Intercomparison of spectroradiometers for solar spectral irradiance measurements preliminary results

This paper describes the preliminary results of an intercomparison of spectroradiometers for direct (DNI) and global normal incidence (GNI) irradiance in the visible (VIS) and near infrared (NIR) region. Seven institutions and six spectroradiometers, representing different technologies and manufacturers were involved. All instruments were able to measure GNI; a restricted sub-group of four instruments had the possibility to also measure DNI when equipped with proper collimators. Prior to the intercomparison, all participating institutions calibrated their own instrument(s) according to their usual procedures in order to verify the entire calibration and traceability chain.