The Smithsonian solar constant data revisited: no evidence for cosmic-ray induced aerosol formation in terrestrial insolation data

Abstract

Apparent evidence for a strong signature of solar activity in terrestrial insolation data was recently reported. In particular, a surprisingly strong increase of terrestrial insolation with sunspot number as well as a decline of the brightness of the solar aureole and the measured precipitable water content of the atmosphere with solar activity was presented. The latter effect was interpreted as evidence for cosmic-ray induced aerosol formation. Here I show that these spurious result are due to a~failure to correct for seasonal variations and the effects of volcanic eruptions and local pollution in the data. After correcting for these biases, the atmospheric water content, the solar aureole brightness, and the terrestrial insolation show no significant trend with solar activity. Hence there is no evidence for the influence of solar activity on the climate being stronger than currently thought, or a cosmic-ray mechanism linking the two.