Copernicus Atmosphere Monitoring Service (CAMS) includes:

CAMS McClear: A time-series of solar radiation that would be received on a horizontal plane at ground level if the sky were clear.

CAM Radiation: A service provides time series of Global, Direct, and Diffuse Irradiations on horizontal surface, and Direct Irradiation on normal plane (DNI) for the actual weather conditions as well as for clear-sky conditions.