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<p>The Antarctic Circumpolar Current (ACC) exerts substantial control on the physical, chemical, and biological properties of the Southern Ocean, playing a key role in modulating the global carbon cycle and climate. However, the orbital-scale forcing and future changes in the strength and position of the ACC remain elusive. Here, we reconstruct the history of ACC extending back to the Last Interglacial (LIG; 128-113 ka) using sediment cores from the Scotia Sea. Based on high-resolution measurements of sortable silt mean grain size, we find that bottom current speed is synchronized with eccentricity, superimposed by precession. During the LIG when both eccentricity and precession reached their maxima, current speed peaked in the region south of the Southern ACC front, suggesting that the Polar Front shifted ~5° southward. We propose that the low-frequency ACC frontal migration is primarily controlled by eccentricity-driven shifts in the Southern Hemisphere Westerlies, while precession-driven shifts contribute to high-frequency migration. Our findings imply under future orbital-scale scenarios, the ACC position is likely to shift north.</p>

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Extremely poleward shift of Antarctic Circumpolar Current by eccentricity during the Last Interglacial

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年10月6日

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  • Lijuan Lu,
  • Xufeng Zheng,
  • Michael E. Weber,
  • Victoria Peck,
  • Brendan T. Reilly,
  • Zhong Chen,
  • Wen Yan,
  • Tianyu Chen,
  • Hong Yan,
  • Xun Gong,
  • Shuzhuang Wu,
  • Liwei Zheng,
  • Shiming Wan,
  • Yan Du,
  • Lisa Tauxe,
  • Qinghua Yang,
  • Stefanie Brachfeld,
  • Trevor Williams,
  • Yasmina M. Martos,
  • Zhiheng Du,
  • Marga Garcia,
  • Lara F. Pérez,
  • Hu Yang,
  • Bingyue Huang,
  • Jonathan Warnock,
  • Shuh-Ji Kao

摘要

The Antarctic Circumpolar Current (ACC) exerts substantial control on the physical, chemical, and biological properties of the Southern Ocean, playing a key role in modulating the global carbon cycle and climate. However, the orbital-scale forcing and future changes in the strength and position of the ACC remain elusive. Here, we reconstruct the history of ACC extending back to the Last Interglacial (LIG; 128-113 ka) using sediment cores from the Scotia Sea. Based on high-resolution measurements of sortable silt mean grain size, we find that bottom current speed is synchronized with eccentricity, superimposed by precession. During the LIG when both eccentricity and precession reached their maxima, current speed peaked in the region south of the Southern ACC front, suggesting that the Polar Front shifted ~5° southward. We propose that the low-frequency ACC frontal migration is primarily controlled by eccentricity-driven shifts in the Southern Hemisphere Westerlies, while precession-driven shifts contribute to high-frequency migration. Our findings imply under future orbital-scale scenarios, the ACC position is likely to shift north.