西南季风区石笋氧同位素信号气候意义及2 ka以来快速气候变化研究

石笋氧同位素 气候快速变化事件 洱海 西南季风区 高分辨率
黄林培 2014-01 项目
The climatic significance of stalagmite δ18O from China monsoon area still remains unclear. High-resolution comparative study between stalagmite δ18O and other climate proxies from same area is the key to this issue. In this proposal, we focus on the stalagmite from Jinsuo island of Erhai. A high-resolution record of stalagmite δ18O will be obtained according to the combination of layer counting and U-Th dating. By comparative study with modern meteorological data and lacustrine records from Erhai, the climatic significance of stalagmite δ18O in southwest monsoon area will be discussed. Base on the above findings, a stalagmite δ18O record with annual to seasonal resolution during the last 2000 years will be established. The characteristics of key abrupt climate change events such as Medieval Warm Period, Little Ice Age and Current Warm Period will be analyzed in detail. Furthermore, by comparing with records of marine sediment, ice core and stalagmite δ18O from other area of East Asian, we will investigate the controlling factor and mechanism of abrupt climate change and our results could provide important evidence for future abrupt climate predication under similar climate backgrounds.
中国季风区石笋氧同位素信号的本质至今仍存在许多争议,寻找同一地区不同气候代用指标的高分辨率对比研究是解决问题的关键和途径之一。本项目以洱海金梭岛上洞穴石笋为研究对象,开展石笋年纹层计年、高分辨率U-Th测年和稳定同位素测定获得年际-季际石笋稳定同位素变化序列,通过与现代气象观测资料以及已有洱海湖泊沉积记录的高分辨率对比研究,初步探讨典型西南季风区石笋氧同位素信号的气候意义。在明确石笋氧同位素气候意义的基础上,建立分辨率达年际甚至季节尺度的近2000年来石笋氧同位素序列,对中世纪暖期、小冰期和现代高温期等气候快速变化事件进行精确厘定,并与海洋沉积、高纬冰芯以及东亚其他地区石笋等典型记录分别进行变化趋势和变化细节分析,探讨气候快速变化事件内部气候格局差异的原因及其与全球气候变化的关系,探索影响气候快速变化的控制因素及变化机理。