RECONSTRUCTION OF MILLENNIAL-SCALE VARIATIONS IN THE EAST ASIAN SUMMER MONSOON OVER THE PAST 300 KA BASED ON THE TOTAL CARBON CONTENT OF SEDIMENT FROM LAKE BIWA, JAPAN

Abstract

The total carbon content analysis for Takashima-oki core extracted from Lake Biwa with time resolutions of approximately 150 years was used to reconstruct millennial-scale climate change in the East Asian monsoon region over the past 300 ka. The total carbon content of the Takashima-oki 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 ~1,500-year cycle that is also recorded by paleoclimate indices in the North Atlantic region. We propose that the East Asian summer monsoon underwent abrupt millennium-scale changes during interglacial stages such as MIS 5 and 7.