深海氧同位素5期（MIS5）黔北石笋记录的高分辨率季风突变事件及驱动机制研究

深海氧同位素5期（MIS5）处于全球冰量刚开始增大的时期（海平面比现在低20-60米），该时段全球CO2浓度较高，太阳辐射偏心率周期较强，季节性太阳辐照变化也较大。研究此边界条件下千年-数十年际尺度高低纬气候之间的联系对理解全球气候突变事件的区域响应方式及动力学机制具有极其重要的作用，同时对进一步理解全新世气候自然变化规律及未来气候预测有重要指示意义。本项目拟通过黔北三星洞石笋的高精度MC-ICP-MS测年和氧碳同位素、微量元素和稀土元素等指标的综合研究，获取MIS5高分辨率季风气候变化序列；精确标定亚洲季风间冰阶 (CIS) 25-21事件的持续时间，剖析事件转型模式和亚旋回特征；通过与南北两极冰芯记录在百年－数十年际尺度上细节对比，确立在MIS5冰量较小条件下高纬度气候和中低纬季风环流在在千年－数十年际尺度上的耦合关系，进一步探讨千年－数十年际尺度气候变率的成因机制。

During Marine Isotope Stage (MIS) 5, corresponding to sea level variations ~20-60 m below present day, atmospheric CO2 is raltively high and continent ice sheets are extending. MIS 5 is also marked by a relatively strong eccentricity and therefore large seasonal insolation changes. Full understanding of the links between two polar climate systems and Asian monsoon on the millinnial to multi-decadal scales, under conditions of extending ice sheet coverage over the high northern latitudes, is ciritical to shed light on the forcing mechanisms for abrupt climate changes. Further, it may also have important implications for understanding present climate evolution and predictions of future climate. In this study, we will present a new stalagmite-based 10-year resolution Asian monsoon record during MIS5 from Sanxing Cave, Northern Guizhou Province, China, based on several high-precision 230Th dates with a typical uncertainty of 0.3-0.5ka. Thus, our record allows an assessment of timing, transition and sub-cycles of rapid climatic switches during this period and can test the trigger-response hypothesis under conditions of little ice volume via a detailed comparion of short-lived climate events between the bipolar ice cores records and stalagmite record.