Reconstruction of millennialscale variations in t

Authors: Naoya Iwamoto Yoshio Inouchi

Publish Date: 2007/01/04

Volume: 52, Issue: 8, Pages: 1607-1616

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Abstract

The total carbon content analysis for Takashimaoki core extracted from Lake Biwa with time resolutions of approximately 150 years was used to reconstruct millennialscale climate change in the East Asian monsoon region over the past 300 ka The total carbon content of the Takashimaoki core is an indirect proxy for the East Asian summer monsoon because the total carbon content reflects primary productivity within the lake which is controlled by precipitation in the catchment area Using these data we clarify temporal variations in the East Asian summer monsoon prior to MIS 5 which were previously unresolved The observed variations show a ∼1500year cycle that is also recorded by paleoclimate indices in the North Atlantic region We propose that the East Asian summer monsoon underwent abrupt millenniumscale changes during interglacial stages such as MIS 5 and 7The authors are grateful to Mr S Yokota formerly of the Geological survey of Japan for analyzing the CN content of the Takashimaoki core and teaching us the method of biogenic silica analysis and Prof F Kumon Shinshu University and Prof S Yoshikawa Osaka City University for helpful academic advice

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