Clear-sky broadband irradiance : first model assessment in Uruguay

Abstract

Three simple clear-sky models using easily available mean average atmospheric data are evaluated against hourly ground data for five sites in Uruguay. The ESRA model, based on a mean daily cycle Linke Turbidity calculated from independent GHI ground data, is the best model. It predicts clear-sky irradiancie with typical uncertainties under 5 % and bias under 1 % of the average GHI for all sites considered. This is low enough for it to be useful in automatic quality check procedures for ground data and also as a basis for all-sky irradiance estimation based on satellite information.