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Cloud Identification Images & Info from: n/secondary/teachers/clouds.html.

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Cloud Identification Cloud Identification Images & Info from: Images & Info from: http:// http:// www.metoffice.com/ www.metoffice.com/ education/secondary/ education/secondary/ teachers/clouds.html teachers/clouds.html
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Cloud IdentificationCloud Identification

Images & Info from:Images & Info from:

http://www.metoffice.com/http://www.metoffice.com/education/secondary/teachers/education/secondary/teachers/

clouds.htmlclouds.html

4 types of clouds4 types of clouds Howard recognized Howard recognized

four types of cloud four types of cloud and gave them the and gave them the following Latin following Latin names.names.

CumulusCumulus — heaped — heaped or in a pile or in a pile

StratusStratus — in a sheet — in a sheet or layer or layer

CirrusCirrus — thread-like, — thread-like, hairy or curled hairy or curled

NimbusNimbus — a rain — a rain bearer bearer

In 1803 a retail In 1803 a retail chemist and chemist and amateur amateur meteorologist meteorologist called Luke called Luke Howard began Howard began classifying clouds. classifying clouds. His classifications His classifications have become the have become the basis of how basis of how clouds are still clouds are still classified.classified.

3 groups 3 groups

The cloud types are split into three groups The cloud types are split into three groups according to the height of their base above according to the height of their base above sea level. Note that 'medium' level clouds sea level. Note that 'medium' level clouds are prefixed by the word are prefixed by the word altoalto and 'high' and 'high' clouds by the word clouds by the word cirrocirro (see Table 1). All (see Table 1). All heights given are approximate above sea heights given are approximate above sea level in mid-latitudes. If looking at them from level in mid-latitudes. If looking at them from a hill top or mountain site, the range of a hill top or mountain site, the range of bases will be lower. bases will be lower.

Cloud HeightCloud Height

Low cloudsLow cloudsMedium Medium

cloudsclouds High cloudsHigh clouds

Surface - Surface - 7,000 ft7,000 ft

7,000 - 17,000 7,000 - 17,000 ftft

17,000 - 17,000 - 35,000 ft35,000 ft

CumulusCumulus AltocumulusAltocumulus CirrusCirrus

CumulonimbusCumulonimbus AltostratusAltostratus CirrostratusCirrostratus

StratusStratus CirrocumulusCirrocumulus

StratocumulusStratocumulus

NimbostratusNimbostratus      

Low Level CloudsLow Level Clouds

Surface - 7,000 ftSurface - 7,000 ft

CumulusCumulus CumulonimbusCumulonimbus

StratusStratus StratocumulusStratocumulus NimbostratusNimbostratus

FogFog

Cumulus (Cu)Cumulus (Cu)

Height of base: Height of base: 1,200–6,000 ft 1,200–6,000 ft Color:Color: White on its sunlit parts but with White on its sunlit parts but with darker undersides. darker undersides. Shape:Shape: This cloud appears in the form of This cloud appears in the form of detached heaps. Large cumulus clouds detached heaps. Large cumulus clouds have a distinctive 'cauliflower' shape. have a distinctive 'cauliflower' shape. Other features:Other features: Well developed cumulus Well developed cumulus may produce rain showers. may produce rain showers.

Cumulus (Cu)

Cumulonimbus (Cb) Cumulonimbus (Cb)

Height of base:Height of base: 1,000–5,000 ft 1,000–5,000 ft Color:Color: White upper parts with dark, threatening White upper parts with dark, threatening undersides. undersides. Shape:Shape: A very tall cumulus-type cloud. When the A very tall cumulus-type cloud. When the top of a cumulus gets up high enough, the water top of a cumulus gets up high enough, the water drops are transformed into ice crystals and it loses drops are transformed into ice crystals and it loses its clear, sharp outline. At this stage the cloud has its clear, sharp outline. At this stage the cloud has become a cumulonimbus. Often, the cloud top become a cumulonimbus. Often, the cloud top spreads out into a distinctive wedge or anvil spreads out into a distinctive wedge or anvil shape. shape. Other features:Other features: Accompanied by heavy showers, Accompanied by heavy showers, perhaps with hail and thunder. perhaps with hail and thunder.

