Asian summer monsoon precipitation recorded by stalagmite oxygen isotopic composition in the western Loess Plateau during AD1875―2003 and its linkage with ocean-atmosphere system  

作　　者：LIU JingHua ZHANG PingZhong CHENG Hai CHEN FaHu YANG XunLin ZHANG DeZhong ZHOU Jing JIA JiHong AN ChunLei SANG WenCui Kathleen R. JOHNSON 

机构地区：[1]Key Laboratory of Western China's Environmental System of Ministry of Education, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China [2]Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455, USA [3]School of Geographical Sciences, Southwest University, Chongqing 400715, China [4]Department of Earth System Science, University of California, Irvine, CA 92697, USA

出　　处：《Chinese Science Bulletin》2008年第13期2041-2049,共9页

基　　金：the National Natural Science Foundation of China (NSFC) (Grant No.40471137);the Innovation Team Project of the NSFC (Grant No.40421101);Doctor Station Foundation,Ministry of Education of China (Grant No.20040730025)

摘　　要：Based on 5 high-precision 230Th dates and 103 stable oxygen isotope ratios (δ18O) obtained from the top 16 mm of a stalagmite collected from Wanxiang Cave,Wudu,Gansu,variation of monsoonal precipita-tion in the modern Asian Monsoon (AM) marginal zone over the past 100 years was reconstructed. Comparison of the speleothem δ18O record with instrumental precipitation data at Wudu in the past 50 years indicates a high parallelism between the two curves,suggesting that the speleothem δ18O is a good proxy for the AM strength and associated precipitation,controlled by "amount effect" of the pre-cipitation. Variation of the monsoonal precipitation during the past 100 years can be divided into three stages,increasing from AD 1875 to 1900,then decreasing from AD 1901 to 1946,and increasing again thereafter. This variation is quite similar to that of the Drought/Flooding index archived from Chinese historical documents. This speleothem-derived AM record shows a close association with the Pacific Decadal Oscillation (PDO) between AD 1875 and 1977,with higher monsoonal precipitation corre-sponding to cold PDO phase and vice versa at decadal timescale. The monsoonal precipitation varia-tion is out of phase with the PDO after AD 1977,probably resulting from the decadal climate jump in the north Pacific occurring at around AD 1976/77. These results demonstrate a strong linkage between the AM and associated precipitation and the Pacific Ocean via ocean/atmosphere interaction. This rela-tionship will aid to forecast future hydrological cycle for the AM monsoon region,and to improve forecasting potential of climatic model with observation data from cave.Based on 5 high-precision ^230Th dates and 103 stable oxygen isotope ratios （51eO） obtained from the top 16 mm of a stalagmite collected from Wanxiang Cave, Wudu, Gansu, variation of monsoonal precipitation in the modern Asian Monsoon （AM） marginal zone over the past 100 years was reconstructed. Comparison of the speleothem δ^18O record with instrumental precipitation data at Wudu in the past 50 years indicates a high parallelism between the two curves, suggesting that the speleothem δ^18O is a good proxy for the AM strength and associated precipitation, controlled by ＂amount effect＂ of the precipitation. Variation of the monsoonal precipitation during the past 100 years can be divided into three stages, increasing from AD 1875 to 1900, then decreasing from AD 1901 to 1946, and increasing again thereafter. This variation is quite similar to that of the Drought/Flooding index archived from Chinese historical documents. This speleothem-derived AM record shows a close association with the Pacific Decadal Oscillation （PDO） between AD 1875 and 1977, with higher monsoonal precipitation corresponding to cold PDO phase and vice versa at decadal timescale. The monsoonal precipitation variation is out of phase with the PDO after AD 1977, probably resulting from the decadal climate jump in the north Pacific occurring at around AD 1976/77. These results demonstrate a strong linkage between the AM and associated precipitation and the Pacific Ocean via ocean/atmosphere interaction. This relationship will aid to forecast future hydrological cycle for the AM monsoon region, and to improve forecasting potential of climatic model with observation data from cave.

关 键 词：石笋 同位素 季风 降水 

分 类 号：P42[天文地球—大气科学及气象学]