Details

Autor(en) / Beteiligte

• 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.

Titel

Variability of stalagmite-inferred Indian monsoon precipitation over the past 252,000 y

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 2015-03, Vol.112 (10), p.2954-2959

Ort / Verlag

United States: National Academy of Sciences

Erscheinungsjahr

2015

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• A speleothem δ ¹⁸O 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. Significance This paper presents a new long speleothem δ ¹⁸O time series from Xiaobailong cave in southwest China that characterizes changes in a major branch of Indian summer monsoon precipitation over the last 252 kyrs. This record shows not only 23-kyr precessional cycles punctuated by prominent millennial-scale weak monsoon events synchronous with Heinrich events in the North Atlantic, but also clear glacial–interglacial variations that are consistent with marine records but different from the cave records in East China. The speleothem records of Xiaobailong and other caves in East China show that the relationship between the Indian and the East Asian summer monsoon precipitation is not invariant, but rather varies on different timescales depending on the nature and magnitude of the climate forcing.