Cumulonimbus (Cb)

Stratus (St)Stratus (St)

Height of base:Height of base: surface–1,500 ft surface–1,500 ft Color:Color: Usually grey. Usually grey. Shape:Shape: May appear as a layer with a fairly uniform base or May appear as a layer with a fairly uniform base or in ragged patches, especially when precipitation falls from in ragged patches, especially when precipitation falls from a cloud layer above. Fog will often lift into a layer of stratus a cloud layer above. Fog will often lift into a layer of stratus due to an increase in wind or rise in temperature. As the due to an increase in wind or rise in temperature. As the sun heats the ground the base of stratus cloud may rise sun heats the ground the base of stratus cloud may rise and break becoming shallow cumulus cloud as its edges and break becoming shallow cumulus cloud as its edges take on a more distinctive form. take on a more distinctive form. Other features:Other features: If thin, the disc of the sun or moon will be If thin, the disc of the sun or moon will be visible (providing there are no other cloud layers above). If visible (providing there are no other cloud layers above). If thick, it may produce drizzle or snow grains. thick, it may produce drizzle or snow grains.

Stratus (St)

Stratocumulus (Sc) Stratocumulus (Sc)

Height of base: Height of base: 1,200–7,000 ft 1,200–7,000 ft Color:Color: Grey or white, generally with Grey or white, generally with shading. shading. Shape:Shape: Either patches or a sheet of Either patches or a sheet of rounded elements. rounded elements. Other features: Other features: May produce light rain or May produce light rain or snow. Sometimes the cloud may result from snow. Sometimes the cloud may result from the spreading out of cumulus, giving a light the spreading out of cumulus, giving a light shower. shower.

Stratocumulus (Sc)

Nimbostratus (Ns)Nimbostratus (Ns)

Height of base:Height of base: 1,500–10,000 ft 1,500–10,000 ft Colour: Colour: Dark grey. Dark grey. Shape: Shape: A thick, diffuse layer covering all or most A thick, diffuse layer covering all or most of the sky. of the sky. Other features: Other features: Sun or moon always blotted out. Sun or moon always blotted out. Accompanied by moderate or heavy rain or snow, Accompanied by moderate or heavy rain or snow, occasionally ice pellets. Although classed as a low occasionally ice pellets. Although classed as a low cloud level at its base, its top frequently rises to cloud level at its base, its top frequently rises to high cloud levels. high cloud levels.

Nimbostratus (Ns)

Medium Level CloudsMedium Level Clouds

7,000 - 17,000 ft7,000 - 17,000 ft

AltocumulusAltocumulus AltostratusAltostratus

Altocumulus (Ac) Altocumulus (Ac) Height of base:Height of base: 7,000–17,000 ft 7,000–17,000 ft Color:Color: Grey or white, generally with some shading. Grey or white, generally with some shading.

Shape:Shape: Several different types, the most common being Several different types, the most common being either patches or a sheet of rounded elements but may either patches or a sheet of rounded elements but may also appear as a layer without much form. also appear as a layer without much form.

Other features:Other features: Occasionally some slight rain or snow, Occasionally some slight rain or snow, perhaps in the form of a shower may reach the ground. perhaps in the form of a shower may reach the ground. On rare occasions, a thunderstorm may occur. On rare occasions, a thunderstorm may occur.

Altocumulus (Ac)

Altostratus (As)Altostratus (As)

Height of base:Height of base: 8,000–17,000 ft 8,000–17,000 ft Color: Color: Greyish or bluish. Greyish or bluish. Shape:Shape: A sheet of uniform appearance totally or A sheet of uniform appearance totally or partly covering the sky. partly covering the sky. Other features: Other features: Sometimes thin enough to reveal Sometimes thin enough to reveal the sun or moon vaguely, as through ground glass. the sun or moon vaguely, as through ground glass. Objects on the ground do not cast shadows. May Objects on the ground do not cast shadows. May give generally light rain or snow, occasionally ice give generally light rain or snow, occasionally ice pellets, if the cloud base is no higher than about pellets, if the cloud base is no higher than about 10,000 ft.10,000 ft.

