Cosmic rays, aerosols, clouds, and climate: Recent findings from the CLOUD experiment

• Published in: Journal of geophysical research. Atmospheres Vol. 122; no. 15; pp. 8051 - 8055
• Main Author: Pierce, J. R.
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 16-08-2017
• Subjects: Aerosol effects on climate; Aerosol nucleation; Aerosols; Climate; Climate effects; Cloud condensation nuclei; Cloud droplets; Clouds; Condensation; Condensation nuclei; Cosmic radiation; Cosmic rays; Droplets; Experiments; Galactic cosmic rays; Geophysics; Growth; Human influences; Nucleation; Yields
• ISSN: 2169-897X; 2169-8996
• DOI: 10.1002/2017JD027475

The Cosmics Leaving OUtdoor Droplets (CLOUD) experiment was created to systematically test the link between galactic cosmic rays (GCR) and climate, specifically, the connection of ions from GCR to aerosol nucleation and cloud condensation nuclei (CCN), the particles on which cloud droplets form. The CLOUD experiment subsequently unlocked many of the mysteries of nucleation and growth in our atmosphere, and it has improved our understanding of human influences on climate. Their most recent publication (Gordon et al. 2017, https://doi.org/10.1002/2017JD026844) provides their first estimate of the GCR‐CCN connection, and they show that CCN respond too weakly to changes in GCR to yield a significant influence on clouds and climate.
Key Points
The CLOUD experiment was designed to probe connections between galactic cosmic rays, aerosols, and clouds
The experiment has led to significant advances in our understanding of aerosol nucleation and growth, and aerosol effects on climate
CLOUD recently found that the impact of decadal fluctuations of galactic cosmic rays on aerosols would have a limited impact on clouds