Diffuse solar radiation statistics for Italy

Abstract In this paper diffuse radiation is correlated with usually measured or more easy computable quantities in order to have a larger number of data available for the various applications of solar energy. Here are used two types of correlation: (a) diffuse radiation as a function of global and extraterrestrial radiation; (b) diffuse radiation as a function of ralative sunshine and extraterrestrial radiation. On the basis of the above correlations, empirical equations have been proposed and their coefficients have been calculated by fitting the experimental data of three Italian stations. The degree of accuracy of the fit has been estimated by a coefficient introduced and called by us “r…

An atmospheric model for computing direct and diffuse solar radiation

Abstract This paper proposes an atmospheric model, which extends the computation of the direct radiation given by Cole's model to the cloudy sky and shows a method to calculate the diffuse radiation. Therefore the monthly average values of the global radiation incident on a horizontal surface at Palermo are computed by this method. These values are compared with the experimental data provided by the Istituto di Idraulica Agraria, Universita di Palermo and generally exhibit a mean deviation not more than 10 per cent. The deviations become lower than 8 per cent taking into account the effect of the underlying surface albedo. In order to better verify the validity of the proposed method, it sh…

An atmospheric model applied to some actinometric stations of Sicily

Abstract In this paper the application of an atmospheric model proposed by S. Barbaro et al. in a previous work for computing the direct and diffuse solar radiation is extended to some actinometric stations in Sicily, namely Gela, Messina, Pantelleria, Trapani and Ustica. The comparison of the monthly average values of the global radiation computed by this method with the experimental data shows a good agreement, that confirms the encouraging results obtained for Palermo in the previous work. This further test of the validity of the proposed model allows this one may be used with good reliability to predict the radiation on locations lacking in actinometric instruments. Finally, the influen…

COMMENT ON THE SPACE TRANSLATION METHOD AS USED IN LASER-ASSISTED COLLISION PROBLEMS

Global solar radiation in Italy

Photoionization of hydrogen by a chirped, short X-ray pulse in the presence of a laser field

The ionization of hydrogen by a chirped XUV pulse in the presence of a few cycle infrared laser pulse is investigated. It is found that the combined action of the chirped pulse and the laser eld brings about asymmetries in the photoelectron momentum distribution that may be exploited for obtaining information on both the chirp and XUV pulse duration.

Correlation between relative sunshine and state of the sky

Abstract It is possible to construct a sunshine map referring to a large zone, lacking in a widespread network of recording stations, correlating the relative sunshine with the “state of the sky”, defined by the monthly mean number of the clear, mixed and overcast days, whose data are more largely available. In the correlation here proposed climatological and meteorological factors are introduced in order to express the helioclimatic characteristics of every location. The application to Italy, using the data of the period 1973–1977 provided by the 31 stations of ITAV, has suggested the classification of these stations in seven “helioclimatic groups” characterized by different values of the …