北大西洋的千年级气候变化记录为50万年的记录
1Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA. Salem State College, Salem, MA 01970, USA.
概括
海洋沉积物记录显示,当冰盖超过关键尺寸值时,北大西洋气候不稳定性会放大. 这导致了更大的海面温度波动,并在冰川时期增加了冰山排放量.
科学领域:
- 古气候学 古气候学
- 海洋学 海洋学 海洋学
- 冰川学的冰川学
背景情况:
- 来自亚极北大西洋的海洋沉积物记录提供了对过去气候动态的见解.
- 在过去的50万年里,千年规模的气候变化一直是北大西洋地区的一个特征.
- 冰盖的大小在调节区域气候不稳定性方面起着至关重要的作用.
研究的目的:
- 调查冰盖大小与区域气候不稳定性之间的关系.
- 为了确定冰盖增长的关键值,这些值会引发气候变化.
- 分析海面温度和冰山排放模式的变化.
主要方法:
- 从亚极北大西洋长,连续的海洋沉积物核心的分析.
- 检查本土氧同位素 (delta18O) 值以表明冰盖的大小.
- 对冰山排放和海面温度波动的指标的评估.
主要成果:
- 确定了冰盖大小的临界值,以每毫米3.5的delta18O值表示.
- 超过这一门,海面温度和冰山排放的千年级变化显著增加.
- 海面温度波动从1-2°C放大到4-6°C,频繁出现大量冰山排放.
结论:
- 冰盖的大小是扩大北大西洋千年气候变化的关键因素.
- 与现代冰盖配置相比,相对较小的变化达到确定不稳定性值.
- 全新纪冰川间期代表了一个稳定的气候状态,超出了冰川期间观察到的放大不稳定的范围.
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