Theory Observation |
Clouds
IN SHORT - Apart from being a fine view, clouds are the the manifestation of the water cycle at Earth, with moist rising from the continents and seas, as the clouds are a major player too in our planet's energy |
budget, with their top reflecting the solar radiation, and their bottom trapping the re-radiated heat from the surface. This page provides too a view of the clouds categorization |
Clouds are the main visible elements of the weather which is taking place in the troposphere. Clouds are ensembles of microscopic water droplets or icy crystals. Clouds are an important step in the water cycle at Earth as they are the result of the condensating moisture coming from soil and as they are eventually turning water into precipitations falling back Earth. On the other hand clouds are an important actor of the Earth's energy budget as clouds top is reflecting the solar radiation while clouds base is trapping re-radiated heat from the surface. Thus clouds are an element of the natural greenhouse effect
Clouds are sorted into four main categories depending on the altitude of their base. Various main types are sub-dividing the categories. More than 100 types of clouds exist
Altitude Clouds
Altitude clouds are composed of icy crystals and found above 20,000 ft (6 km)
- cirrus are white threadlike thin clouds arranged in bands
- cirrostratus are whitish veil covering a huge area of sky (they are responsible for moon halo)
- cirrocumulus are small fleecy balls and threads, arranged in groups usually covering just a small section of sky
Middle Altitude Clouds
Middle altitude clouds are composed of water droplets or of icy particles if temperature is appropriate. They are found between 2 and 4 miles (3-6 km)
- altostratus are gray or bluish veils as the Sun is seen only diffusely. They tend to cover the whole sky
- altocumulus are fleecy large balls or puffs
Low Clouds
Low clouds are composed of water droplets but they may turn into icy crystals or snow temperature permitting. They are found under 1 mile of altitude (1.6 km)
- stratocumulus are large gray rolls of clouds frequently covering the whole sky
- nimbostratus are dark and shapeless, covering large areas of sky. They are the typical precipitation clouds, yielding rain and snow
- stratus are at less than 2,000 ft (610 m) and are sheets of white blankets covering moslty the whole sky. They may linger for several days and they yield precipitation when turning into nimbostratus. The sky is usually clear and blue beyond. Such sheet clouds are forming in calm air.
Multi-Level Clouds
Multi-level clouds are ranging in altitude from less than 1 mile to more than 8 miles (1.6-13 km)
- cumulus are the typical white and woolpack clouds of sunny weather. They usually appear starting at midday as solar heat has produced then the rising air currents necessary to produce them
- cumulonimbus are these dark, high-rising, massive clouds which are responsible for thunderstorms, lightnings, and hail. Such towering clouds are forming in windy air or air with strong vertical currents. Cumulus may develop into cumulonimbus
Clouds types present at a given location depend on the weather fronts existing there
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