  Numerous empirical studies have analyzed International Satellite Cloud
Climatology Project data and reached contradictory conclusions regarding the
influence of solar-modulated galactic cosmic rays on cloud fraction and cloud
properties. The Multiangle Imaging Spectroradiometer (MISR) instrument on the
Terra satellite has been in continuous operation for 13 years and thus provides
an independent (and previously unutilized) cloud data set to investigate
purported solar-cloud links. Furthermore, unlike many previous solar-climate
studies that report cloud fraction MISR measures albedo, which has clearer
climatological relevance. Our long-term analysis of MISR data finds no
statistically significant correlations between cosmic rays and global albedo or
globally averaged cloud height, and no evidence for any regional or lagged
correlations. Moreover, epoch superposition analysis of Forbush decreases
reveals no detectable albedo response to cosmic ray decreases, thereby placing
an upper limit on the possible influence of cosmic ray variations on global
albedo of 0.0029 per 5% decrease. The implications for recent global warming
are discussed.

Atmospheric and Oceanic Physics