Evaluation of solar radiation and luminosity in Chile. I. Formula calibration to estimate daily global solar radiation

Haydée Castillo G. 1 y Fernando Santibañez Q.1

Varios emprirical equations (Angstrom type) were tested as estimators of global solar radiation in 18 chilean localities. Local equations, including correction coefficients, are propesed, since none of them is homogeneus enough to be used through all the regions. Direct regressions between relative insolation (n/N) and attenuations of solar radiation (incident global radiation/extraterrestrial radiation) produce equations which can no be generalized to the whole country. Equations obtained by local calibration, starding from a unique formula, Rge = Ra (0.25 + 0,50 n/N), allow estimations with errors smaller than 18 cal cm-2 day-1, for an average of 382 cal cm-2 day-1 for the localities tested.

1Prof. de Biol. e Ing. Agr., Dr., respectivamente, Facultad de Agronomía, U. de Chile, Casilla 1004, Santiago, Chile.