Global validation of REST2 incorporated into an operational DNI and GHI irradiance model

Two categories of models can be used to predict direct normal irradiance (DNI) for solar concentration or tracking photovoltaic applications. The first type are broadband radiative models that predict DNI under clear skies from atmospheric data. The second are methods used to extract DNI from global horizontal irradiance (GHI). While many validation studies have been done on the latter the former have only been evaluated in localized studies of a dozen or fewer sites and those mostly in the USA [1,2]. We propose to do a global validation of the REST2 direct irradiance model at 100+ locations world wide against both GHI and DNI.