冰川气候通过淡水排放和海洋循环的强烈半球合
R Knutti1, J Flückiger, T F Stocker
1Climate and Environmental Physics, Physics Institute, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland. knutti@climate.unibe.ch
Nature
|August 20, 2004
概括
在最后一个冰川时期的气候变化是由海洋循环变化驱动的. 淡水排放到北大西洋直接影响南大洋的温度,支持修订的双极波动气候模型.
科学领域:
- 古气候学 古气候学
- 海洋学 海洋学 海洋学
- 气候建模 气候建模
背景情况:
- 在最后一个冰川时期,千年规模的气候变化引发了北半球突然变暖和南极温度变化放缓.
- 海洋热环流 (THC) 的破坏被广泛认为是这种气候变化的原因.
- 全球海平面也随着这些气候变化而变化.
研究的目的:
- 调查北大西洋淡水排放对南大洋温度的直接影响.
- 阐明驱动双极气候动态的机制及其与海平面变化的关系.
- 提出一个扩展和定量双极摇摆概念.
主要方法:
- 利用一个合的海洋-大气-海冰模型.
- 模拟淡水排放到北大西洋.
- 分析了海洋热传输和密度梯度.
主要成果:
- 淡水排放到北大西洋,加上减少的THC,直接影响南大洋的温度.
- 异常向南的海洋热传输起源于亚热带北大西洋的区域密度梯度.
- 该模型成功地解释了格陵兰岛和南极洲温度变化的时间和幅度,以及南极温度与海平面的相似性.
结论:
- 该研究为双极摇摆机制提供了定量框架,将北大西洋和南大洋的气候动态联系起来.
- 它强调了北大西洋淡水脉冲对全球气候模式的直接影响.
- 这些发现提供了关于海洋循环,极地温度和冰川时期的海平面变化之间的复杂相互作用的见解,包括在海洋同位素阶段3期间潜在的海平面滞后.
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