A 500,000 year record of Indian summer monsoon dynamics recorded by eastern equatorial Indian Ocean upper water-column structure
A 500,000 year record of Indian summer monsoon dynamics recorded by eastern equatorial Indian Ocean upper water-column structure
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DOI：
10.1016/j.quascirev.2013.07.031
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发表时间：
2013-10-01
影响因子：
4
通讯作者：
Zhao, Xiang
中科院分区：
文献类型：
--
作者：
Bolton, Clara T.;Chang, Liao;Zhao, Xiang
印度夏季风（ISM）是一个跨半球和高度可变的海洋-大气-陆地相互作用，直接影响人口稠密的印度次大陆。在这里，我们提出了新的记录的古海洋学的变化，跨越过去50万年的东赤道印度洋，一个相对采样不足的地区ISM的影响。我们已经产生了碳和氧稳定同位素记录，从三个有孔虫物种从大洋钻探计划网站758（5度N，90度E），以调查该地区的海洋历史。我们解释我们得到的三角洲三角洲O-18（表面温跃层）记录的上层水柱分层的背景下，过去的ISM变化，并比较轨道相位关系在我们的网站758数据的其他气候和季风代理在该地区。结果表明，在站点758，这是占主导地位的岁差和半岁差频率（23，19和11万年）的方差，上层水柱分层是由当地（5度N）的日照和ISM风。在岁差（23 ka）带，分层最小在站点758滞后北方半球夏季日照最大值（岁差最小值）9 ka，这是一致的阿拉伯海ISM阶段的估计，并建议在这两个地区共同的风强迫。这一阶段意味着一个强大的敏感性，冰量和南半球的太阳辐射强迫通过潜热输出从南亚热带印度洋。此外，我们发现在我们的分层记录，这表明远程突然的气候事件对ISM动态的影响可能叠印的千年尺度的事件在冰川终止的证据。(C)2013爱思唯尔有限公司保留所有权利。
The Indian Summer Monsoon (ISM) is an inter-hemispheric and highly variable ocean atmosphere land interaction that directly affects the densely populated Indian subcontinent. Here, we present new records of palaeoceanographic variability that span the last 500,000 years from the eastern equatorial Indian Ocean, a relatively under-sampled area of ISM influence. We have generated carbon and oxygen stable isotope records from three foraminiferal species from Ocean Drilling Program Site 758 (5 degrees N, 90 degrees E) to investigate the oceanographic history of this region. We interpret our resultant Delta delta O-18 (surface-thermocline) record of upper water-column stratification in the context of past ISM variability, and compare orbital phase relationships in our Site 758 data to other climate and monsoon proxies in the region. Results suggest that upper water-column stratification at Site 758, which is dominated by variance at precession and half-precession frequencies (23,19 and 11 ka), is forced by both local (5 degrees N) insolation and ISM winds. In the precession (23 ka) band, stratification minima at Site 758 lag northern hemisphere summer insolation maxima (precession minima) by 9 ka, which is consistent with Arabian Sea ISM phase estimates and suggests a common wind forcing in both regions. This phase implicates a strong sensitivity to both ice volume and southern hemisphere insolation forcing via latent heat export from the southern subtropical Indian Ocean. Additionally, we find evidence of possible overprinting of millennial-scale events during glacial terminations in our stratification record, which suggests an influence of remote abrupt climate events on ISM dynamics. (C) 2013 Elsevier Ltd. All rights reserved.