http://arxiv.org/pdf/0803.2298.pdfIn conclusion, no corroboration of the claim of a causal connection between the changes
in ionization and cloud cover, made in [1, 2], could be found in this investigation.
From the
distribution of the depth of the dip in solar cycle 22 with geomagnetic latitude (the VRCO)
we find that, averaged over the whole Earth, less than 23% of the dip comes from the solar
modulation of the cosmic ray intensity, at the 95% confidence level.
This implies that, if the dip represents a real correlation, more than 77% of it is caused by a source other than ionization and this source must be correlated with solar activity.http://atmos-chem-phys.net/8/7373/2008/ ... 3-2008.pdfThe overall conclusion, built on a series of independent
statistical tests, is that no clear cosmic ray signal associated
with Forbush decrease events is found in highly susceptible
marine low clouds over the southern hemisphere oceans.Whether such a signal exists at all can not be ruled out on the
basis of the present study, due to the small number of cases
and because the strongest Forbush decrease events indicate
slightly higher correlations than the average events. Even
though those strong events are rare, with only 6 events over
5 years, the amplitude is similar to that occurring during the
solar cycle, so from a climate perspective these strong events
may deserve particular attention. Further investigations of
a larger number of such events are needed before final conclusions
can be drawn on the possible role of galactic cosmic
rays for clouds and climate
http://www.atmos-chem-phys.net/10/1885/ ... -2010.htmlHere, we report unique observations on atmospheric aerosol formation based on measurements at the SMEAR II station, Finland, over a solar cycle (years 1996–2008) that shed new light on these presumed relationships. Our analysis shows that none of the quantities related to aerosol formation correlates with the cosmic ray-induced ionisation intensity (CRII). We also examined the contribution of ions to new particle formation on the basis of novel ground-based and airborne observations.
A consistent result is that ion-induced formation contributes typically significantly less than 10% to the number of new particles, which would explain the missing correlation between CRII and aerosol formation. Our main conclusion is that galactic cosmic rays appear to play a minor role for atmospheric aerosol formation events, and so for the connected aerosol-climate effects as well.