AT ATMOSPHERIC MODEL FOR COMPUTING SOLAR-RADIATION

We have modified the model described by King and Buckius [Solar Energy 22, 297 (1979)] in order to determine daily total irradiation psi*GN on a horizontal surface on the ground, taking into account albedo effects, for sunny or cloudy days. Calculations of radiation integrated throughout the day as a function of sunshine duration on S and of classical parameters: air mass m, thickness of precipitable water W and Angstrom turbidity coefficient beta, were made. These parameters are linked, respectively, to measured atmospheric properties such as pressure, dew temperature and horizontal visibility. Calculations were made for one year (1981) using meteorological data from Dakar-Yoff airport and results are compared with daily irradiation measured, for the same period, at Dakar-Hann (C.E.R.E.R.). A quite good agreement is obtained for most of the days of the year.