Radojica
06-19-2010, 10:42 PM
Cloud types are divided into two general categories: layered and convective. These names distinguish a cloud's altitude. Clouds are classified by the base height, not the cloud top, and bases may differ depending on the geographical zones, from lowest level ove rpolar regions to the highest altitude over equatorial zone. This system was proposed in 1802, when it was presented to the Askesian society by Luke Horward.
High clouds (Family A)
High clouds will form between 10,000 and 25,000 ft (3,000 and 8,000 m) in the polar regions, 16,500 and 40,000 ft (5,000 and 12,000 m) in the temperate zone and 20,000 and 60,000 ft (6,000 and 18,000 m) in the tropical (equatorial region).
Clouds in Family A include:
Cirrocumulus (Cc)
Cirrus (Ci)
Cirrostratus (Cs)
Middle clouds (Family B)
Middle clouds tend to form at 6,500 ft (2,000 m) but may form at heights up to 13,000 ft (4,000 m), 23,000 ft (7,000 m) or 25,000 ft (8,000 m) depending on the region.Nimbostratus clouds are sometimes included with the middle clouds, but due to the fact that their lower base is sometimes under 100 meters, it is also consider to belong to low clouds.
Clouds in Family B include:
Altostratus (As)
Altocumulus (Ac)
Low clouds (Family C)
These are found up to 6,500 ft (2,000 m)and include the stratus (dense and grey). When stratus clouds contact the ground, they are called fog.
Clouds in Family C include:
Cumulus (Cu)
Cumulus humilis
Cumulus mediocris
Stratocumulus (Sc)
Nimbostratus(Ns)
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:
Cumulunimbus (associated with heavy precipitation and thunderstorms) (Cb) Cumulunimbus calvus
Cumulunimbus incus
Cumulunimbus mammutus
The color of a cloud
The color of a cloud, as seen from the Earth, tells much about what is going on inside the cloud. Clouds form because warm air tends to absorb water vapor, which is lighter than air, thus helping the mixture to rise. As it rises the air containing it cools and the vapor tends to condense out of the air as micro-droplets. These tiny particles of water are densely packed and sunlight cannot penetrate far into the cloud before it is reflected out, giving a cloud its characteristic white color. As a cloud matures, the dense water droplets may combine to produce larger droplets, which may combine to form droplets large enough to fall as rain. By this process of accumulation, the space between droplets becomes increasingly larger, permitting light to penetrate farther into the cloud. If the cloud is sufficiently large and the droplets within are spaced far enough apart, it may be that a percentage of the light which enters the cloud is not reflected back out before it is absorbed. A simple example of this is being able to see farther in heavy rain than in heavy fog. This process of reflection/absorption is what causes the range of cloud color from white to black. For the same reason, the undersides of large clouds and heavy overcasts can appear as various degrees of grey shades, depending on how much light is being reflected or transmitted back to the observer.
Other colors occur naturally in clouds. Bluish-grey is the result of light scattering within the cloud. In the visible spectrum, blue and green are at the short end of light's visible wavelengths, while red and yellow are at the long end. The short rays are more easily scattered by water droplets, and the long rays are more likely to be absorbed. The bluish color is evidence that such scattering is being produced by rain-sized droplets in the cloud.
A greenish tinge to a cloud is produced when sunlight is scattered by ice. A cumulonimbus cloud emitting green is an imminent sign of heavy rain,hail, strong winds and possible tornadoes.
Yellowish clouds are rare but may occur in the late spring through early fall months during forest fire season. The yellow color is due to the presence of pollutants in the smoke.
Red, orange and pink clouds occur almost entirely at sunrise/sunset and are the result of the scattering of sunlight by the atmosphere. The clouds do not become that color; they are reflecting long and unscattered rays of sunlight, which are predominant at those hours. The effect is much like if one were to shine a red spotlight on a white sheet. In combination with large, mature thunderheads this can produce blood-red clouds.
