Correlation of spectral solar irradiance with solar activity as measured by VIRGO

Context. The variability of solar spectral irradiance (SSI) over the rotational period and its trend over the solar activity cycle are important for understanding the Sun–Earth connection as well as for observational constraints for solar models. Recently the Spectral Irradiance Monitor (SIM) experiment on the Solar Radiation and Climate Experiment (SORCE) has published an unexpected negative correlation with total solar irradiance (TSI) of the visible spectral range. It is compensated by a strong and positive variability of the near UV range.