在俄罗斯北北北极地区记录的普略纪温暖,极地放大和渐进的普略纪冷却
Julie Brigham-Grette1, Martin Melles, Pavel Minyuk
1Department of Geosciences, University of Massachusetts, 611 North Pleasant Street, Amherst, MA 01003, USA. juliebg@geo.umass.edu
概括
北极的夏季在普略纪时期显著更温暖,即使二氧化碳水平较低. 这项研究提供了关键的北极气候数据,揭示了导致第一个冰河时代的逐渐冷却趋势.
科学领域:
- 古气候学 古气候学
- 北极气候动态 北极气候动态
- 地质时间尺度地质时间尺度.
背景情况:
- 由于缺乏连续的,高分辨率的北极时间序列,对过去的气候演变的理解有限.
- 从温暖的普略世到早期冰川周期的过渡不太清楚.
研究的目的:
- 为了重建北极气候的演变,在中期的普略纪到早期的普纪.
- 为了解过去的气候变化提供高分辨率的北极时间序列.
主要方法:
- 利用来自俄罗斯北北北极的El'gygytgyn湖的多代理证据.
- 分析了沉积物核心,用于古气候重建.
主要成果:
- 中纪 (3.6-3.4万年) 北极夏季比今天温暖8°C,碳排放量为400ppm.
- 有证据表明,在纪中期出现了极端的高温和极地放大.
- 在世-普世过渡期间发生了突然的冷却事件.
- 在北半球冰川开始后,北极的夏季一直比现在更温暖,直到大约2亿2千万年前.
结论:
- 北极的冷却不足以支持大型冰盖,直到世早期.
- 这些发现与海平面记录和其他代理数据一致.
- 这项研究增强了对北极气候敏感性和冰川形成的理解.
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