不同轨道背景下湖北永兴洞石笋年轮的年-年代际气候变率研究

将器测时期年-年代际气候变率的研究扩展到更老的冰期旋回，可以深入认识太阳辐射、CO2浓度、冰量变化等不同轨道背景对短尺度气候变率的控制机理。本项目选择湖北永兴洞25万年来不同轨道气候背景下连续生长数百-千年的6个石笋年轮序列，开展石笋纹层机理和气候学研究。结合8年现代洞穴监测，研究4个典型时段（间冰期、冰期、冰消期、间冰期/冰期转换时段）石笋纹层特征，探讨石笋年轮的结晶生长机理和对外部气候因子的响应规律。在此基础上，研究最近两个冰期/间冰期旋回4个典型时段连续生长数百-千年的多指标石笋记录，获得不同气候背景下的年际-年代际气候变化特征和振荡规律。结合现代亚洲年际-年代际气候变率的观察和模拟的研究成果，分析不同边界条件下亚洲季风年际-年代际气候变率的动力学机制。本项目研究结果为深入认识当今全球变暖季风特征和未来演化提供基础数据，并有助于完善石笋年轮的年代学和气候学的理论和方法。

Extending the study of the interannual- to decadal-timescale climate variabilities from the instrumental period to older glacial cycles provides insights into the control mechanisms of short-timescale climate variabilities under different orbital backgrounds, such as solar radiation, CO2 concentrations, and ice volume changes. In this project, annual microlayer sequences derived from six stalagmites that grew continuously for hundreds to thousands of years during the past 250,000 years in Yongxing Cave, Hubei Province, were selected to carry out stalagmite lamination mechanism and climatological research. Combined with the eight-year modern cave monitoring, we are going to study the lamination characteristics of stalagmite in four typical periods (Interglacial, Glacial, Deglacial and Interglacial /Glacial transition), and discuss the crystal growth mechanism of stalagmite annual layers and their response to external climate factors. On this basis, these continuously-deposited and multi-proxy stalagmite records during the last two glacial/interglacial cycles are used to obtain the interannual-interdecadal climate characteristics and oscillation patterns under different climate backgrounds. Combined with results from the observation and simulation of modern interannual-interdecadal Asian climate variabilities, the dynamics of the interannual-interdecadal Asian monsoon variabilities under different boundary conditions will be analyzed. This project aims to provide basic data for an in-depth understanding of current monsoon characteristics in the global warming condition and its future evolution, and helps to improve the theories and methodologies of "Stalagmite microlayer Chronology and Climatology".