How Do Clouds Form?

  • Thread starter Thread starter Kalrag
  • Start date Start date
  • Tags Tags
    Form
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
2 replies · 6K views
Kalrag
Messages
104
Reaction score
0
I have been confused by a what seems to be a simple process. Can anyone post a step-by-step process of how clouds come to be?
 
Earth sciences news on Phys.org
Kalrag said:
I have been confused by a what seems to be a simple process. Can anyone post a step-by-step process of how clouds come to be?

Why do clouds coalesce water vapor rather than diffuse it, in light of the fact that small condensing vapor molecules are generally negatively charged? Shouldn't the electrical repulsion between the droplets prevent them from forming clouds at all?

What is being observed in laboratory experiments is that the surface of water, including surface tension, but also situations like water vapor condensing around nuclei of condensation in the atmosphere (which nuclei are also negatively charged), creates a layer of positive charge around it - the "exclusion zone" or EZ. When two or more droplets are in the vicinity of each other, this positive charged EZ is increased in the zone just between the particles, creating a region of neg/pos/neg in which the neg charges actually attract toward each other. As Feynman said, "Like likes like."

Respectfully submitted,
Dotini
 
Kalrag said:
I have been confused by a what seems to be a simple process. Can anyone post a step-by-step process of how clouds come to be?

It is not at all a simple process. Although vaporization is spontaneous, condensation is not. It usually requires the right conditions and the presence of cloud condensation nuclei. Even then, it doesn't always occur as you might expect. A good introduction to the subject is:

R. R. Rogers and M. K. Yau, A Short Course in Cloud Physics; Third Edition, 1989; Elsevier Science Library, Burlington, MA.