Abstract

This work presents one year data of global solar radiation flux measured at a humid tropical location in West Africa (Iju, Nigeria; 7.15°N, 5.12°E) for the period 1st January to 31st December, 2008. The collected raw data were analyzed using Origin software and Excel spreadsheet to determine the daily means, daily minima and maxima for the period under consideration. The daily mean for the year was 143.66 ± 11.79 Wm^-2day^-1 while the mean of the daily maximum for the year was 653.42 ± 32.33 Wm^-2day^-1. The daily mean maximum of hourly global solar radiation flux was about 620 Wm^-2 for the dry season and 430 Wm^-2 for the wet season. The fluctuations in the daily averages were prominent during the wet season (April to October). The data set showed a double-peak daily mean average of about 200 Wm^-2day^-1 in March and November and a minimum of about 90 Wm^-2day^-1 in July and August.

Key words: Solar radiation, daily averages, Iju, Nigeria, humid tropical.