Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation
Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation
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DOI：
10.1038/nclimate2554
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发表时间：
2015-05-01
影响因子：
30.7
通讯作者：
Schaffernicht, Erik J.
中科院分区：
文献类型：
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作者：
Rahmstorf, Stefan;Box, Jason E.;Schaffernicht, Erik J.
大西洋经向翻转环流(AMOC)的可能变化是未来气候变化不确定性的一个关键来源。二十世纪的温度趋势图显示了北大西洋一个明显的降温区域。在这里，我们提出了多种证据，表明这种降温可能是由于20世纪特别是1970年后AMOC的减少所致。自1990年以来，AMOC似乎部分恢复了元气。基于海洋表面温度的AMOC指数、半球温差、基于珊瑚的替代物和海洋测量结果一致地表明了这一时间演变。我们讨论了格陵兰冰盖融化对经济放缓的可能贡献。对AMOC指数使用多指标温度重建表明，1975年之后AMOC的疲软是过去千年中前所未有的事件(p>；0.99)。未来几十年格陵兰岛的进一步融化可能会进一步削弱AMOC。
Possible changes in Atlantic meridional overturning circulation (AMOC) provide a key source of uncertainty regarding future climate change. Maps of temperature trends over the twentieth century show a conspicuous region of cooling in the northern Atlantic. Here we present multiple lines of evidence suggesting that this cooling may be due to a reduction in the AMOC over the twentieth century and particularly after 1970. Since 1990 the AMOC seems to have partly recovered. This time evolution is consistently suggested by an AMOC index based on sea surface temperatures, by the hemispheric temperature difference, by coral-based proxies and by oceanic measurements. We discuss a possible contribution of the melting of the Greenland Ice Sheet to the slowdown. Using a multi-proxy temperature reconstruction for the AMOC index suggests that the AMOC weakness after 1975 is an unprecedented event in the past millennium (p > 0.99). Further melting of Greenland in the coming decades could contribute to further weakening of the AMOC.