普利奥-普莱斯托时代的冰体积,南极气候,以及全球18O三角洲的记录
M E Raymo1, L E Lisiecki, Kerim H Nisancioglu
1Department of Earth Science, Boston University, 685 Commonwealth Avenue, Boston, MA 02215, USA. raymo@bu.edu
概括
两个半球的冰体积变化都受到当地的夏季阳光照射的控制. 大约100万年前,南极洲以海洋为基础的冰盖的转移同步了北半球和南半球的冰盖.
科学领域:
- 古气候学 古气候学
- 冰川学的冰川学
- 地球系统科学 地球系统科学
背景情况:
- 地球半球的冰体积波动表现出与轨道强迫的复杂相互作用.
- 全球集成的代理像海洋delta18O和海平面都受到相位和相位外轨道组件的影响.
研究的目的:
- 为了研究北半球和南半球的驱动因素,在300万年前到100万年前之间的冰体积变化.
- 为了解释41000年倾斜周期在古气候记录中的占主导地位.
- 为了阐明中普莱斯托时代过渡的原因和23000年周期的加强.
主要方法:
- 分析古气候代理数据,包括海洋三角洲18O和海平面记录.
- 冰盖动态的建模及其对阳光强迫的反应.
- 北半球和南半球冰体积行为的比较.
主要成果:
- 每个半球的冰体积变化主要由当地的夏季阳光照射控制.
- 半球之间的非相前行周期 (23,000年) 导致了全球代理的取消.
- 一个适度的南极冰块质量变化可能会抵消北半球更大的信号.
- 普莱斯托时代中期的过渡涉及转向以海洋为基础的南极冰盖,同步半球行为并加强了23000年的周期性.
结论:
- 当地夏季阳光照射,而不是全球,在研究期间推动了半球冰体积变化.
- 南极洲以海洋为基础的冰盖的过渡从根本上改变了冰盖的动态和古气候周期性.
- 观察到的模式解释了旧记录中倾斜强迫的主导地位,以及过渡后出现更强的前进信号.
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