Ice core evidence on East Asian and Indian Monsoon variations during the last glacial period


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uruth [ at ] awi-bremerhaven.de

Abstract

Ice cores from central Greenland are the temporally best resolved records of northern hemisphere climate of the last glacial period. Here we show that during the last glacial period (MIS 4 to MIS 2) East Asian Monsoon variations are directly recorded in the North-GRIP ice core (north-central Greenland). The East Asian Winter Monsoon (EAWM) strength as inferred from Chinese loess deposits correlates well with the concentration and size distribution of insoluble mineral particles in the North-GRIP core, and we infer that the ice core microparticle record can be taken as a proxy for EAWM. Further, reconstructions of the Indian Summer Monsoon (ISM) strength, which controls the transport of moisture into the source regions, correlate well with the CaCO3 content at North-GRIP: e.g. the early onset of ISM after approx. 18 ka BP and the depression during MIS4, which have been inferred from East Asian loess-paleosol sequences, are also seen at NGRIP. These findings yield a new basis for ice core interpretation and put tighter constrains on the dating of Chinese loess-paleosol sequences. Finally, we take d18O as a proxy for North Atlantic temperature (NAT) and compare the timing of NAT, EAWM and ISM changes at rapid climatic transitions during the last glacial period; this can be done with high accuracy because all proxies are from the same archive and do not underlie relative dating uncertainties. We find that at rapid cold-to-warm transitions during the last glacial period EAWM changes synchronously with NAT, while ISM lags by approx. 45 years. Apart from the climatological implications this may become important for high-precision cross-dating records of NAT with East Asian records of Summer Monsoon strength such as speleothems.



Item Type
Conference (Talk)
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Not peer-reviewed
Publication Status
Published
Event Details
General Assembly of the European Geosciences Union, 24.-29.04.2005 Vienna, Austria..
Eprint ID
12149
Cite as
Ruth, U. , Roethlisberger, R. , Bigler, M. , Siggaard-Andersen, M. L. , Kipfstuhl, S. , Steffensen, J. P. , Johnsen, S. , Hansson, M. and Goto-Azuma, K. (2005): Ice core evidence on East Asian and Indian Monsoon variations during the last glacial period , General Assembly of the European Geosciences Union, 24.-29.04.2005 Vienna, Austria. .


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