Role of Asian summer monsoon subsystems in the inter-hemispheric progression of deglaciation
Role of Asian summer monsoon subsystems in the inter-hemispheric progression of deglaciation
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DOI：
10.1038/s41561-019-0319-5
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发表时间：
2019-03
影响因子：
18.3
通讯作者：
K. Nilsson-Kerr;P. Anand;P. F. Sexton;M. J. Leng;M. J. Leng;Sambuddha Misra;S. Clemens;S. J. Hammond
中科院分区：
文献类型：
--
作者：
K. Nilsson-Kerr;P. Anand;P. F. Sexton;M. J. Leng;M. J. Leng;Sambuddha Misra;S. Clemens;S. J. Hammond
亚洲季风子系统对半球气候强迫和外轨道强迫的响应目前是激烈争论的问题。印度夏季季风是能量通量中占主导地位的季风子系统，是地球上海洋与大气相互作用最动态的表现形式之一。然而，印度夏季季风在亚洲季风古气候记录中的代表性严重不足。在这里，我们展示了 139-127 万年前印度夏季季风引起的降雨和河流径流的高分辨率记录，这些记录是在 139-127 万年前孟加拉湾的沉积岩芯中恢复的，包括对表层海洋有孔虫的氧同位素组成和 Mg/Ca、Mn/Ca、Nd/Ca 和 U/Ca 比率的耦合测量。我们的数据揭示了亚洲季风的千禧年规模短暂加强，其间断了与双极跷跷板振荡相关的第二次季风终止。冰消变暖的进展首先出现在南半球，然后伴随着印度夏季季风的加强出现在热带地区，最后出现在北半球。因此，我们认为印度夏季风是南半球潜热向北输送的通道，从而促进了随后的北半球冰川消融。
The responses of Asian monsoon subsystems to both hemispheric climate forcing and external orbital forcing are currently issues of vigorous debate. The Indian summer monsoon is the dominant monsoon subsystem in terms of energy flux, constituting one of Earth’s most dynamic expressions of ocean–atmosphere interactions. Yet, the Indian summer monsoon is grossly under-represented in Asian monsoon palaeoclimate records. Here, we present high-resolution records of Indian summer monsoon-induced rainfall and fluvial runoff recovered in a sediment core from the Bay of Bengal across Termination II, 139–127 thousand years ago, including coupled measurements of the oxygen isotopic composition and Mg/Ca, Mn/Ca, Nd/Ca and U/Ca ratios in surface-ocean-dwelling foraminifera. Our data reveal a millennial-scale transient strengthening of the Asian monsoon that punctuates Termination II associated with an oscillation of the bipolar seesaw. The progression of deglacial warming across Termination II emerges first in the Southern Hemisphere, then the tropics in tandem with Indian summer monsoon strengthening, and finally the Northern Hemisphere. We therefore suggest that the Indian summer monsoon was a conduit for conveying Southern Hemisphere latent heat northwards, thereby promoting subsequent Northern Hemisphere deglaciation.