Af. Bais et al., CORRECTING GLOBAL SOLAR ULTRAVIOLET-SPECTRA RECORDED BY A BREWER SPECTRORADIOMETER FOR ITS ANGULAR RESPONSE ERROR, Applied optics, 37(27), 1998, pp. 6339-6344
We present a methodology for correcting the global UV spectral measure
ments of a Brewer MKIII spectroradiometer for the error introduced by
the deviation of the angular response of the instrument from the ideal
response. This methodology is applicable also to other Brewer spectro
radiometers that are currently in operation. The various stages of the
methodology are described in detail, together with the uncertainties
involved in each stage. Finally global spectral UV measurements with a
nd without the application of the correction are compared with colloca
ted measurements of another spectroradiometer and with model calculati
ons, demonstrating the efficiency of the method. Depending on waveleng
th and on the aerosol loading, the cosine correction factors range fro
m 2% to 7%. The uncertainties involved in the calculation of these cor
rection factors were found to be relatively small, ranging from simila
r to 0.2% to similar to 2%. (C) 1998 Optical Society of America.