Liu G, Li X, Chiang H-W, Cheng H, Yuan S, Chawchai S, He S, Lu Y, Aung L T, Maung P M, Tun W N, Oo K M, Wang X
Interdisciplinary Graduate School, Nanyang Technological University, 639798 Singapore.
Earth Observatory of Singapore, Nanyang Technological University, 639798 Singapore.
Sci Adv. 2020 Feb 12;6(7):eaay8189. doi: 10.1126/sciadv.aay8189. eCollection 2020 Feb.
While Asian monsoon (AM) changes have been clearly captured in Chinese speleothem oxygen isotope (δO) records, the lack of glacial-interglacial variability in the records remains puzzling. Here, we report speleothem δO records from three locations along the trajectory of the Indian summer monsoon (ISM), a major branch of the AM, and characterize AM rainfall over the past 180,000 years. We have found that the records close to the monsoon moisture source show large glacial-interglacial variability, which then decreases landward. These changes likely reflect a stronger oxygen isotope fractionation associated with progressive rainout of AM moisture during glacial periods, possibly due to a larger temperature gradient and suppressed plant transpiration. We term this effect, which counteracts the forcing of glacial boundary conditions, the moisture transport pathway effect.
虽然中国洞穴石笋氧同位素（δO）记录清晰地捕捉到了亚洲季风（AM）的变化，但记录中缺乏冰期 - 间冰期变化仍然令人费解。在此，我们报告了沿着亚洲季风的一个主要分支——印度夏季风（ISM）轨迹的三个地点的洞穴石笋δO记录，并描绘了过去18万年的亚洲季风降雨情况。我们发现，靠近季风水分源的记录显示出较大的冰期 - 间冰期变化，然后向内陆逐渐减小。这些变化可能反映了与冰期期间亚洲季风水分逐渐降雨去除相关的更强的氧同位素分馏，这可能是由于更大的温度梯度和植物蒸腾作用受到抑制。我们将这种抵消冰期边界条件强迫作用的效应称为水分传输路径效应。
