Modern stalagmite oxygen isotopic composition and its implications of climatic change from a high-elevation cave in the eastern Qinghai-Tibet Plateau over the past 50 years
Modern stalagmite oxygen isotopic composition and its implications of climatic change from a high-elevation cave in the eastern Qinghai-Tibet Plateau over the past 50 years
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DOI：
10.1007/s11434-007-0166-4
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发表时间：
2007-05
影响因子：
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通讯作者：
Xunlin Yang;Pingzhong Zhang;Fahu Chen;C. Huh;Hong-chun Li;Hai Cheng;K. Johnson;Jinghua Liu;C. An
中科院分区：
文献类型：
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作者：
Xunlin Yang;Pingzhong Zhang;Fahu Chen;C. Huh;Hong-chun Li;Hai Cheng;K. Johnson;Jinghua Liu;C. An
青藏高原东部黄龙洞石笋的230Th和210Pb氧同位素记录提供了近50年来亚洲季风的变化，平均分辨率为1年。研究表明，洞内滴水的δ 18 O代表当地大气降水的年平均δ 18 O，石笋是在同位素平衡下沉积的。石笋δ18O记录与仪器气象资料的对比表明，δ18O的变化主要受西南季风（印度季风）输送的大气降水量效应的控制，受温度的影响较小。因此，δ 18 O记录的变化反映了季风降水在西南季风影响下的年际时间尺度变化。黄龙洞石笋的δ 18O记录与亚洲季风区许多石笋的δ18O记录一样，在近50年来也呈现出逐渐富集的趋势，即相对富集。这种趋势可能表明亚洲季风强度的下降，这与季风指数的下降是一致的。现代亚洲季风的减弱与平流层温度的变化有很好的对应关系，说明季风的减弱主要是由于太阳辐射的减少。
An oxygen isotope record of a stalagmite from Huanglong Cave in the eastern Qinghai-Tibet Plateau dated with230Th and210Pb methods provides variations of the Asian monsoon with an average resolution of 1 year over the past 50 years. This study shows that theδ18O of dripwater in the cave represents the annual meanδ18O of local meteoric precipitation and the stalagmites were deposited in isotopic equilibrium. A comparison of the stalagmiteδ18O record with instrumentally meteorological data indicates that shifts of theδ18O are largely controlled by the amount effect of meteoric precipitation conveyed through the southwest monsoon (the Indian monsoon) and less affected by temperature. Therefore, the variations ofδ18O record reflect the changes in monsoon precipitation on inter-annual time scales under the influence of the southwest monsoon. Like many other stalagmiteδ18O records in the Asian monsoon regions, theδ18O record of the stalagmite from Huanglong Cave also reveals a gradually enriched trend during the past 50 years, i.e. relatively enriched in18O. This trend may indicate the decline of the Asian monsoon intensity which is consistent with the decrease of monsoon indices. The weakening of the modern Asian monsoon well matched with the temperature changes in stratosphere, which may illustrate that the weakening of the monsoon mainly results from the lowering of solar radiation.