Atmospheric Assessment & Evaluation

Cloud Formation and Character

In the Clouds

The transformation of invisible atmospheric water vapor to visible water droplets and ice crystals is governed by nucleation. The character of the local aerosols governs how quickly nucleation occurs, whether it is the formation of cloud (by cloud condensation nuclei, CCN) or the development of ice within a water cloud by ice-forming nuclei, IN).

The most common forms of nuclei:

(wind-borne dust)
(sea spray)
(ash, dust)
(combustion of fossil fuels, dust)
(smoke and ash)
General pollution
(from industry)

These aerosols provide the various nuclei that govern cloud and precipitation development.

Knowledge of cloud character is essential to understanding natural precipitation.

The effects of human-made aerosols on natural precipitation and the potential for certain other human-made aerosols (cloud seeding) to favorably influence cloud processes.

Aerosol measurements reveals information critical to cloud and precipitation processes, including the quantification of cloud condensation nuclei, and ice nuclei.

For the measurement of aerosols that function specifically as nuclei that affect cloud and precipitation processes, Weather Modification, Inc., recommends:

  • Cloud Condensation Nuclei Counter
  • Acoustic Ice Nucleus Counter (AINC)