A statistical analysis of the solar daily global irradiation for Genoa, Italy, has been carried out using a 9 year time series. The frequency distribution of the fluctuations in the daily values of the time series about the mean, normalized by the standard deviation, has been transformed into a standard Normal distribution. An Autoregressive process of order 1 has been fitted to the transformed series. The daily means and the standard deviations have been estimated by two approaches, viz. (i) Fourier expansion of the daily means and standard deviations with one and two harmonics, respectively; (ii) smoothing of the daily values of these parameters by the “monthly averages method”. For both the approaches, the Autoregressive parameter has been estimated in two ways, viz. (i) keeping it time invariant; (ii) changing it day by day during a year. The fitted model has been used to generate synthetic sequences of daily solar irradiations. All the four methods produce synthetic series which almost satisfactorily match the empirical one without showing any appreciable superiority of the one over the other method.
