在没有外部强迫的情况下,在合的海洋大气模拟中发生的突然气候事件
1Lamont-Doherty Earth Observatory, Palisades, New York 10964, USA. alexhall@ldeo.columbia.edu
Nature
|February 24, 2001
概括
内部大气的变化可以引发突然的气候变化. 一个15000年的全球循环模拟揭示了北大西洋的自发冷却事件,由风驱动,而不是淡水强迫.
科学领域:
- 气候科学 气候科学
- 古气候学 古气候学
- 海洋学 海洋学 海洋学
背景情况:
- 北大西洋气候重建显示,在冰川和全新纪期间,频繁出现突然波动.
- 以前的气候模型需要淡水强迫来模拟这样的事件.
- 这些快速气候变化的根本驱动因素仍然不清楚.
研究的目的:
- 调查大气内部变化的潜力,以推动北大西洋的气候急剧波动.
- 在没有外部强迫的情况下模拟剧烈的冷却事件.
主要方法:
- 使用当今气候条件进行了15,000年全球循环模拟.
- 分析了自发气候事件及其驱动因素的模拟输出.
主要成果:
- 在格陵兰南部附近发生了自发的严重冷却事件,持续了30-40年,温度低于平均值6-10个标准偏差.
- 该事件是由持续的西北风引发的,它将冷淡的淡水运送到北大西洋.
- 海洋对流关闭,局部冷却在上层海洋层.
结论:
- 仅仅是内部大气的变化就能在北大西洋产生极端的气候干扰.
- 模拟结果与观察到的快速冷却事件记录一致.
- 这表明,过去没有外部触发因素的气候突然变化的潜在机制.
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