Long-Term Solar Irradiance Variability

Measurements of the solar energy throughout the solar spectrum and understanding its variability provide important information about the physical processes and structural changes in the solar interior and in the solar atmosphere...The aim of this paper is to discuss the solar-cycle-related long-term changes in solar total and UV irradiances. The spaceborne irradiance observations are compared to ground-based indices of solar magnetic activity, such as the Photometric Sunspot Index, full disk magnetic flux, and the Mt. Wilson Magnetic Plage Strength Index.