Clouds in Family A include:
http://www.cloudman.com/gallery1/photos/176.jpg
http://www.cloudman.com/gallery1/photos/177.jpg
http://www.cloudman.com/gallery1/photos/179.jpg
http://www.cloudman.com/gallery1/photos/182.jpg
http://www.cloudman.com/gallery1/photos/197.jpg
http://www.cloudman.com/gallery1/photos/196.jpg
http://www.cloudman.com/gallery1/photos/200.jpg
(last three are Cirrostratus)
Clouds in Family B include:
http://upload.wikimedia.org/wikipedia/commons/4/4a/AltostratusClouds.jpg
http://www.cloudman.com/gallery1/photos/159.jpg
http://www.cloudman.com/gallery1/photos/160.jpg
http://www.cloudman.com/gallery1/photos/162.jpg
http://www.cloudman.com/gallery1/photos/164.jpg
http://www.cloudman.com/gallery1/photos/165.jpg
Low clouds (Family C)
http://www.cloudman.com/gallery1/photos/101.jpg
http://www.cloudman.com/gallery1/photos/102.jpg
http://www.cloudman.com/gallery1/photos/106.jpg
http://www.cloudman.com/gallery1/photos/108.jpg
http://www.cloudman.com/gallery1/photos/107.jpg
http://www.cloudman.com/gallery1/photos/151.jpg
http://www.cloudman.com/gallery1/photos/153.jpg
http://asd-www.larc.nasa.gov/SCOOL/Clouds/nimbostratus12.JPG
http://upload.wikimedia.org/wikipedia/commons/2/27/Nimbostratus_praecipitatio.JPG
(Nimbostratuses).
Vertical clouds (Family D)
http://upload.wikimedia.org/wikipedia/commons/3/39/Cumulonimbus_NOAA_gov.jpg
http://upload.wikimedia.org/wikipedia/commons/9/98/Anvil_shaped_cumulus_panorama_edit_crop.jpg
http://upload.wikimedia.org/wikipedia/commons/4/4b/CloudOverUtah.jpg
http://upload.wikimedia.org/wikipedia/commons/8/82/Wagga-Cumulonimbus.jpg
http://upload.wikimedia.org/wikipedia/commons/0/04/Wagga-cb-7dec05.jpg
http://upload.wikimedia.org/wikipedia/commons/2/2b/CumulonimbusFlorida.jpg
http://upload.wikimedia.org/wikipedia/commons/e/ea/Anvil_cumulus_feb_2007.jpg
http://upload.wikimedia.org/wikipedia/en/0/0a/Cumulonimbus_incus_cloud_Jan2008.jpg
http://upload.wikimedia.org/wikipedia/commons/6/65/Cumulonimbus-incus_mykonos.jpg
http://upload.wikimedia.org/wikipedia/en/e/ed/Middleeastmamatus.JPG
http://upload.wikimedia.org/wikipedia/commons/7/7c/Mammatus-storm-clouds_San-Antonio.jpg
http://www.cloudman.com/gallery1_1.html
http://en.wikipedia.org/wiki/Cloud
High clouds (Family A)
High clouds will form between 10,000 and 25,000 ft (3,000 and 8,000 m) in the polar regions, 16,500 and 40,000 ft (5,000 and 12,000 m) in the temperate zone and 20,000 and 60,000 ft (6,000 and 18,000 m) in the tropical (equatorial region).
Clouds in Family A include:
Cirrocumulus (Cc)
Cirrus (Ci)
Cirrostratus (Cs)
Middle clouds (Family B)
Middle clouds tend to form at 6,500 ft (2,000 m) but may form at heights up to 13,000 ft (4,000 m), 23,000 ft (7,000 m) or 25,000 ft (8,000 m) depending on the region.Nimbostratus clouds are sometimes included with the middle clouds, but due to the fact that their lower base is sometimes under 100 meters, it is also consider to belong to low clouds.
Clouds in Family B include:
Altostratus (As)
Altocumulus (Ac)
Low clouds (Family C)
These are found up to 6,500 ft (2,000 m)and include the stratus (dense and grey). When stratus clouds contact the ground, they are called fog.
Clouds in Family C include:
Cumulus (Cu)
Cumulus humilis
Cumulus mediocris
Stratocumulus (Sc)
Nimbostratus(Ns)
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:
Cumulunimbus (associated with heavy precipitation and thunderstorms) (Cb) Cumulunimbus calvus
Cumulunimbus incus
Cumulunimbus mammutus
The color of a cloud
The color of a cloud, as seen from the Earth, tells much about what is going on inside the cloud. Clouds form because warm air tends to absorb water vapor, which is lighter than air, thus helping the mixture to rise. As it rises the air containing it cools and the vapor tends to condense out of the air as micro-droplets. These tiny particles of water are densely packed and sunlight cannot penetrate far into the cloud before it is reflected out, giving a cloud its characteristic white color. As a cloud matures, the dense water droplets may combine to produce larger droplets, which may combine to form droplets large enough to fall as rain. By this process of accumulation, the space between droplets becomes increasingly larger, permitting light to penetrate farther into the cloud. If the cloud is sufficiently large and the droplets within are spaced far enough apart, it may be that a percentage of the light which enters the cloud is not reflected back out before it is absorbed. A simple example of this is being able to see farther in heavy rain than in heavy fog. This process of reflection/absorption is what causes the range of cloud color from white to black. For the same reason, the undersides of large clouds and heavy overcasts can appear as various degrees of grey shades, depending on how much light is being reflected or transmitted back to the observer.
