Low cloud properties influenced by cosmic rays

The influence of solar variability on climate is currently uncertain. Recen t observations have indicated a possible mechanism via the influence of sol ar modulated cosmic rays on global cloud cover. Surprisingly the influence of solar variability is strongest in low clouds (less than or equal to3 km) , which points to a microphysical mechanism involving aerosol formation tha t is enhanced by ionization due to cosmic rays. If confirmed it suggests th at the average state of the heliosphere is important for climate on Earth.