The variation of summer monsoon precipitation in central China since the last deglaciation
The variation of summer monsoon precipitation in central China since the last deglaciation
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末次冰消期以来华中地区夏季风降水变化
DOI：
10.1016/j.epsl.2009.12.039
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发表时间：
2010-03-01
影响因子：
5.3
通讯作者：
Wang, Xianfeng
中科院分区：
文献类型：
--
作者：
Cai, Yanjun;Tan, Liangcheng;Wang, Xianfeng
对采自陕西省酒仙洞的两个石笋（C996-1和C996-2）进行了铀系定年和稳定同位素分析。38个Th-230测年结果表明，石笋C996-1在8.5kaBP（距今1000年，距今约1950年）以来持续沉积，C996-2在19 kaBP（8.3 ~ 5.7kaBP和15.4 ~ 11.9kaBP）以来沉积，不包括两个生长间断期。相对稳定的边界条件下，我们解释的三角洲O-18的洞穴方解石的夏季季风降水量的指示，虽然温度和其他因素可能有一些轻微的影响。三角洲O-18记录显示，末次盛冰期（LGM）期间，东亚季风气候发生了显著变化，这与葫芦洞和三宝洞的记录相似，表明在末次盛冰期期间，北至秦岭的东亚地区都发生了显著的季风气候变化。与同期洞穴记录的对比表明，在低纬季风区，即霍德洞，O-18三角洲的上升趋势最早开始于7.5kaBP左右，而在高纬度地区，O-18三角洲的上升趋势出现得较晚，如东阁洞与7.0kaBP相似，和尚洞与5.3kaBP相似，与三宝洞4.7kaBP和酒仙洞4.5kaBP相似。这些结果表明，全新世东亚夏季风降水的变化是异步的。这可能与热带-副热带耦合季风系统对太阳辐射变化的响应和热力强迫的差异有关，而热力强迫的差异是由复杂的地理结构造成的。热带西太平洋海表温度（SST）的变化也可能对我国中部和北方夏季风降水的变化产生重要影响，因为它影响着作为季风锋调节器的西北太平洋副热带高压。需要更可靠的测试来证实这一现象，并详细评估不同因素的影响。(c)2010 Elsevier B. V.保留所有权利。
Two stalagmites (C996-1 and C996-2) collected from the Jiuxian Cave in the Shaanxi Province in central China have been studied with U-series dating and stable isotope analysis. Thirty-eight Th-230 dating results showed that the stalagmite C996-1 was continuously deposited through the last 8.5 ka BP (thousand years before present, present=1950 AD), and C996-2 was deposited through the last 19 ka BP excluding two growth hiatuses between 8.3 and 5.7 ka BP, and 15.4 and 11.9 ka BP. With a relatively stable boundary condition, we interpret the delta O-18 of speleothem calcite as most indicative of the amount of summer monsoon precipitation, although temperature and other factors might have some minor impact. The delta O-18 records show notable changes within the last glacial maximum (LGM), resembling other East Asian monsoon records such as those from the Hulu and Sanbao Caves, suggesting that significant monsoonal climate changes occurred in eastern Asia as far north as the Qinling Mountains during the LGM interval A comparison of our. records to precisely dated contemporaneous speleothem records from other caves shows that the increasing trend of delta O-18 during the Holocene commenced as early as similar to 7.5 ka BP in the low-latitude monsoonal area, i.e. the Hod Cave, while at higher latitudes this shift occurred later, such as similar to 7.0 ka BP in the Dongge Cave, similar to 5.3 ka BP in the Heshang Cave, similar to 4.7 ka BP in the Sanbao Cave and similar to 4.5 ka BP in the Jiuxian Cave. These results imply an asynchronous change of the summer monsoon precipitation occurred in East Asia during the Holocene. The asynchrony may be related to the responses of a coupled tropical and subtropical monsoon system to changes of the insolation and the differences in thermal forcing, which result from the complex geographical configuration. The variation of sea surface temperature (SST) in the western tropical Pacific may also have important impacts on the summer monsoon precipitation changes in central and northern China because it affects the Northwestern Pacific Subtropical High, a monsoon-front regulator. More robust tests are needed to confirm this phenomenon and to evaluate the contribution of different factors in detail. (c) 2010 Elsevier B.V. All rights reserved.