Japan Geoscience Union Meeting 2016

Presentation information

Poster

Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS14] Atmospheric Electricity

Mon. May 23, 2016 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL6)

Convener:*Kazuhiko Miura(Faculty of Science, Tokyo University of Science), Masashi Kamogawa(Department of Physics, Tokyo Gakugei University)

5:15 PM - 6:30 PM

[MIS14-P02] Measurements of radon and thoron decay products at Tarobo, a base of Mt. Fuji, Japan

*Kazuhiko Miura1, Naoki Kawaguchi1, Toshiaki Sudo1, Ryota Kataoka1, Yoko Iwamoto1, Katsuhiro Nagano2, Hiroshi Hayami3 (1.Faculty of Science, Tokyo University of Science, 2.Faculty of Science and Technology, Tokyo University of Science, 3.Central Research Institute of Electric Power Industry)

Keywords:radon thoron decay products, seasonal variation, Mt. Fuji

The atmospheric activity concentrations of the short-lived radon and thoron decay products were measured at Tarobo (1300 m a.s.l.), a base of Mt. Fuji, from July 2014 to Aug. 2015. Radon and thoron concentrations were calculated with energy spectra of arfa-ray emitted from radioactive aerosols collected on a filter with a time resolution of 2 or 4 h by using a radon monitor. In addition, size distributions of aerosols from about 10 nm to 5000 nm in diameter were measured with a scanning mobility particle sizer and an optical particle counter. In order to estimate the history of air masses, the backward trajectories from 72 h ago to 48 h ago were computed using the HYSPLIT trajectory model (https://ready.arl.noaa.gov/HYSPLIT_traj.php).
Clear seasonal variations of total counts of decay products were found that monthly averaged values were high between autumn and winter, and low between spring and summer. On the other hand, diurnal variations were not observed clearly. It is supposed that the cause of seasonal variations is due to the deference of air mass. These patterns were compared with the results measured at Jungfraujoch (Gaggeler, et al., 1995).
Acknowledgments
This work was partly supported by JSPS KAKENHI Grant Number 25340017.
References
Gaggeler, H. W. et al., Atmospheric Environment, 29, 607-616, 1995