Estimation of Hourly and Daily Clearness Indices and Diffuse Fraction, over Port Harcourt and Kano using National Centre for Environmental Prediction and National Centre for Atmospheric Research Satellite Data

Estimation of clearness index (KT) and diffuse fraction (KD) were calculated using satellite data obtained from National Centre for Environmental Prediction and National Centre for Atmospheric Research data base covering a period of 10 Years (2005 - 2014) for Port Harcourt and Kano stations which are Coaster and Sahel regions respectively. Direct solar data and diffuse solar data collected were added to give the Global solar radiation. The computed clearness index values were used to characterize the sky conditions into clear skies and overcast skies. Port-Harcourt with low clearness index indicated low global solar radiation while Kano with large clearness index indicated high global solar radiation. The implications of these results on the effective utilization of solar energy are discussed. The results also serve as very useful for solar energy collectors in designing and estimation of solar application systems