The total solar radiation during the harmattan months of 1982 to the early part of 1984 at Enugu, Nigeria, which lies on latitude 6.47°N and longitude 7.55°E and 140 m above sea level, has been measured and analysed. The effect of the dust haze prevalent at this time is evaluated. Results reveal that the effect of the harmattan is high during the months of November and January but is highest in December. The fairly high dust haze during this period gave a sky condition similar to overcast weather with a clearness index, KT, of 0.36.The use of Page’s relation for prediction of the diffuse component of radiation is recommended. The regression coefficients a and b in the Angstrom equation are obtained. The predicted solar radiation, using the above relationship, compares well with measured values with an error of 0.07.These predicted patterns are suggested for use in areas of similar climatological variables and will serve well in evaluating the performance of any solar device during the harmattan period.
Energy Conversion and Management 01/1985; 25(4):487-490. DOI:10.1016/0196-8904(85)90014-7