
250005850
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| Publikation (Nr.) |
 copernicus.org/cp-8-1705-2012.pdf |
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| Zusammenfassung |
| The timing and magnitude of millennial-scale thermal oscillation in
the equatorial Atlantic during the last glacial and marine isotope
stage 3 have been perceived as merely a response to
meltwater-induced perturbations of the northern high latitude
climate. The relatively asymmetric distribution of available
temperature records has so far impeded testing whether this view is
valid across the equatorial Atlantic. This study presents a
centennially resolved record of Mg/Ca-derived sea surface
temperature (SST) estimates from the eastern equatorial Atlantic
(EEA) and a core top-based proxy validation. Multivariate analysis
of the EEA core top data indicates that the Mg/Ca ratio varies by
8 ± 2% per unit SST (°C) and 1 ± 0.9% per
unit salinity (psu) change, indicating that temperature is the
most dominant factor controlling planktonic foraminiferal Mg/Ca
variation. The EEA SST time series exhibits a close correlation
between episodes of rapid equatorial surface water warming, the
onset of massive meltwater inputs into the North Atlantic (Heinrich
events H3–H6), and Antarctic climate changes, indicating that the
EEA was very sensitive to millennial-scale bipolar oscillations.
Rapid EEA SST rise between 0.8 °C and 2 °C,
synchronous with the onset of Heinrich events, is consistent with
the concept of tropical Atlantic warming in response to
meltwater-induced perturbation of Atlantic meridional ocean
circulation (AMOC). At variance with model results that suggest a
basin-wide SST rise during and rapid surface cooling concomitant
with the termination of Heinrich events, this study indicates
persistently elevated EEA SST during and up to 2300 yr after the
abrupt termination of Heinrich events. This study emphasizes that changes in wind-induced low-latitude
zonal surface currents were crucial in shaping the spatial
heterogeneity and duration of equatorial Atlantic surface water
warmth. |
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