Li Xusheng, Zhou Yuwen, Han Zhiyong, Yuan Xiaokang, Yi Shuangwen, Zeng Yuqiang, Qin Lisha, Lu Ming, Lu Huayu
School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China.
Nat Commun. 2024 Feb 3;15(1):1023. doi: 10.1038/s41467-024-45379-9.
The cycle of precipitation change is key to understanding the driving mechanism of the East Asian summer monsoon (EASM). However, the dominant cycles of EASM precipitation revealed by different proxy indicators are inconsistent, leading to the "Chinese 100 kyr problem". In this study, we examine a high-resolution, approximately 350,000-year record from a low-latitude loess profile in China. Our analyses show that variations in the ratio of dithionite-citrate-bicarbonate extractable iron to total iron are dominated by the ~20-kyr cycle, reflecting changes in precipitation. In contrast, magnetic susceptibility varies with the ~100-kyr cycle and may be mainly controlled by temperature-induced redox processes or precipitation-induced signal smoothing. Our results suggest that changes in the EASM, as indicated by precipitation in this region, are mainly forced by precession-dominated insolation variations, and that precipitation and temperature may have varied with different cycles over the past ~350,000 years.
降水变化周期是理解东亚夏季风（EASM）驱动机制的关键。然而，不同代用指标揭示的东亚夏季风降水主导周期并不一致，从而导致了“中国10万年问题”。在本研究中，我们考察了来自中国一个低纬度黄土剖面的高分辨率、约35万年的记录。我们的分析表明，连二亚硫酸盐 - 柠檬酸盐 - 碳酸氢盐可提取铁与总铁的比值变化主要受约20 kyr周期的控制，反映了降水的变化。相比之下，磁化率随约100 kyr周期变化，可能主要受温度诱导的氧化还原过程或降水诱导的信号平滑作用控制。我们的结果表明，该地区降水所指示的东亚夏季风变化主要受岁差主导的日照变化驱动，并且在过去约35万年里，降水和温度可能随不同周期而变化。
