500万年南极环极电流的强度变化
Frank Lamy1,2, Gisela Winckler3,4, Helge W Arz5
1Alfred Wegener Institute (AWI) Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany. Frank.Lamy@awi.de.
Nature
|March 28, 2024
概括
南极环极流 (ACC) 没有显示全球冷却的线性趋势. 相反,ACC强度反转,与气候周期联系在一起,并可能随着未来的变暖而增加.
科学领域:
- 古代海洋学
- 气候科学
- 海洋学
背景情况:
- 南极环极流 (ACC) 对全球海洋循环,气候调节和南极冰盖的稳定性至关重要.
- 过去的ACC动态因地区而异,但其长期演变仍不清楚.
- 目前的ACC行为受到大气强迫,海洋密度和活动的影响.
研究的目的:
- 重建ACC强度的长期变化
- 研究 ACC 演变与全球气候变化之间的关系.
- 了解数百万年时间尺度上的ACC变化的驱动因素.
主要方法:
- 分析来自南太平洋的沉积物核心.
- 在过去的530万年中,ACC强度的重建.
- 与古气候记录的相关性,包括全球冷却和冰量.
主要成果:
- 自530万年前以来, ACC强度没有出现线性趋势, 尽管全球变冷.
- 发生了ACC强度的逆转:在世冷却过程中增加,然后随着世早期冷却而减少.
- ACC强度的变化与40万年偏心周期和南大洋重构有关.
- 冰川时期较弱的ACC流,石沉积变化和降低的CO2之间的持续联系出现于普莱斯托时代中期过渡后.
结论:
- 而不是对全球变暖的简单反应.
- 南洋的重新配置改变了ACC对气候强化的敏感性.
- 最强的ACC流量发生在温暖的Plio-Pleistocene间隔,这表明随着变暖而增加的可能性.
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