Spectral Solar Radiation Characteristics Under Desert Conditions

Ground-level solar spectral measurements, which are scarce in general, are important to assess the performance of photovoltaic (PV) technologies. Indeed, PV materials have different responses with regards to the spectral distribution of solar radiation. In order to study the impact of solar spectral variations on PV, the terrestrial solar spectrum needs to be characterized and quantified. In this work, we present the analysis of solar spectral irradiance measurements recorded for a period of one year, in desertic atmospheric conditions. The spectral measurements are done on a tilted surface at an angle equal to the latitude of the studied location, and wavelength range from 350 nm to 1050 nm. The analysis covers several temporal resolutions. Moreover, the local spectral variations are characterized in terms of the variations in the average photon energy (APE) parameter as well as the useful fraction (UF) parameter specific to different PV technologies.