在最后一个冰川最大期期间减少了厄尔尼诺-南方振荡
Heather L Ford1, A Christina Ravelo2, Pratigya J Polissar3
1Ocean Sciences Department, University of California, Santa Cruz, CA 95064, USA. Biology and Paleo Environment, Lamont-Doherty Earth Observatory, Palisades, NY 10964, USA. hford@ldeo.columbia.edu.
概括
厄尔尼诺-南方振荡 (ENSO) 在最后的冰川最大期显示出由于深度热流线而减少的变化,这表明它不仅仅是由温度梯度驱动的.
科学领域:
- 古气候学 古气候学
- 海洋学 海洋学 海洋学
- 气候科学 气候科学
背景情况:
- 厄尔尼诺-南方振荡 (ENSO) 是全球气候变化的关键驱动力.
- 了解ENSO对过去气候变化的反应,例如最后的冰川最大值 (LGM),对于预测未来气候至关重要.
- 以前的假设将ENSO的变化直接与东西温度梯度联系起来.
研究的目的:
- 为了重建赤道太平洋的LGM海面温度.
- 为了研究在LGM边界条件下的ENSO行为.
- 重新评估ENSO变化的主要驱动因素.
主要方法:
- 对单个浮游生物的分析,用于温度重建.
- 从赤道太平洋沉积物核心收集古气候数据.
- 将LGM ENSO变异性与晚期全新纪录进行比较.
主要成果:
- LGM赤道太平洋温度显示出一个深层热流线.
- 这种深层热流线显著改变了东方赤道冷舌区域的海洋动态.
- 与晚期Holocene相比,LGM期间ENSO变异性明显减少.
结论:
- 在LGM期间,ENSO的变化并不是由东西温度梯度直接控制的.
- 一个深东赤道太平洋热链在调节ENSO对LGM气候条件的反应中发挥了关键作用.
- 这些发现完善了我们对ENSO对全球边界条件的敏感性的理解.
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