Comparison between Measurement and Model

Ratio of measured and modelled UV irradiance: (top) UVA (315-400 nm); (middle) erythemal irradiance; (bottom) spectral irradiance, averaged over five different solar zenith angle intervals. Each data point in the upper two plots corresponds to a measured spectrum. The figure, which has recently been published in [WMO, 1998] shows an updated version of the data presented in the thesis and in [Mayer et al., 1997]: the measurements have been post-corrected for radiometric accuracy and stability, and a small non-linearity of the instrument; an improved algorithm has been used to correct the cosine error of the instrument. For more details about model and measurements as well as the methods of the comparison please refer to [Mayer et al., 1997]