Total Irradiance Measurements of ACRIM I and ACRIM II

This chart shows the ACRIM I and ACRIM II data. ACRIM I flew on the Solar Maximum Mission spacecraft from 1980 to December 1989. ACRIM II was launched September 1991 and is still operating. The data shows the daily average of the total solar irradiance at 1 AU (the distance from the center of the sun to the center of the earth). The data shows that at solar maximum the energy output from the sun is highly variable compared to the quiet of solar minimum.