Measurements of the erythemally effective (sun-burning) direct solar beam, diffuse skylight, and total global ultraviolet irradiance are converted to daily ultraviolet index measurements.
Students performing the activities presented in this paper using measurements expressed in UVI terms get an understanding of how the true global UVI varies depending on where the solar disk is located in the sky and the amount of diffuse skylight that is available at the measurement location.
In Figure 4, the direct solar beam, diffuse skylight and global total UV components are plotted.