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基于黄土高原西部甘肃武都万象洞中一根石笋0～16mm之间的5个高精度230Th年代和103个δ18O数据,重建了亚洲季风边缘区过去100多年来高分辨率的季风降水变化历史.通过与武都器测降水数据对比发现,最近50多年来石笋氧同位素组成受降雨量效应的影响,指示了亚洲季风的强弱变化及其带来的降水量信息.近100多年来亚洲季风的变化历史可分为季风降水增强期(AD1875～1900)、季风降水减弱期(AD1901～1946)和季风降水再次增强期(AD1947～2003)3个气候段,而且这3个季风变化阶段与通过历史文献记载建立的旱涝指数变化相似.近100多年来万象洞石笋氧同位素记录的季风强度变化与太平洋年代际振荡(PDO)密切相关,年代际时间尺度上PDO暖(冷)相位与季风降水的减少(增加)对应;但在1977年之后出现了季风降水变化和PDO的反相位关系,很可能是北太平洋在1976/1977年前后发生的年代际气候跃变的反映.说明现代亚洲季风强度及季风降水变化通过海气相互作用与太平洋密切相关.这种关系将有助于亚洲季风区水循环的预测,而且可以利用洞穴观测数据来提高气候模型的预测能力。
Based on five high-precision 230Th and 103 δ18O data from 0 to 16 mm of a stalagmite in the Vientiane Cave, Wudu, Wusu, Gansu, western Loess Plateau, a high-resolution monsoon precipitation history over the past 100 years in the Asian monsoon margin has been reconstructed. Comparing with the Wudu data, it is found that the oxygen isotopic composition of stalagmite in the past 50 years has been affected by the rainfall effect, which indicates the change of the intensity of the Asian monsoon and the precipitation. The change of the Asian monsoon over the past 100 years The history can be divided into three climatic periods: the period of enhanced monsoon precipitation (AD1875 ~ 1900), the period of monsoon precipitation weakened (AD1901 ~ 1946) and the period of enhanced monsoonal precipitation (AD1947 ~ 2003), and the three monsoon stages The changes of drought and flood index were similar in the past 100 years.The change of monsoon intensity recorded by the oxygen isotopes of stalagmite in the Vientiane Cave in recent 100 years was closely related to the Pacific Decadal Oscillation (PDO). The PDO warm phase and the monsoon precipitation decreased on the decadal time scale (Increase); however, after 1977, the monsoon precipitation change and the anti-phase relationship of PDO appeared, which is likely to be the interdecadal gas in the North Pacific around 1976/77 Which indicates that the change of the monsoon intensity and the monsoon precipitation in modern Asia are closely related to the Pacific Ocean through the interaction of the sea and air.The relationship will contribute to the prediction of the water cycle in the Asian monsoon region and may utilize the cave observation data to improve the climate model Ability to predict.