cloud condensation nucleus
Sign in to saveAlso known as CCN, cloud seed, condensation nucleus, cloud condensation nuclei, condensation nuclei, cloud seeds
small particle (typically 0.2 µm) on which water vapor condenses
~9 min read
Encyclopedic overview
Aerosol pollution over northern India and Bangladesh (Satellite image by NASA)
Cloud condensation nuclei (CCNs), also known as cloud seeds, are small particles typically 0.2 μm, or one hundredth the size of a cloud droplet. CCNs are a unique subset of aerosols in the atmosphere on which water vapour condenses. This can affect the radiative properties of clouds and the overall atmosphere. Water vapour requires a non-gaseous surface to make the transition to a liquid; this process is called condensation.
Excerpted from Wikipedia’s “cloud condensation nucleus” article, available under the CC BY-SA 4.0 licence.