Performance Evaluation of CAMS Reanalysis for Improved Solar Resource Assessment and Forecasting in Qatar’s Desert Climate

Solar resource assessment is essential for the planning and operation of solar energy projects, with ground-based measurements providing the most accurate data. In their absence, satellite-derived solar radiation products offer a valuable alternative due to their broad spatial and temporal coverage, though their accuracy must be carefully evaluated for reliable application. This study assesses the performance of the CAMS Radiation Service (CRS), a satellite-based solar radiation dataset from the European Union’s Earth observation program, under the hot desert climate of Qatar. Historical CRS data—Global Horizontal Irradiance (GHI), Direct Normal Irradiance (DNI), and Diffuse Horizontal Irradiance (DHI)—were compared against ground-based measurements from QEERI’s solar monitoring station in Doha, recorded at 1-minute resolution over a 38-month period. The evaluation employed statistical indicators including Pearson’s correlation coefficient (Cf), relative root mean square error (rRMSE), and relative mean bias error (rMBE). Results show that CRS reproduces GHI with the highest accuracy, exhibiting the lowest rRMSE and rMBE, while DNI and DHI demonstrate significantly larger biases and errors. Furthermore, periodic monthly variations in rRMSE were observed across all components. These findings suggest that CRS-derived GHI can serve as a reliable substitute when ground measurements are unavailable, though greater caution is required when using DNI and DHI.