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| Titel |
Thermal variations at the Southern Margin of the Western Pacific Warm Pool over the past 340 kyrs |
| VerfasserIn |
Sheng Pu Chang, Chuan-Chou Shen |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250052321
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| Zusammenfassung |
| The global climate change is strongly influenced by the evolution of Western Pacific Warm
Pool (WPWP), which is one of the most important sources of heat and moisture to the mid- to
high-latitude regions. However, the detailed glacial-interglacial dynamics of the WPWP and
the driving forcings are still not clear. For better understanding the mechanism, we measured
Mg/Ca ratios of planktonic foraminifera, Globigerinoides ruber (250-300 μm) of a sediment
core MD05-2925 (9Ë 20.61’S, 151Ë 27.61’E) over the past 340 thousand years in the
southern margin of the WPWP (SMWP). Low ratios of Al/Ca and Mn/Ca and a shallow
water depth of 1642 m indicate no detectable high magnesium contamination from
ferromanganese oxide and clay minerals, little dissolution effect, and corroborate the
validity of Mg/Ca thermometry. The determined G. ruber Mg/Ca record shows
an averaged low glacial value of 3.4-3.6 mmol/mol and high interglacial value of
4.8-5.0 mmol/mol. The glacial-interglacial variation is about 1.3-1.6 mmol/mol. The
Mg/Ca-inferred SST data show the glacial SST of 24-25 Ë C, 3-4 Ë C lower than the
interglacial temperature of 27-28 Ë C. A maximum SST, 28-29 Ë C, was observed at
the MIS 5e. Compared with the records of the central warm pool (CWP) (Lea et
al., 2000), remarkable features are: (1) the averaged SST difference between the
CWP and SMWP is 2.5 Ë C during the glacial period while the difference is only
~1.0 Ë C during MIS 1, 5, and 7; (2) at the MIS 5e, SMWP SST was 1 Ë C higher
than that in the Holocene and no SST gradient is found between CWP and SMWP;
and (3) the SMWP SST record is characterized with a clear 21-kyr periodicity.
Accordingly, we speculate that the WPWP could evolve with an interglacial expansion and
a glacial contraction, associated with the variability of northern solar insolation. |
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