过去25.2万年里石笋推断的印度季风降水变化
Variability of stalagmite-inferred Indian monsoon precipitation over the past 252,000 y.
作者信息
Cai Yanjun, Fung Inez Y, Edwards R Lawrence, An Zhisheng, Cheng Hai, Lee Jung-Eun, Tan Liangcheng, Shen Chuan-Chou, Wang Xianfeng, Day Jesse A, Zhou Weijian, Kelly Megan J, Chiang John C H
机构信息
State Key Lab of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China; Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China;
Center for Atmospheric Sciences, University of California, Berkeley, CA 94720;
出版信息
Proc Natl Acad Sci U S A. 2015 Mar 10;112(10):2954-9. doi: 10.1073/pnas.1424035112. Epub 2015 Feb 23.
A speleothem δ(18)O record from Xiaobailong cave in southwest China characterizes changes in summer monsoon precipitation in Northeastern India, the Himalayan foothills, Bangladesh, and northern Indochina over the last 252 kyr. This record is dominated by 23-kyr precessional cycles punctuated by prominent millennial-scale oscillations that are synchronous with Heinrich events in the North Atlantic. It also shows clear glacial-interglacial variations that are consistent with marine and other terrestrial proxies but are different from the cave records in East China. Corroborated by isotope-enabled global circulation modeling, we hypothesize that this disparity reflects differing changes in atmospheric circulation and moisture trajectories associated with climate forcing as well as with associated topographic changes during glacial periods, in particular redistribution of air mass above the growing ice sheets and the exposure of the "land bridge" in the Maritime continents in the western equatorial Pacific.
中国西南部小白龙洞的洞穴次生碳酸盐氧同位素（δ(18)O）记录描绘了过去25.2万年期间印度东北部、喜马拉雅山麓、孟加拉国和印度支那北部夏季风降水的变化。该记录以2.3万年的岁差周期为主，其间穿插着与北大西洋 Heinrich 事件同步的显著千年尺度振荡。它还显示出明显的冰期 - 间冰期变化，这与海洋和其他陆地 proxy 数据一致，但与中国东部的洞穴记录不同。通过同位素驱动的全球环流模型证实，我们推测这种差异反映了与气候强迫以及冰川期相关地形变化有关的大气环流和水汽轨迹的不同变化，特别是在不断增长的冰盖上方气团的重新分布以及赤道太平洋西部海洋大陆“陆桥”的暴露。
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