闽西石笋记录的末次冰期千年尺度气候突变事件研究

The climate over the last glacial period was characterized by a series of abrupt, millennial and sub-millennial climate oscillations known as Greenland InterStadial/Stadial (GIS/GS) events and Heinrich (H) events. Absolutely dated records of comparable high resolution with bipolar ice cores records are a prerequisite to better understand the forcing mechanisms in the climate system. Here we present a new high resolved oxygen isotope record in western Fujian province, Southeast China, covering the last glacial period between 71 and 14 ka BP. These new data allows us to investigate the timing, duration, structure and sub-cycles of both GIS and H events in unprecedented detail. We will compare our record with the bipolar ice cores records and the other independent-dated cave records in Asian monsoon areas to evaluate the spatial and temporal pattern of these abrupt climate changes during the last glacial period and explore the driving mechanisms of North high hemisphere climate, low latitude tropical hydroclimate, and South ocean thermal reservoir in influencing the East Aisan summer monsoon abrupt climate changes.

末次冰期千年尺度气候突变事件的高分辨率重建有助于理解气候边界条件(太阳辐射、冰量、温室气体等)、高低纬相互作用以及海气耦合过程等对突变事件的制约。本项目拟通过我国东南闽西地区湿润亚热带典型东亚季风区洞穴石笋研究，重建末次冰期71~14 ka BP季风突变事件的高分辨率记录，确定气候突变事件的持续时间、转型模式及其亚旋回特征。通过与南北极冰芯记录和亚洲季风区不同区域记录的对比，评估北高纬气候、低纬热带水文循环和南大洋潜热效应等对气候突变事件的贡献，探讨东亚季风千年尺度气候突变事件的驱动机制。

末次冰期千年尺度气候突变事件的高分辨率重建有助于理解气候边界条件(太阳辐射、冰量、温室气体等)、高低纬相互作用以及海气耦合过程等对突变事件的制约。本项目通过我国东南闽西仙云洞石笋研究，重建了末次冰期典型时段60-14kyr BP期间季风突变事件的高分辨率记录，重点分析了典型气候突变事件的转型特征。与中国北方石笋记录对比发现，在典型的CIS事件开始阶段，东亚季风区呈现北方快速和东南缓变的两种模式。对比分析结果表明，中国北方的突变模式主要通过西风带受控于北高纬气候，而东南缓变模式主要受低纬西太平洋海气耦合的影响。