6533b858fe1ef96bd12b574c

RESEARCH PRODUCT

Applicability of a simple model for computing diffuse solar radiation to locations of the European, African, Asian and North American areas

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Abstract It is tested if the correlation type D = K(s/S)−0.25 (sin hn)1.55, 0.2 ⩽ s/S ⩽ 0.9 previously proposed by Coppolino for Italian locations using K = 7.0, allows a reliable estimation of the monthly mean daily diffuse solar radiation D (MJ m−2 day−1), from only the monthly mean daily relative sunshine s/S and the noon altitude of the sun on the 15th of the month hn (degrees) at locations of the European, African, Asian and North American areas. The test is performed at 14 stations in the above areas displaced at various latitudes L, elevations above sea level E and geographical situations, using K = 7.0 for the stations where 0.48 ⩽ (s/S)m, ⩽ 0.63, K = 8.5 for those where 0.40 ⩽ (s/S)m 0.63, and K = 10.0 for those where (s/S)m