On the relation between rain, clouds, and cosmic rays.

We investigate the correlation between precipitation, clouds and cosmic rays based on field observations to develop a new short-term forecasting tool for their extremely high values. The results show that the cosmic ray intensity appears to be highly correlated with the one-year time-lagged rainfall amount with the cosmic rays leading. A plausible explanation is given for this, based on the modulation of cosmic rays by the solar cycle and an earlier finding of a strong correlation between the stratospheric - lower mesospheric temperature fluctuations and the sunspot number cycle with a time lag of one year (sun leading). This suggests that cosmic rays are not the trigger, but rather signals sunspot activity that with a delay of one year may affect cloud formation and therefore rainfall. In addition, high rates of rainfall exhibit a power-law behavior, such as the Gutenberg-Richter law characterizing the large area and perimeter size of rainfall and clouds, which have been proposed recently. Finally, the new tool for the nowcasting the extremely high cosmic ray intensity values can be used for nowcasting the extremely high rainfall values. Their combination can be used to study the modulation of cosmic ray properties by climate change parameters. [ABSTRACT FROM AUTHOR]