Coupling of Indo-Pacific climate variability over the last millennium
Coupling of Indo-Pacific climate variability over the last millennium
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DOI：
10.1038/s41586-020-2084-4
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发表时间：
2020-03-09
期刊：
影响因子：
64.8
通讯作者：
Heslop, David
中科院分区：
文献类型：
--
作者：
Abram, Nerilie J.;Wright, Nicky M.;Heslop, David
珊瑚记录表明，印度洋偶极子在过去一千年的变化与厄尔尼诺/南方涛动的变化密切相关，最近的极端事件是不寻常的，但并非前所未有。印度洋偶极子（IOD）影响世界各地的气候和降雨，在印度洋周边国家影响最严重（1-4）。正IOD事件的频率和强度在二十世纪增加（5），并可能在变暖的世界中继续加强（6）。然而，由于IOD模型中已知的偏差（7）以及缺乏关于人为气候变化之前IOD自然变化的信息，对未来IOD变化预测的信心受到限制。在这里，我们使用精确的日期和高分辨率的珊瑚记录从赤道东印度洋，IOD的变化的签名是强大的和明确的，产生一个半连续的重建IOD的变化，涵盖了五个世纪的最后一个千年。我们的重建表明，极端积极的IOD事件是罕见的1960年之前。然而，有记录的最极端的事件（1997年）并非史无前例，因为至少有一个比它大27%至42%的事件发生在世纪。我们进一步表明，一个持久的，紧密的耦合之间存在的变化IOD和厄尔尼诺/南方涛动在过去的千年。印度洋-太平洋耦合的特点是在大约1590年之前的年际变化较弱，这可能改变了遥相关模式，而在17世纪期间的年际变化非常强，这与热带亚洲的社会动荡有关。在我们的重建中，正IOD事件的聚类趋势是明显的，这与极端IOD变化和持续的热带印度洋-太平洋气候耦合的识别一起，可能对改善季节性和十年期预测和管理未来IOD变化的气候风险有影响。
Coral records indicate that the variability of the Indian Ocean Dipole over the last millennium is strongly coupled to variability in the El Nino/Southern Oscillation and that recent extremes are unusual but not unprecedented.The Indian Ocean Dipole (IOD) affects climate and rainfall across the world, and most severely in nations surrounding the Indian Ocean(1-4). The frequency and intensity of positive IOD events increased during the twentieth century(5) and may continue to intensify in a warming world(6). However, confidence in predictions of future IOD change is limited by known biases in IOD models(7) and the lack of information on natural IOD variability before anthropogenic climate change. Here we use precisely dated and highly resolved coral records from the eastern equatorial Indian Ocean, where the signature of IOD variability is strong and unambiguous, to produce a semi-continuous reconstruction of IOD variability that covers five centuries of the last millennium. Our reconstruction demonstrates that extreme positive IOD events were rare before 1960. However, the most extreme event on record (1997) is not unprecedented, because at least one event that was approximately 27 to 42 per cent larger occurred naturally during the seventeenth century. We further show that a persistent, tight coupling existed between the variability of the IOD and the El Nino/Southern Oscillation during the last millennium. Indo-Pacific coupling was characterized by weak interannual variability before approximately 1590, which probably altered teleconnection patterns, and by anomalously strong variability during the seventeenth century, which was associated with societal upheaval in tropical Asia. A tendency towards clustering of positive IOD events is evident in our reconstruction, which-together with the identification of extreme IOD variability and persistent tropical Indo-Pacific climate coupling-may have implications for improving seasonal and decadal predictions and managing the climate risks of future IOD variability.