Clouds
Classification, Nimbus Category, High Clouds, Middle Level Clouds, Low Level Clouds, Unusual CloudsCloud categories
All clouds are a form of water. Clouds are condensed atmospheric moisture in the form of minute water droplets or ice crystals. The creation of a cloud begins at ground level. The sun heats the earth's surface, the warm ground heats the air, which rises. The air contains variable amounts of water, as vapor, that has evaporated from bodies of water and plants. Air at ground level is denser than air higher up, and as the warm air rises, it expands and becomes less dense. Expansion cools the air and as the air cools, the water vapor that is present in the air, condenses into tiny microscopic droplets. Cloud formation depends on how much water is in the atmosphere,
Cirrus clouds (top) and cumulus clouds (bottom).
Today, there are 10 characteristic forms or genera of clouds recognized by the International Cloud Classification, and there are three height categories with an established altitude range for each category. Low-level clouds range from the surface to 6,500 ft (2,000 m), mid-level from 6,500-23,000 ft (2,000-7,000 m), and high-level, generally above 20,000 ft (6,000 m). Below is a brief description of each category and their genera.
Additional topics
- Club Mosses
- Clouds - Classification
- Clouds - Nimbus Category
- Clouds - High Clouds
- Clouds - Middle Level Clouds
- Clouds - Low Level Clouds
- Clouds - Unusual Clouds
- Other Free Encyclopedias
Science EncyclopediaScience & Philosophy: Chimaeras to Cluster