A Possible Indirect Mechanism Linking Solar activity and Climate

Abstract

Solar variability is one of the main natural influences on the Earth's climate. Biological processes are profoundly affected by the solar irradiance. Some of these processes have been proposed to change the cloud albedo and therefore impact the climate. In this work we investigate the relation between the total solar irradiance (TSI) and the global concentration of Dimethylsulphide (DMS), produced by plancktonic algae in seawater. DMS has been frequently mentioned as a forcing of climate through its effect on clouds and therefore on albedo. We found that the TSI and the DMS production data series display a non linear correlation. Then a probabilistic scheme is introduced, the Mutual Information Function which is a measure of the dependence between the parameters of interest. The Mutual Information Function seems to present a solar cycle dependence: larger values during lower solar activity times (lower TSI times) than during higher solar activity epochs (higher TSI epochs). Or in other words, the dependence between TSI and DMS is stronger during lower solar activity times than during higher solar activity epochs.