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Two agencies in Japan monitor UV radiation: The Japan Meteorological Agency operates five Brewers and the National Institute for Environmental Studies operates one Brewer. The five Brewers operated by JMA are Mark II measuring between 290 and 325 nm every .5 nm. Dr. Tomoyuki Ito is in charge of this network. They have four of the Brewers in Japan and the fifth in Antartica. The four brewers in Japan cover a broad latitudinal gradient. The one instrument operated by NIES was in Tsukuba until November of 1993, when it was moved to Tokyo to monitor in a high population area. Dr. Naoki Furuta is in charge of data quality for this monitoring. Nobuo Munakata at the Japanese National Cancer Center Research Institute has been measuring UV by spore dosimetry since 1980.
For monitoring harmful solar ultraviolet radiation reaching the Earth's surf ace, JMA started to observe solar spectral irradiance at Tsukuba (36.1 N) since January of 1990, and at Sapporo (43.1 N), Kagoshima (31.6 N), and Naha (26.2 N) since January 1, 1991. This monitoring is performed by ground-based Brewer spectrometers (MK II, SCI-TEC, Canada).
Spectral UV irradiance is observed within 5 minutes of every hour from 30 minutes before sunrise to 30 minutes after sunset. Spectral UV irradiance is measured by scanning at every 0.5 nm wavelength between 290 nm and 325 nm. One observation takes about 8 minutes. Instrument calibrations are made by using internal, external, and NIST lamps.
Spectral UV irradiance data is submitted to the WOUDC in Toronto every two months. The data is also printed in the Annual Report on Monitoring of the Ozone Layer of JMA, including ozone data observed at the above mentioned four stations. Analytical results of these data are summarized in the Annual Report of the Ozone Layer Monitoring in Japan.
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