The WRDC, located at the Main Geophysical Observatory in St. Petersburg, Russia, processes solar radiation data currently submitted from more than 500 stations located in 56 countries and operates an archive with more than 1200 stations listed in its catalogue. The WRDC is the central depository of the measured components such as: global, diffuse and direct solar radiation, downward atmospheric radiation, net total and terrestrial surface radiation (upward), spectral radiation components (instantaneous fluxes), and sunshine duration, on hourly, daily or monthly basis.