CLOUDS FORMATION AND CLASSIFICATION OF CLOUDS
This article will clearly explain about Clouds and Classification of clouds.
- Clouds/clouds are defined as aggregates of several tiny water droplets, ice particles or a mixture of both in the air generally much above the ground surface.
- Not all clouds produce precipitation, but precipitation will not occur without the formation of a cloud first.
- Clouds are important factors in the heat energy budget.
- They absorb some of the incoming solar energy, reflect some of that energy back to space and scatter or diffuse other wavelengths of energy to and away from Earth.
- Clouds form when air happens to cool, to dew point and vapour condenses in Water droplet and or ice crystals.
- Two conditions are necessary for cloud formation.They are
- Air must be Saturated. (When air of given temperature holds all of the Water Vapour that it possibly can it is said to be in a state of saturation).
- There must be a substantial quantity of small particles called Condensation nuclei, around which liquid droplets/ ice crystals are formed when vapour condenses.
- Cloud indicates the state of Atmosphere and whisper hints about the future weather.
CLASSIFICATION OF CLOUDS
- The general classification of clouds was proposed by Luke Howard in 1803.
- Howard’s Classification was a descriptive one and based on the shape of height.
CLASSIFICATION OF CLOUDS BASED ON SHAPE
Howard recognised three standard shapes of clouds and used three Latin words for the same.
(1) Cirrus Clouds – Like a lock of curly hair.
- Cirrus clouds form at very high altitudes, normally 6000-10,000 m, and are made up of ice crystals.
(2) Stratus Clouds – Like a sheet/layer/ceiling of a room.
- Stratus clouds appear at lower altitudes from the surface up to almost 6000 m.
- The basic characteristic of stratus clouds is their horizontal appearance, in layers of fairly uniform thickness.
(3) Cumulus Clouds – Like a heap/pile.
- Cumulus clouds develop vertically rather than forming the more horizontal structures of the cirrus and stratus types.
- Cumulus clouds provide visible evidence of an unstable atmosphere.
- He also used the word Nimbus to denote a rain bearing cloud.
CLASSIFICATION OF CLOUDS BASED ON HEIGHT
(1). HEIGHT AT WHICH A CLOUD IS FORMED.
There are three subtypes.
1) High clouds(Cirro): Clouds formed at an elevation above 20000 feet(7000 meters).
2) Low Clouds(Strato): Clouds formed at an elevation below 2000 meters (7000 feet).
3) Middle Clouds(Alto): The ones which are formed at elevations between 2000 – 7000 meters. I.e between 7000-2000 feet.
(2). CLOUDS WITH GREAT VERTICAL EXTENT.
- Such clouds grow from low bases to a height of as much as 15 km (above 50,000 ft).
- Such clouds usually have limited horizontal spread (As they are related to localised heating (or) convection).
- High clouds are mainly cirrus in shape.
- Low clouds are mainly stratus in shape.
- Clouds which are vertically developed are mainly cumulus in shape.
- Howard used the word Alto as the prefix to denote a middle-level cloud.
- High clouds are composed largely of Ice crystals.
- Supercooled droplets refer to the microscopic droplets of water at the temperature below 0 degrees C.
- Middle-level clouds are hugely formed of water droplets which frequently exists in a supercooled State at the temperature well below freezing.
- Howard also made composite names using the above-mentioned Latin words such as Cumulonimbus Nimbus and cirrostratus.