Estimation of global solar radiation in selected synoptic stations in Ghana

Abstract

The global solar radiation potential of eight Synoptic Meteorological Stations in Ghana was reported in this study. Five stations were selected from the Northern belt, mostly made up of Sudan Savanna and Guinea Savanna regions of Ghana and the other three stations were selected from the Middle belt, mainly Deciduous Forest and Coastal Savanna regions of Ghana. Angstrom-Prescott Sunshine Hour Model was employed to estimate the global solar radiation for these stations. The daily sunshine hour data and other geographical parameters were obtained from the Ghana Meteorological Agency in Accra for the period of 2000 to 2010. Monthly and yearly means of daily global solar radiation values were determined for each of the selected Synoptic Stations.The computation and the analysis were done using MatLab codes together with Microsoft excel. Standard error was determined to check the consistency of the global solar radiation values obtained. Also, the performance of the model was evaluated by using a standardized test statistics (z-statistics).The yearly mean of monthly global solar radiation values for the entire period for the Selected Synoptic Stations ranged from 19.94 MJm-2day-1 to 21.95 MJm-2day-1 using Angstrom– Prescott Sunshine Hour model. In general, maximum values of yearly mean of monthly global solar radiation for the Study Synoptic Stations were observed between March and April, while minimum values were observed in August and December. From analysis of the result, it was observed that the availability of global solar radiation throughout the period in the selected stations is very consistent and steady in pattern. Therefore, the possibility of prospects of solar energy utilisation at these locations is very bright.