Investigation of solar spectral irradiance measurements using the spectral matching ratio

The spectral matching ratio (SMR) is an index used to classify the direct solar spectrum based on the relative difference between the spectrum under study and the reference AM1.5 spectrum. This paper evaluates the spectral conditions of a location characterized by a hot semi-arid climate (i.e. BSh by Köppen and Geiger climate classification) using a dataset of several months and the SMR index as a criterion. This is essential to draw conclusions about the spectrum distribution and hence, the applicability of specific photovoltaic (PV) technologies in the particular location. The main atmospheric parameters influencing the solar spectrum were simultaneously registered and an investigation of the SMR as a function of airmass at different aerosol optical depth and precipitable water levels is also performed.