Uncertainty of experimental integrals: Application to the UV index calculation

A procedure is presented to evaluate the uncertainty of integrals computed from an approximate function that interpolates a set of measured data. The procedure, a Monte Carlo-based uncertainty propagation technique, yields the integral uncertainty taking into account the uncertainties associated with the involved experimental data. As expected, we found that the uncertainty of the integral strongly depends on the error sources affecting the ordinates. As an example, we assessed the uncertainty of the so-called UV index, evaluated by integrating in the range 250 nm to 400 nm the biologically weighted spectral ultraviolet irradiance. The presented procedure agrees with international recommendations and is valid independently of the experimental technique from which data are obtained.