Research Article

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

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

  • Fig. 2 Correlation between Red Sea glacio-eustatic sea-level reconstruction and Sanbao Cave δ18O, on the same time scale.

    Only 10.6% of the variance in the cave isotope record is correlated with sea-level changes (1, 8). Because of different sampling intervals, 3000-year smoothing filters have been applied to each record.

  • Fig. 3 High-latitude versus low-latitude solar insolation gradient variations compared to Sanbao Cave d18O.

    (A) Plot of 65°N June solar insolation (dashed curve) (39) versus Sanbao Cave δ18O record (solid curve) (1). The δ18O scale is reversed. (B) Plot of 65°N June solar insolation (dashed curve) versus (30°N to 30°S) June solar insolation difference (solid curve). Visible are the nearly identical pattern and phase and the similar magnitude of changes.

  • Fig. 4 Intertropical seesaw: Orbitally induced changes in solar insolation mimic the seasonal interhemispheric heating-cooling cycle in the tropics and subtropics.

    (A) During boreal summer insolation maxima, Tibetan high outflow to the SISH is increased in response to two factors: (i) colder SST in the South Indian ocean, which enhances the surface anticyclone there, and (ii) earlier seasonal transition of the upper-tropospheric subtropical zonal westerly jet (24, 25) to the north side of the TP, strengthening the Tibetan high. Both factors enhance Hadley circulation and result in strengthening trade winds and Somali jet in the Indian ocean, strengthening the ISM. At the same time, outflow to the NPSH is reduced in consequence to warmer north Pacific SST, producing weaker northern trade winds and smaller onshore pressure gradient in the North Pacific, weakening the WNPSM. (B) During Boreal summer insolation minima, the opposite occurs.

Supplementary Materials

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

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

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods 
    • Figs. S1 to S7
    • Tables S1 and S2
    • References 

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