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Titel |
Southern Hemisphere imprint for Indo-Asian summer monsoons during the last glacial period as revealed by Arabian Sea productivity records |
VerfasserIn |
T. Caley, S. Zaragosi, J. Bourget, P. Martinez, B. Malaizé, F. Eynaud, L. Rossignol, Thierry Garlan, N. Ellouz-Zimmermann |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 10, no. 11 ; Nr. 10, no. 11 (2013-11-15), S.7347-7359 |
Datensatznummer |
250085419
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Publikation (Nr.) |
copernicus.org/bg-10-7347-2013.pdf |
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Zusammenfassung |
The monsoon is one of the most important climatic phenomena: it promotes
inter-hemispheric exchange of energy and affects the economical prosperity of
several countries exposed to its seasonal seesaw. Previous studies in both
the Indian and Asian monsoon systems have generally suggested a dominant
northern hemispheric (NH) control on summer monsoon dynamics at the scale of
suborbital–millennial climatic changes, while the forcing/response of Indian
and Asian monsoons at the orbital scale remains a matter of debate. Here, six
marine sediment cores distributed across the whole Arabian Sea are used to
build a regional surface marine productivity signal. The productivity signal
is driven by the intensity of Indian summer monsoon winds. Our results
demonstrate the existence of an imprint of suborbital southern hemispheric
(SH) temperature changes (i.e. Antarctica) on the Indian summer monsoon
during the last glacial period that is generally not recognized. During the
last deglaciation, the NH played a more significant role. This suggests that
fluctuations in the Indian monsoon are better explained in a bipolar context.
The δ18O signal recorded in the Asian monsoon speleothem records
could be exported by winds from the Indian summer monsoon region, as recently
proposed in modelling exercise, explaining the SH signature observed in Asian
cave speleothems. Contrary to the view of a passive response of Indian and
Asian monsoons to NH anomalies, the present results appear to suggest that
the Indo-Asian summer monsoon plays an active role in amplifying millennial
inter-hemispheric asymmetric patterns. Additionally, this study confirms
previously observed differences between Indian and Asian speleothem monsoonal
records at the orbital-precession scale. |
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