Other colors occur naturally in clouds. Bluish-grey is the result of light scattering within the cloud. In the visible spectrum, blue and green are at the short end of light's visible wavelengths, while red and yellow are at the long end. The short rays are more easily scattered by water droplets, and the long rays are more likely to be absorbed. The bluish color is evidence that such scattering is being produced by rain-sized droplets in the cloud.
A greenish tinge to a cloud is produced when sunlight is scattered by ice. A cumulonimbus cloud emitting green is an imminent sign of heavy rain,hail, strong winds and possible tornadoes.
Yellowish clouds are rare but may occur in the late spring through early fall months during forest fire season. The yellow color is due to the presence of pollutants in the smoke.
Red, orange and pink clouds occur almost entirely at sunrise/sunset and are the result of the scattering of sunlight by the atmosphere. The clouds do not become that color; they are reflecting long and unscattered rays of sunlight, which are predominant at those hours. The effect is much like if one were to shine a red spotlight on a white sheet. In combination with large, mature thunderheads this can produce blood-red clouds.
Clouds in Family A include:
http://www.cloudman.com/gallery1/photos/176.jpg
http://www.cloudman.com/gallery1/photos/177.jpg
http://www.cloudman.com/gallery1/photos/179.jpg
http://www.cloudman.com/gallery1/photos/182.jpg
http://www.cloudman.com/gallery1/photos/197.jpg
http://www.cloudman.com/gallery1/photos/196.jpg
http://www.cloudman.com/gallery1/photos/200.jpg
(last three are Cirrostratus)
Clouds in Family B include:
http://upload.wikimedia.org/wikipedia/commons/4/4a/AltostratusClouds.jpg
http://www.cloudman.com/gallery1/photos/159.jpg
http://www.cloudman.com/gallery1/photos/160.jpg
http://www.cloudman.com/gallery1/photos/162.jpg
http://www.cloudman.com/gallery1/photos/164.jpg
http://www.cloudman.com/gallery1/photos/165.jpg
Low clouds (Family C)
http://www.cloudman.com/gallery1/photos/101.jpg
http://www.cloudman.com/gallery1/photos/102.jpg
http://www.cloudman.com/gallery1/photos/106.jpg
http://www.cloudman.com/gallery1/photos/108.jpg
http://www.cloudman.com/gallery1/photos/107.jpg
http://www.cloudman.com/gallery1/photos/151.jpg
http://www.cloudman.com/gallery1/photos/153.jpg
http://asd-www.larc.nasa.gov/SCOOL/Clouds/nimbostratus12.JPG
http://upload.wikimedia.org/wikipedia/commons/2/27/Nimbostratus_praecipitatio.JPG
(Nimbostratuses).
Vertical clouds (Family D)
http://upload.wikimedia.org/wikipedia/commons/3/39/Cumulonimbus_NOAA_gov.jpg
http://upload.wikimedia.org/wikipedia/commons/9/98/Anvil_shaped_cumulus_panorama_edit_crop.jpg
http://upload.wikimedia.org/wikipedia/commons/4/4b/CloudOverUtah.jpg
http://upload.wikimedia.org/wikipedia/commons/8/82/Wagga-Cumulonimbus.jpg
http://upload.wikimedia.org/wikipedia/commons/0/04/Wagga-cb-7dec05.jpg
http://upload.wikimedia.org/wikipedia/commons/2/2b/CumulonimbusFlorida.jpg
http://upload.wikimedia.org/wikipedia/commons/e/ea/Anvil_cumulus_feb_2007.jpg
http://upload.wikimedia.org/wikipedia/en/0/0a/Cumulonimbus_incus_cloud_Jan2008.jpg
http://upload.wikimedia.org/wikipedia/commons/6/65/Cumulonimbus-incus_mykonos.jpg
http://upload.wikimedia.org/wikipedia/en/e/ed/Middleeastmamatus.JPG
http://upload.wikimedia.org/wikipedia/commons/7/7c/Mammatus-storm-clouds_San-Antonio.jpg
http://www.cloudman.com/gallery1_1.html
http://en.wikipedia.org/wiki/Cloud