Brewer Spectrophotometer Calibration and Observation Data

Calibration and observation results

Maintenance and management

Appropriate maintenance and management of Brewer spectrophotometers are essential because they are very precise optical instruments. In Japan they are overhauled every three years.

Calibration method

Definition of instrument constants for Brewer spectrophotometers in Japan is based on the irradiance of 1,000-W NIST standard lamps. Calibration is performed via intercomparison with the JMA standard (BR#174) and the traveling standard (BR#113) using solar radiation every three years in conjunction with overhauls.

Brewer Spectrophotometer intercomparison

The JMA standard instrument is calibrated via intercomparison with the world standard Brewer spectrophotometers at Environment Canada in Toronto, Canada, every three or four years.

Observation data

Quality-checked data are published in JMA's Annual Report on Atmospheric and Marine Environment Monitoring Data as well as on the World Ozone and Ultraviolet Data Centre (WOUDC) website.

Diurnal variation of UV Index

Seasonal variation of UV Index (2017)

Annual variation of UVB irradiance