中科院地球环境研究所周卫健和安芷生课题组的最新研究报道了，在过去870 kyr偏心率调制地磁场和季风降雨的变化。2023年4月17日，国际知名学术期刊《美国科学院院刊》发表了这一成果。

课题组人员展示了中国中部黄土高原黄土-古土壤序列，在过去870 kyr 中¹⁰Be引起的地磁场和亚洲季风(AM)降水的变化。与全球记录同步，¹⁰Be_GM 通量(地磁场诱导的¹⁰Be产生率的代理)揭示了Brunhes期内13个连续的地磁偏移事件，为中国黄土-古土壤序列提供了关键的时间标志。

¹⁰Be的降水显示，明显的约100 kyr 冰期-间冰期旋回，以及叠加的进动(约23 kyr)旋回，与中国洞穴堆积物 δ¹⁸O的记录相一致。研究强调，地磁场和亚洲季风降水的变化有一个共同的约100 kyr 的周期性，这意味着地磁场和气候可能都由偏心率调制。

据介绍，地磁场和地球轨道参数之间是否存在联系仍存在争议。平行的长期定量地磁场和气候变化记录的同步重建也很少见。

附：英文原文

Title: Eccentricity-paced geomagnetic field and monsoon rainfall variations over the last 870 kyr

Author: Zhou, Weijian, Kong, Xianghui, Paterson, Greig A., Sun, Youbin, Wu, Yubin, Ao, Hong, Xian, Feng, Du, Yajuan, Tang, Ling, Zhou, Jie, Shi, Zhengguo, Jull, A. J. Timothy, Zhao, Guoqing, An, Zhisheng

Issue&Volume: 2023-4-17

Abstract: Whether there are links between geomagnetic field and Earth’s orbital parameters remains unclear. Synchronous reconstructions of parallel long-term quantitative geomagnetic field and climate change records are rare. Here, we present ¹⁰Be-derived changes of both geomagnetic field and Asian monsoon (AM) rainfall over the last 870 kyr from the Xifeng loess–paleosol sequence on the central Chinese Loess Plateau. The ¹⁰Be_GM flux (a proxy for geomagnetic field-induced ¹⁰Be production rate) reveals 13 consecutive geomagnetic excursions in the Brunhes chron, which are synchronized with the global records, providing key time markers for Chinese loess–paleosol sequences. The ¹⁰Be-derived rainfall exhibits distinct ~100 kyr glacial–interglacial cycles, and superimposed precessional (~23 kyr) cycles that match with those in Chinese speleothem δ¹⁸O record. We find that changes in the geomagnetic field and AM rainfall share a common ~100 kyr cyclicity, implying a likely eccentricity modulation of both the geomagnetic field and climate.

DOI: 10.1073/pnas.2211495120

Source: https://www.pnas.org/doi/10.1073/pnas.2211495120