闽西岩溶系统氧同位素传输机制及对ENSO的响应

中国季风区石笋氧同位素记录已经成为全球古气候记录对比的基石之一。然而，学术界对中国季风区石笋氧同位素信号的解译还存在颇多争议。岩溶系统现代过程监测和近现代石笋记录与器测资料对比是了解石笋氧同位素指示意义最为直接有效的途径。我国东南福建地区位于东亚夏季风影响的前沿地带，受热带海洋气候变化的影响较大，是研究ENSO等调控季风气候的理想地区。本项目选择闽西将乐玉华洞和赖源仙云洞开展洞穴现代过程监测和近现代季节性高分辨率记录重建研究。通过多个水文年的大气降水-洞穴滴水-新生成次生碳酸盐沉积物氧同位素传递过程研究，结合季节-年际高分辨率石笋氧同位素记录，与器测资料、水汽来源、季风指数和ENSO等进行对比，分析水汽来源/ENSO等对区域大气降水和滴水的δ18O的影响机制，明确我国东南地区湿润亚热带典型季风区石笋氧同位素的指代意义。同时探究洞穴滴水点δ18O对台风信号响应的敏感性。

Chinese stalagmite δ18O records have became the benchmark for comparison of global paleoclimate records. However, the interpretation of δ18O remains in argument. Comprehensive study on caves monitoring and stalagmite record is an effective method to accurately understand the speleothem δ18O significance. Taking the regional advantages of Southeast China as the frontier of East Asian summer monsoon, we will carry out a multi-year on-site monitoring program on the modern process of karst system in 2 caves in western Fujian Province. By studying the process of oxygen isotope transfer in meteoric precipitation, cave drip water, and newly formed calcite, and combing the correlation between high-resolution stalagmite δ18O record with local temperature and rainfall, moisture source, monsoon index, and ENSO, etc, we will analyze the influence mechanism of water vapor source/ENSO on the regional atmospheric precipitaiton and water drip in caves. Moreover, we will uncover the significance of stalagmite δ18O in typical humid subtropical monsoon area in Southeastern China. Furthermore, we will explore the sensitivity of drip water to Typhoon signals.