GORGEOUS CLOUDS

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A cloud is a visible mass of droplets or frozen crystals floating in the atmosphere above the surface of the Earth or another planetary body. A cloud is also a visible mass attracted by gravity (clouds can also occur as masses of material in interstellar space, where they are called interstellar clouds and nebulae.) The branch of meteorology in which clouds are studied is nephology.

On Earth the condensing substance is typically water vapor, which forms small droplets or ice crystals, typically 0.01 mm in diameter. When surrounded by billions of other droplets or crystals they become visible as clouds. Dense deep clouds exhibit a high reflectance (70% to 95%) throughout the visible range of wavelengths: they thus appear white, at least from the top. Cloud droplets tend to scatter light efficiently, so that the intensity of the solar radiation decreases with depth into the gases, hence the gray or even sometimes dark appearance of the clouds at their base.
Thin clouds may appear to have acquired the color of their environment or background, and clouds illuminated by non-white light, such as during sunrise or sunset, may be colored accordingly. In the near-infrared range, clouds would appear darker because the water that constitutes the cloud droplets strongly absorbs solar radiation at those wavelengths.


Clouds are divided into two general categories: layered and convective. These are named stratus clouds (or stratiform, the Latin stratus means "layer") and cumulus clouds (or cumuliform; cumulus means "piled up"). These two cloud types are divided into four more groups that distinguish the cloud's altitude. Clouds are classified by the cloud base height, not the cloud top. This system was proposed by Luke Howard in 1802 in a presentation to the Askesian Society.



A cloud is a visible mass of droplets or frozen crystals floating in the atmosphere above the surface of the Earth or another planetary body. A cloud is also a visible mass attracted by gravity (clouds can also occur as masses of material in interstellar space, where they are called interstellar clouds and nebulae.) The branch of meteorology in which clouds are studied is nephology.

On Earth the condensing substance is typically water vapor, which forms small droplets or ice crystals, typically 0.01 mm in diameter. When surrounded by billions of other droplets or crystals they become visible as clouds. Dense deep clouds exhibit a high reflectance (70% to 95%) throughout the visible range of wavelengths: they thus appear white, at least from the top. Cloud droplets tend to scatter light efficiently, so that the intensity of the solar radiation decreases with depth into the gases, hence the gray or even sometimes dark appearance of the clouds at their base.
Thin clouds may appear to have acquired the color of their environment or background, and clouds illuminated by non-white light, such as during sunrise or sunset, may be colored accordingly. In the near-infrared range, clouds would appear darker because the water that constitutes the cloud droplets strongly absorbs solar radiation at those wavelengths.


High clouds (Family A)

These generally form above 20,000 feet (6,000 m), in the cold region of the troposphere. In Polar regions, they may form as low as 16,500 ft (5,030 m); they are denoted by the prefix cirro- or cirrus. At this altitude, water frequently freezes so clouds are composed of ice crystals. The clouds tend to be wispy and are often transparent.

Clouds in Family A include:

    * Cirrocumulus (Cc)NICE CLOUDS
    * Cirrostratus (Cs)
    * Cirrus (Ci)
    * Cirrus Kelvin-Helmholtz Colombia
    * Cirrus uncinus
    * Contrail, a long thin cloud which develops as the result of the passage of an aircraft at high altitudes.

    * Pileus

Middle clouds (Family B)

These develop between 2,000 and 6,000 m (between 6,500 and 20,000 feet) and are denoted by the prefix alto-. They are made of water droplets and are frequently supercooled.

Clouds in Family B include:

    * Altocumulus (Ac)
    * Altocumulus castellanus
    * Altocumulus lenticularis
    * Altocumulus mackerel sky
    * Altocumulus undulatus
    * Altostratus (As)
    * Altostratus undulatus

Low clouds (Family C)

These are found up to 2,000 m (6,500 feet) and include the stratus (dense and grey). When stratus clouds contact the ground, they are called fog.

Clouds in Family C include:

    * Cumulus humilis (Cu)
    * Cumulus mediocris (Cu)
    * Nimbostratus (Ns)
    * Stratocumulus (Sc)
    * Stratus (St)

Vertical clouds (Family D)

These clouds can have strong up-currents, rise far above their bases and form at many heights.

Clouds in Family D include:

    * Cumulonimbus (associated with heavy precipitation and thunderstorms) (Cb)
    * Cumulonimbus calvus
    * Cumulonimbus incus
    * Cumulonimbus with mammatus
    * Cumulus congestus
    * Pyrocumulus
ratu says:
Ha ha ha
This is a clouds lesson!
Posted on: Sep 11, 2008
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photo by: breezejen