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The ^Be concentration of rainwater in Kikai Island, Nansei Islands, was measured by Accelerator Mass Spectrometry (AMS). The objectives of this study are to determine the ^Be concentration of rainfall in Kikai Island and to calculate the annual precipitation rate of ^Be. The results are follows : 1) The precipitation at site. 1 always was higher than that of site. 2 through the year. Since mean annual precipitation (MAP) in Kikai Island is 2,277 mm (1966-1990), the total collected rainwater were 2,680 mm at site. 1 and 2,087 mm at site. 2,respectively, and an average of 2,384 mm, both were mostly in agreement with MAP. The difference in precipitation at site. 1 and site. 2 was due to the geomorphologic feature of sampling site. At site. 1,the air current goes up from the east side cliff, it was easy to generate fog is also sampled. 2) ^Be flux at the site. 1 tends to become higher than that of site. 2. It was recognized that ^Be flux was the highest value at the beginning of spring, and the minimum value from late summer to autumn. It suggested that the injection of stratosphere air to the troposphere at midlatitudes tended to be strong in the spring. Moreover, since loess was recognized in the sample in this period with the naked eye, it is thought that ^Be adsorbed on loess would also have influenced considerably. 3) The annual precipitation rate of ^Be was 1.77±0.29×10^6 atoms cm^ yr^ at site. 1,and 0.95±0.17×10^6 atoms cm^ yr^ at site. 2,respectively, and the average was 1.36±0.24×10^6 atoms cm^ yr^. Although this value is higher than 1.21±0.26×10^6 atoms cm^ yr^ (Monaghan et al., 1985), it can be said that it is an almost appropriate value. Although a sampling period is one year and a long-term change cannot be considered, the precipitation rate of ^Be and its seasonal change, and year change are due to continue to sampling periodically and to be clarified., 第14回名古屋大学タンデトロン加速器質量分析計シンポジウム(平成13 (2001)年度)報告

我が国の暖温帯から亜熱帯にかけて広く分布する赤黄色系土壌は、西南日本に広く分布する黄褐色森林土と本研究対象地である南西諸島に分布する赤黄色土に二大別される(Nagatsuka,1972)。南西諸島(ただし、奄美群島以南に限る) ..., 1998