Validation of the Accuracy of NASA Solar Irradiation Data for Four African Regions

Abstract

Unfortunately, most developing countries lack meteorological data from weather stations due to a lack of measurement instruments or the absence of these stations. Currently, a variety of spatial databases, such as NASA/Power, Meteonorm, Solargis, and others, provide solar irradiation data for various places and time intervals. The goal of this study is to verify the accuracy of solar irradiation data from the National Aeronautics and Space Administration (NASA) database (free estimated data) by comparing them with ground-based measurements taken at four distinct locations in Algeria and Mauritania. Using six statistical parameters, data downloaded from the NASA site for 34 years, from 1984 to 2017, were averaged and compared to ground-based data recorded at M'Sila, Saida, Tamanrasset, and Nouakchott for one year (365 days) on daily (n = 365), monthly (n = 30 or 31), and annual (n = 12) time scales. It has been found that in the absence of daily measured global horizontal irradiation data for one year, the estimated multi-year average NASA data can be used instead. The use of estimated data over a long period is recommended. In the absence of actual solar irradiation data, solar energy projects in Algeria and Mauritania can rely on NASA's estimates.