Stable isotope measurements of water from fluid inclusions in Stalagmites on Okinawa Island

为了了解地球的气候系统，有必要获得过去气候和环境变化的信息。在这个项目中，我们专注于流体包裹体的石笋，这是希望保存同位素比值的“过去的降水”。我们发展了一种测量流体包裹体中水的氢氧同位素比值的方法。氧同位素比值在降水变化范围内。然而，需要改进的精度和准确度来重建过去的温度变化。此外，我们在冲绳进行了洞穴滴水和降水同位素比率的观测。结果表明，水汽输送过程的差异导致了同位素比值的明显季节变化。

In order to understand Earth's climate system, it is necessary to obtain information on past climate and environmental changes. In this project, we focused on fluid inclusions in the stalagmite, which is expected to preserve isotope ratios of "past precipitation". We have developed a method to measure the hydrogen and oxygen isotope ratios of water in fluid inclusions. Oxygen isotope ratio was within the range of variation of precipitation. However, improved precision and accuracy are needed to reconstruct the past temperature variations. In addition, we conducted observation of drip water in caves and precipitation isotope ratios on Okinawa Island. The results showed that a clear seasonal variation of isotope ratios caused by the differences in water vapor transport processes.