A statistical model of solar radiation daily variability

A statistical model to characterize solar radiation taking into account the daily variability is proposed. The model, starting from measured data of solar radiation and historical data referring to its monthly average values, is able to generate synthetic time series. To obtain such scope, it combines information taken from the `clear sky' theoretical model with the random extraction of the determinations of two random variables suitably defined. The results of numerical applications demonstrate the effectiveness of the proposed model.