East Asian monsoon changes early in the last deglaciation and insights into the interpretation of oxygen isotope changes in the Chinese stalagmite record

Asian monsoon intensity coupled to Antarctic climate during Dansgaard–Oeschger 8 and Heinrich 4 glacial intervals

“…The former is caused by changes in the seasonal migration of the sub-tropical jet and the dominant latter one involves changes in rainout from both the Pacific and the Indian Ocean sources. Therefore, we suggest that speleothem δ 18 O represents the EASM intensity and the related precipitation, as suggested in previous studies 18,21,23,41 .…”

“…It is found that during HS intervals, the deposition rate of stalagmite was relatively low, along with strong prior calcite precipitation processes (indicated by high trace metal ratios), and the corresponding lithological section is composed of dense and fibrous minerals; these features are opposite from those during the DO Interstadials 40 . Besides, our previous review 41 on the cave records in Asia and modeling shows that two mechanisms affect stalagmite δ 18 O: changes in the fraction of monsoon rainfall in annual totals and changes in the amount of rainout between tropical sources and cave sites. The former is caused by changes in the seasonal migration of the sub-tropical jet and the dominant latter one involves changes in rainout from both the Pacific and the Indian Ocean sources.…”

“…For instance, the EASM intensity decreased during the early phase of HS1 and HS4, and then gradually increased during the second phase. Along with the phase transition, rapid monsoon weakening at 16.1 and 39.5 ka BP occurred within 20 years 41,58 and 25 years, respectively. The rapidity of the 25-year shift by 1‰ is supported by nearby annual layers at around 39 ka BP (Fig.…”

Late Quaternary Abrupt Climate Change in the Tropics and Sub‐Tropics: The Continental Signal of Tropical Hydroclimatic Events (THEs)

“…(2007) and Liang et al. (2020) and is analogous to the conclusions of Corrick et al. (2020) who compared the timing of DO events in Greenland ice with independently dated tropical stalagmite records.…”

“…Despite all of these issues, a "stacked" set of 15 IRD records from the North Atlantic shown in Figure 1 nevertheless shows remarkable temporal synchrony with proxies of THEs (though see the caveats in caption to Figure 1; Lisiecki & Stern, 2016). Within the uncertainties of dating, tropical rainfall anomalies occurred very close in time (±10 2 -10 3 yr) to the deposition of North Atlantic IRD, a conclusion which concurs with that of Jullien et al (2007) and Liang et al (2020) and is analogous to the conclusions of Corrick et al (2020) who compared the timing of DO events in Greenland ice with independently dated tropical stalagmite records.…”