Study of the solar radiation over Menia

Measurements were carried out at El-Menia (28.12°N, 30.55°E) in Egypt, which lies in the middle of Egypt, 244 km south of Cairo, for a complete year (1997). Measurements were taken using the Eppley pyranometer to measure the global solar radiation (G) in the range from 280 to 2800 nm, and the Eppley pyrheliometer, which measures the normal incidence solar radiation (I) in the range from 280 to 2800 mn along with four direct spectral bands measured using three cutoff Schott glass filters in the range B1 (280–530 mn), B2 (530–630 nm), B3 (630–695 nm) and B4 (695–2800 nm). The monthly variations for all the parameters and the correlations between the different parameters have been calculated. The diffuse solar radiation and the diffuse fraction for Menia have been calculated using three different methods. Computation of the atmospheric turbidity coefficient for each spectral band was carried out using two methods, the Linke and Angstrom methods. The Linke turbidity factor is between 2.01 and 5.86, while the Angstrom turbidity coefficient is between 0.09 and 0.223. This last result shows that Menia is considered to be a highly polluted region.