CAPTIVATIING CLOUDS

CLOUDS:

Scientists say clouds form when relatively warm air containing water vapour cools as it rises. They define a cloud as, "a visible mass of condensed droplets or frozen crystals suspended in the atmosphere above the Earth's surface." Each droplet has a diameter of about a hundredth of a millimeter and one cubic meter of air may contain as many as 100 million droplets. Because the droplets are so small, they can remain liquid even at minus 30 degree centigrade and are then called super cooled droplets.

CRUISE CONTROL:

Clouds can be classified depending on the altitude at which they cruise along.

High clouds (Family A):These generally form above 5000m and at around 3000m in Polar Regions. Water freezes at this altitude, so these clouds are composed of ice crystals. These clouds are typically wispy, transparent and white. But they display Nature's amazing palette of colours when the Sun is low on the horizon.
Middle clouds (Family B):These develop at altitudes between 2000 m and 5000 m and are made up of water droplets, often super cooled.
Low clouds (Family C):These are found at altitudes up to 2000 m and are mostly composed of water droplets. However, when temperatures are cold enough, they may also contain ice particles and snow.
Vertical clouds (Family D):These clouds form at variable heights and can grow to heights in excess of 12000 meters.

CLOUD CLASSIFICATION:

In 1803, Like Howard recognized four types of clouds:
* Cumulus (meaning in a pile)
* Stratus (meaning in a layer)
* Cirrus(thread-like)
* Nimbus (rain bearer)
A new catagory called Alto was later added as a prefix given to mid-level clouds.

CLOUD CATEGORIES:

Today there are ten main cloud types, which are further divided in to 27 sub-types.
1. Cirrus: Also called mare's Tail. White, resembling delicate hair-like filaments. They may also appear in dense patches; or occasionally in parallel bands that appear to converge towards the horizon. Associated with ice crystals, these clouds are signs of unsettled weather.
2. Cirrocumulus: High altitude clouds; associated with ice crystals but no rain.
3. Cirrostratus: High altitude clouds appearing like a transparent sheet; associated with ice crystals but no precipitation.
4. Altocumulus: Middle altitude, layered cloud, generally white with some shading; sometimes associate with light showers.
5. Altostratus: Middle altitude, grey cloud; associated with rain or snow.
6. Nimbostratus: Thick, dark cloud; associated with heavy rain or snow.
7. Stratocumulus: Low altitude, layered cloud, generally white; associated with light drizzle.
8. Stratus: Low altitude, grey coloured cloud; associated with drizzle. If ragged in apppearence it is called Fractostratus.
9. Cumulus: Low altitude cloud associated with rain or snow. They appear white when sunlit but have darker undersides anda distinctive ' cauliflower'
10. Cumulonimbus: Low altitude clouds that can reach 16km in height; associated with thunderstorm, lightning, squalls, and showers of rain or snow.