What is a Cloud?
Fluffy and buoyant, wispy and moody, clouds arise in billions of different forms, each one unique in their characteristics and presence. Though, as beautiful and charismatic as each one is, what exactly is a cloud, and how do they come to be?
At its most basic definition, a cloud is a mass collection of water droplets that form from the cooling of water vapor in the atmosphere. Depending on the altitude in the atmosphere, these water droplets cool either into water droplets or ice crystals. The higher in the atmosphere these droplets cool, the more likely they are to form ice crystals. These millions of tiny ice crystals then come together to form various sorts of cirrus clouds, thousands of feet in the air.
Though, there is plenty of water vapor in the atmosphere just drifting about, so why is it that only some of this comes together to form a cloud? The answer to this question is CCN, or Cloud Condensation Nuclei. These miniscule particles in the atmosphere, on average only about 2 micrometers in diameter, are the surfaces on which water vapor may condense and become liquid. CCN can be a variety of particles, such as dust, salt, or other atmospheric aerosols. When water vapor collides with these particles, it condenses to form cloud droplets. These cloud droplets then accumulate to form what we know as clouds, be they composed of ice or liquid droplets.
From cumulus, to stratus, cirrus and even the most abstract and rare forms of clouds, all undergo some form of this general process. Despite variations in some of the processes for different cloud types, all come to be those beautiful, powerful, and lovely formations that dot our skies.
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© 2020 Weather Forecaster Alexis Clouser