Expert Quality Control of Solar Radiation Ground Data Sets
Abstract
Ground-based radiation measurements are required for all large solar projects and for evaluating the accuracy of solar radiation models and datasets. Ground data almost always contain low-quality periods caused by in-strumental or logging errors. Therefore, quality control (QC) is needed to exclude such suspicious or erroneous data, before any subsequent analysis. The various existing automatic QC methods are not perfect, thus expert visual inspection of the data is still required. In this work, we present a harmonized QC procedure, which is a combination of various available methods from the literature that includes an expert visual inspection. In the framework of IEA PVPS Task 16, these tests are applied to 161 stations, which are candidates for the bench-mark of irradiance datasets derived from satellite or weather models. As the expert decisions might lead to different QC results, the independently obtained results from nine evaluators are compared for two sites. The QC results are similar, but some deviations are found due to different manual flagging and the implementation. Keywords: solar irradiance, quality control, quality inspection, visual inspection.