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Earth Planets Space, Vol. 57 (No. 2), pp. e5-e8, 2005

E-LETTER

A new technique of radiation thermometry using a consumer digital camcorder: Observations of red glow at Aso volcano, Japan

Takeshi Saito1, Satoshi Sakai2, Isao Iizawa2, Eriko Suda3, Kazuhiro Umetani2, Katsuya Kaneko2, Yoshitsugu Furukawa4, and Takahiro Ohkura4

1Institute for Geothermal Sciences, Graduate School of Science, Kyoto University, Noguchibaru, Beppu, Oita 874-0903, Japan
2Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-Nihon-Matsu, Sakyo-ku, Kyoto 606-8501, Japan
3Ministry of the Environment, No. 5 Godochosha, 1-2-2 Kasumigaseki, Chiyoda-ku, Tokyo 100-8975, Japan
4Aso Volcanological Laboratory, Graduate School of Science, Kyoto University, Choyo, Aso, Kumamoto 869-1404, Japan

(Received October 8, 2004; Revised January 21, 2005; Accepted February 9, 2005)

Abstract: We newly developed a technique of radiation thermometry using a Sony'fs consumer digital camcorder. Our system is not only convenience and cost effective but with a better performance than previous infrared thermometers, particularly in the place like a crater of volcano where is abundant in gas. This is because our system uses the submicron wavelength band, in which radiation is less influenced by absorption of gas than in the thermal infrared wavelength (>3 mm). We carried out observations of red glow at Aso volcano and succeeded in measuring the temperature of about 800°C, which is much more acceptable than previously reported values of 200-400°C. When we measure the temperature of about 300-700°C and 600-900°C in the place where is abundant in gas, using the camcorder with the near-infrared and with the visible wavelength mode is better than the thermal infrared region, respectively.
Key words: Thermometer, submicron wavelength, NightShot, red glow, Aso volcano.


Corresponding author E-mail: saito@bep.vgs.kyoto-u.ac.jp


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