FUZZY ALGORITHM FOR ESTIMATION OF SOLAR IRRADIATION FROM SUNSHINE DURATION

Solar irradiation and sunshine duration are intimately related phenome na and a model involving the relationship between them can best be der ived by methods that explicitly take vagueness into account. In this p aper, the theory of fuzzy sets, especially fuzzy modeling, is employed to represent solar irradiation and sunshine duration relations as a s et of fuzzy rules. A fuzzy logic algorithm has been devised for estima ting the solar irradiation from sunshine duration measurements. The ma in advantage of fuzzy models is their ability to describe the knowledg e in a descriptive human-like manner in the form of simple rules using linguistic variables only. In this manner the classical Angstrom or a ny other type of regression equations can be replaced by a set of fuzz y rule bases. The fuzzy approach is applied for three sites with month ly averages of daily irradiances in the western part of Turkey. (C) 19 98 Elsevier Science Ltd. All rights reserved.