南极洲因大气二氧化碳的下降而引起的快速凯诺纪冰川化
Robert M DeConto1, David Pollard
1Department of Geosciences, University of Massachusetts, Amherst, Massachusetts 01003, USA. deconto@geo.umass.edu
Nature
|January 17, 2003
概括
在伊纪/奥利古纪边界的全球冷却是由二氧化碳 (CO2) 水平下降所驱动的,而不是海洋门户的开放. 这一二氧化碳值启动了南极冰盖的快速增长,从根本上重塑了全球气候.
科学领域:
- 古气候学 古气候学
- 气候建模 气候建模
- 地质历史地质历史
背景情况:
- 埃奥森/奥利古森的边界 (大约. 3400万年前) 标志着一个重要的全球冷却事件和南极冰川形成.
- 之前的理论将这种冰期归因于南大洋门户和南极环极流的开放.
- 这种重大气候重组的确切机制和主要驱动因素仍在争论中.
研究的目的:
- 模拟东南极冰盖的形成和早期增长.
- 为了研究二氧化碳度和南洋门户在南极冰川形成中的相对作用.
- 在这个关键时期了解全球气候变化的基本驱动因素.
主要方法:
- 利用了一个全面的一般循环模型,将大气,海洋,冰盖和沉积物组成部分结合起来.
- 将古地理,温室气体度 (CO2),轨道参数和海洋热传输纳入模型.
- 在各种环境条件下模拟了冰川形成和扩张的过程.
主要成果:
- 鉴定出二氧化碳二氧化碳水平下降是南极冰川形成的主要触发因素.
- 模型模拟显示了南极高原上小冰盖的初始形成,随后是快速扩张.
- 确定了一个特定的二氧化碳值,超过这个值后,由于积极的反,冰盖的增长加速了.
- 发现,与二氧化碳度相比,南洋门户的开放起到了次要的作用.
结论:
- 该模拟支持二氧化碳的下降,是大陆冰川在伊纪/奥利古纪边界形成的主要驱动因素.
- 冰盖高度/质量平衡反和轨道变化在跨越二氧化碳值后放大了冰河形成.
- 这项研究重新评估了构造学与大气因素在重大古气候过渡中的重要性.
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