A detailed comparison of Asian Monsoon intensity and Greenland temperature during the Allerod and Younger Dryas events

作者:Liu Dianbing; Wang Yongjin*; Cheng Hai; Edwards R Lawrence; Kong Xinggong; Wang Xianfeng; Wu Jiangying; Chen Shitao
来源:Earth and Planetary Science Letters, 2008, 272(3-4): 691-697.
DOI:10.1016/j.epsl.2008.06.008

摘要

An annual layer-counted and (230)Th-dated stalagmite oxygen isotope record from Qingtian Cave in Hubei province, central China, provides an Asian Monsoon (AM) history across the Allerod to Younger Dryas (YD) transition, with an average 2.5-year resolution. Seasonal delta(18)O profiles indicate that the calcite delta(18)O is a sensitive proxy for AM changes, and the close similarity between the Qingtian and other cave records from eastern China suggests a large-scale regional coherence of monsoonal precipitation delta(18)O variations associated with the temperature changes in high-northern latitudes. The annually-resolved chronology with a U-Th age uncertainty of less than 100 yr defines the timing, duration and transition of the early Allerod, the intra-Allerod cold period (IACP). the late Allerod, and the start of the YD. The 160-yr-long IACP, with two brief reversals, is clearly shown in both 5'80 and lamina thickness records. The early and late Allerod, separated by the IACP, are characterized by several decadal to centennial cycles of delta(18)O variations, each punctuated by sub-cycles. These decadal to centennial monsoon variations correlate with the Greenland temperature changes, supporting a model simulation that the decadal North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO) are coupled via atmospheric circulation under glacial boundary conditions, perhaps affecting tropical/subtropical monsoon changes. However, the monsoon transition between the late Allerod and YD lasted 380 yr, longer than the analogous Greenland temperature shift by at least 130 yr [Stuiver, M., Grootes, P.M., GISP2 oxygen isotope ratios. Quat. Res. 53 (2000) 277-284]. This implicates other links besides the direct link between Greenland and the AM, which is now well documented. One possibility is the influence by Southern Hemisphere climate via cross-equatorial air flow [An, Z.S., The history and variability of the East Asian paleomonsoon climate. Quat. Sci. Rev. 19 (2000) 171-187].