A 550,000-year record of East Asian monsoon rainfall from 10Be in loess


Beck, J. Warren
Zhou, Weijian
Li, Cheng
Wu, Zhenkun
White, Lara; Xian, Feng; Kong, Xianghui An; Zhisheng

Cosmogenic 10Be flux from the atmosphere is a proxy for rainfall. Using this proxy, we derived a 550,000-year-long record of East Asian summer monsoon (EASM) rainfall from Chinese loess. This record is forced at orbital precession frequencies, with higher rainfall observed during Northern Hemisphere summer insolation maxima, although this response is damped during cold interstadials. The 10Be monsoon rainfall proxy is also highly correlated with global ice-volume variations, which differs from Chinese cave δ18O, which is only weakly correlated. We argue that both EASM intensity and Chinese cave δ18O are not governed by high-northern-latitude insolation, as suggested by others, but rather by low-latitude interhemispheric insolation gradients, which may also strongly influence global ice volume via monsoon dynamics.

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Fig. 1
10Be-proxy EASM rainfall versus Sanbao Cave d18O, sea level, and benthic foraminiferal d18O records. (A) Plot of 10Be-based rainfall (red) versus Sanbao δ18O record (yellow). The δ18O scale is reversed. 65°N June insolation (dashed curve) is also shown (8) for reference. Locations of some MIS stages are labeled below (C). MIS stages 5b,c and 7b are missing from our profile (supplementary materials). (B) Plot of 10Be-based rainfall (red) versus Red Sea glacio-eustatic sea level curve (blue) relative to modern sea level (8), both placed on Sanbao Cave age models. Main glacial terminations (vertical gray bars) are labeled below this figure. (C) Plot of 10Be-based rainfall (red) versus LR04 stacked benthic δ18O curve (blue) (9).

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Science 25 May 2018: Vol. 360, Issue 6391, pp. 877-881 DOI: 10.1126/science.aam5825