Reconstruction of long-term direct solar irradiance data series using a model based on the Cloud Modification Factor

摘要: This paper develops a semi-empirical model to calculate direct solar shortwave irradiance on horizontal surface for any cloudiness condition. The is based radiative transfer simulations combined with empirical relationships; it makes use of the global irradiance, experimentally measured in most radiometric stations, and Cloud Modification Factor (CMF). A dataset from eight Spanish locations used tune parameters part data validate model. By using long-term series experimental data, corresponding irradiances are reconstructed each location proposed An evaluation performance carried out different zenith angles. Following, monthly averages hourly were calculated values. high correlation found when compared To make obtained results, characterization typical climatic values Spain out. results provide representative radiation show availability this resource studied areas.