A methodology for the absolute calibration of spectral measurements of direct solar ultraviolet radiation, performed with a Brewer spectrophotometer is presented. The method uses absolute measurements of global and diffuse solar irradiance obtained practically simultaneously at each wavelength with the direct-Sun component. On the basis of this calibration, direct-Sun spectra, measured over a wide range of solar zenith angles at a high altitude site, were used to determine the extraterrestrial solar spectrum by applying the Langley extrapolation method. Finally this spectrum is compared with a solar spectrum derived from the airborne tunable laser absorption spectrometer 3 Space Shuttle mission, showing an agreement of better than ±3%.
© 1997 Optical Society of America
Original Manuscript: December 19, 1995
Revised Manuscript: November 7, 1996
Published: July 20, 1997
Alkiviadis F. Bais, "Absolute spectral measurements of direct solar ultraviolet irradiance with a Brewer spectrophotometer," Appl. Opt. 36, 5199-5204 (1997)