Spectral distribution of global and diffuse solar radiation in Ny-Ålesund, Spitsbergen

Abstract

Spectral distributions of solar radiation were measured over the wavelength range 300 to 800 nm in Ny-Ålesund (78°55′N, 1 I°56′E). The apparatus consisted of a grating monochromator with an automatic scanning system, an integrating sphere supposed to give a good picture of the radiation received on a horizontal surface from the whole celestial hemisphere, a photomultiplier tube with S-20 response, and a strip chart recorder. Great importance was attached to the calibration procedure, which was carried out by means of a 1000 W quartz-iodine lamp with known spectral irradiance (calibration traceable to NBS, delivered by Eppley Laboratory). The main part of the discussion is based on relative spectral distributions. Spectra in absolute units were obtained by comparison with simultaneous pyranometer recordings of total solar energy, which by means of filter measurements could be reduced to the same wavelength range as for the spectral scans. In addition, the pyranometer recordings served as a means of judging...