轨道强迫和大气中的二氧化碳对米奥森冰盖扩张的影响
Ann Holbourn1, Wolfgang Kuhnt, Michael Schulz
1Institute of Geosciences, Christian-Albrechts-University, D-24118 Kiel, Germany. ah@gpi.uni-kiel.de
Nature
|November 25, 2005
概括
中米奥森全球冷却是由二氧化碳水平下降和南极洲的热隔离驱动的,导致冰盖的快速扩张. 这一转变标志着地球向冰川气候的转变.
科学领域:
- 古气候学 古气候学
- 气候动力学 气候动力学
- 地质海洋学 地质海洋学
背景情况:
- 中米欧纪全球冷却事件 (大约. 13,900万年前) 表示地球最终过渡到"冰"气候状态.
- 以前的假设涉及到构造循环变化和大气二氧化碳 (CO2) 变化,但缺乏强有力的沉积物证据.
- 来自亚热带太平洋的沉积物继承为重建过去气候动态提供了至关重要的档案.
研究的目的:
- 为了调查中期米奥森全球冷却和南极冰盖扩张的原因.
- 重建高分辨率的气候代理记录,用于1470万至1270万年前的时期.
主要方法:
- 来自亚热带太平洋的两个完整沉积物核心的分析.
- 使用轨道模型开发新的时间表.
- 气候代理记录的重建.
主要成果:
- 南极洲的持续,低夏季阳光照射与大气二氧化碳水平的下降相吻合.
- 南极冰盖的膨胀和全球冷却与二氧化碳的减少同时发生.
- 南极冰川的形成速度很快,发生在两个倾斜周期内.
- 在气候强迫中观察到从斜度过渡到偏心主导的转变.
结论:
- 大气中二氧化碳的减少和南极洲的热隔离可能导致了快速的冰盖形成和全球冷却.
- 在这个过渡期间,轨道偏心成为气候变化的一个更重要的驱动因素.
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