Northern and southern hemisphere controls on seasonal sea surface temperatures in the Indian Ocean during the last deglaciation
Northern and southern hemisphere controls on seasonal sea surface temperatures in the Indian Ocean during the last deglaciation
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DOI：
10.1002/palo.20053
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发表时间：
2013-12
期刊：
影响因子：
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通讯作者：
Yiming V. Wang;G. Leduc;M. Regenberg;N. Andersen;T. Larsen;T. Blanz;R. Schneider
中科院分区：
文献类型：
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作者：
Yiming V. Wang;G. Leduc;M. Regenberg;N. Andersen;T. Larsen;T. Blanz;R. Schneider
除Heinrich事件1外，Mg/Ca的温度始终比Mg/Ca的温度高~ 2-3℃。此外，烯酮海温去冰变暖的初始时间开始于~15.6 ka，比Mg/Ca温度晚2.5 kyr。我们认为两种海温指标的差异反映了夏季和冬季的季节差异，而不是沉积后过程或沉积偏差。uk37年海温记录明显模拟了北大西洋地区终止期前期的消冰海温趋势，表明消冰期开始时大西洋经向翻转环流的变化可能介导了当地夏季气温的早期消冰变暖趋势。相比之下，g . rubermg /Ca记录的冰期至间冰期的海温模式可能反映了寒冷季节的海温。这表明，寒冷季节的海温可能是由南半球的气候变化介导的，因为它密切跟踪南极冰川消融的时间。因此，我们的研究表明，热带西南印度洋季节海温与两个半球的气候变化密切相关。每个代理记录的南方夏季和冬季进一步得到了我们核心站点的大气-海洋环流模式模拟的季节海温趋势的支持。我们关于烯酮和Mg/Ca海温存在季节偏差的解释也可以解释在最后一次终止开始时在其他热带地区观察到的类似代用不匹配。
37 ) are consistently warmer than those derived from Mg/Ca by ~2–3°C except for the Heinrich Event 1. In addition, the initial timing for the deglacial warming of alkenone SST started at ~15.6 ka, which lags behind that of Mg/Ca temperatures by 2.5 kyr. We argue that the discrepancy between the two SST proxies reflects seasonal differences between summer and winter rather than postdepositional processes or sedimentary biases. The U K′ 37 SST record clearly mimics the deglacial SST trend recorded in the North Atlantic region for the earlier part of the termination, indicating that the early deglacial warming trend attributed to local summer temperatures was likely mediated by changes in the Atlantic Meridional Overturning Circulation at the onset of the deglaciation. In contrast, the glacial to interglacialSSTpatternrecordedbyG.ruberMg/Ca probably reflectscoldseasonSSTs.This indicates that the cold season SSTs was likely mediated by climate changes in the southern hemisphere, as it closely tracks the Antarctic timing of deglaciation. Therefore, our study reveals that the tropical southwestern Indian Ocean seasonal SST was closely linked to climate changes occurring in both hemispheres. The austral summer and winter recorded by each proxy is further supported with seasonal SST trends modeled by Atmosphere–ocean General Circulation Models for our core site. Our interpretation that the alkenone and Mg/Ca SSTs are seasonally biased may also explain similar proxy mismatches observed in other tropical regions at the onset of the last termination.