North Atlantic forcing of tropical Indian Ocean climate
North Atlantic forcing of tropical Indian Ocean climate
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DOI：
10.1038/nature13196
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发表时间：
2014-05-01
期刊：
影响因子：
64.8
通讯作者：
Lueckge, Andreas
中科院分区：
文献类型：
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作者：
Mohtadi, Mahyar;Prange, Matthias;Lueckge, Andreas
印度洋地区热带气候对北大西洋突发气候变化事件的反应是有争议的。热带辐合带的重新定位被认为是北大西洋寒潮期间热带水文气候变化的原因（1-5），但印度洋季风领域以外高分辨率记录的缺乏阻碍了对这种遥远关系及其潜在机制的充分理解。本文表明，海因里希时期和新仙女木时期大西洋经向翻转环流的减缓通过哈德利环流的变化影响了热带印度洋的水文气候，包括上升分支（热带辐合带）的南移和南印度洋上空的整体减弱。我们的研究结果基于过去45000年热带东印度洋沉积档案的新的高分辨率海面温度和海水氧同位素记录，并结合海洋同位素阶段2和3边界条件下大西洋环流减缓的气候模式模拟。盆地东部和西部的类似条件排除了纬向偶极子结构作为千年尺度事件中热带印度洋水文气候的主导强迫。我们的模拟和代理数据的结果表明，在北大西洋寒潮期间，北印度洋区域处于干燥状态，而南印度洋区域处于湿润和温暖状态。
The response of the tropical climate in the Indian Ocean realm to abrupt climate change events in the North Atlantic Ocean is contentious. Repositioning of the intertropical convergence zone is thought to have been responsible for changes in tropical hydroclimate during North Atlantic cold spells(1-5), but the dearth of high-resolution records outside the monsoon realm in the Indian Ocean precludes a full understanding of this remote relationship and its underlying mechanisms. Here we show that slowdowns of the Atlantic meridional overturning circulation during Heinrich stadials and the Younger Dryas stadial affected the tropical Indian Ocean hydroclimate through changes to the Hadley circulation including a southward shift in the rising branch (the intertropical convergence zone) and an overall weakening over the southern Indian Ocean. Our results are based on new, high-resolution sea surface temperature and seawater oxygen isotope records of well-dated sedimentary archives from the tropical eastern Indian Ocean for the past 45,000 years, combined with climate model simulations of Atlantic circulation slowdown under Marine Isotope Stages 2 and 3 boundary conditions. Similar conditions in the east and west of the basin rule out a zonal dipole structure as the dominant forcing of the tropical Indian Ocean hydroclimate of millennial-scale events. Results from our simulations and proxy data suggest dry conditions in the northern Indian Ocean realm and wet and warm conditions in the southern realm during North Atlantic cold spells.