“…By analysis of the figure, the strength of the procedures shown in Section 5 clearly appears to be predicting the different behavior during the day, not only in terms of radiation level but also in terms of variability of instantaneous solar irradiance. The first part of the day, in fact, is characterized by low values of mean solar irradiance (low r k 1,22,10 , see Equation (16)) and a significant variability value. The second part of the day, instead, is characterized by a regular profile of the solar irradiance with a high value of mean solar irradiance (high r k 2,22,10 , see Equation (16)).…”