Comparison between the measured (in black) and the fitted (in colour) irradiances, for four wavelengths on the left and their residual on the right. The measurement precision (4% for SEE, 1% for SOLSTICE) is indicated in each plot. The fit is based on the set of passbands described in the text. The model parameters are estimated from the maximum and the minimum of the solar cycle (in red), while the relative error is estimated within the blue interval, which corresponds approximatively to 1600 days.