Altostratus (As)

High Level CloudsHigh Level Clouds

17,000 - 35,000 ft17,000 - 35,000 ft

CirrusCirrus CirrostratusCirrostratus

CirrocumulusCirrocumulus ContrailsContrails

Cirrus (Ci) Cirrus (Ci)

Height of base: Height of base: 17,000–35,000 ft 17,000–35,000 ft Colour: Colour: Composed of ice crystals, therefore Composed of ice crystals, therefore white. white. Shape:Shape: Delicate hair-like filaments, Delicate hair-like filaments, sometimes hooked at the end.sometimes hooked at the end.Other features: Other features: The remains of the upper The remains of the upper portion of a cumulonimbus is also classified portion of a cumulonimbus is also classified as cirrus. as cirrus.

Cirrus (Ci)

Cirrocumulus (Cc) Cirrocumulus (Cc)

Height of base:Height of base: 17,000–35,000 ft 17,000–35,000 ft Colour: Colour: Composed of ice crystals, therefore white. Composed of ice crystals, therefore white.

Shape:Shape: Patches or sheet of very small elements in Patches or sheet of very small elements in the form of grains or ripples or a honeycomb. the form of grains or ripples or a honeycomb. Other features:Other features: Sometimes its appearance in a Sometimes its appearance in a regular pattern of 'waves' and small gaps may regular pattern of 'waves' and small gaps may resemble the scales of a fish, thus giving rise to resemble the scales of a fish, thus giving rise to the popular name 'mackerel sky‘.the popular name 'mackerel sky‘.

Cirrocumulus (Cc)

Cirrostratus (Cs)Cirrostratus (Cs)

Height of base:Height of base: 17,000–35,000 ft 17,000–35,000 ft Colour: Colour: Composed of ice crystals, therefore white. Composed of ice crystals, therefore white. Shape: Shape: A transparent veil of fibrous or smooth A transparent veil of fibrous or smooth appearance totally or partly covering the sky. appearance totally or partly covering the sky. Other features:Other features: Thin enough to allow the sun to Thin enough to allow the sun to cast shadows on the ground unless it is low in the cast shadows on the ground unless it is low in the sky. Produces halo phenomena, the most frequent sky. Produces halo phenomena, the most frequent being the small (22°) halo around the sun or moon being the small (22°) halo around the sun or moon — a little more than the distance between the top — a little more than the distance between the top of the thumb and the little finger spread wide apart of the thumb and the little finger spread wide apart at arm's length.at arm's length.

Cirrostratus (Cs)

ContrailsContrails

Condensation trails (contrails) Condensation trails (contrails) These are thin trails of condensation, These are thin trails of condensation,

formed by the water vapor rushing out from formed by the water vapor rushing out from the engines of jet aircraft flying at high the engines of jet aircraft flying at high altitudes. They are not true clouds, but can altitudes. They are not true clouds, but can remain in the sky for a long time, and grow remain in the sky for a long time, and grow into cirrus clouds.into cirrus clouds.

Contrails

The 4 main ways in which air rises to form The 4 main ways in which air rises to form cloudcloud

1. Rapid local ascent when heated air at the 1. Rapid local ascent when heated air at the earth's surface rises in the form of thermal earth's surface rises in the form of thermal currents (convection).currents (convection).2. Slow, widespread, mass ascent where warm 2. Slow, widespread, mass ascent where warm moist air is undercut by cold air (the barrier moist air is undercut by cold air (the barrier between the warm and cold air is called a 'front').between the warm and cold air is called a 'front').3. Upward motion associated with turbulent eddies 3. Upward motion associated with turbulent eddies resulting from the frictional effect of the earth's resulting from the frictional effect of the earth's surface.surface.4. Air forced to rise over a barrier of mountains or 4. Air forced to rise over a barrier of mountains or hills.hills.

See pictures for explanation on next slide.See pictures for explanation on next slide.

Pictures of the main ways clouds formPictures of the main ways clouds form

Lifetime: less than one hour

Match up the descriptions in column B with the Match up the descriptions in column B with the correct term in column Acorrect term in column A

  

AA BB

CumulusCumulus Rain bearerRain bearer

CirrusCirrus HeapedHeaped

StratusStratus Thread-like or hairyThread-like or hairy

NimbusNimbus Sheets or layersSheets or layers

QuizQuiz

Which of the following are correct statements?Which of the following are correct statements?    (i)   Low clouds form up to 10,000 feet above     (i)   Low clouds form up to 10,000 feet above the surface. the surface.     (ii)  High clouds form between 17,000 and     (ii)  High clouds form between 17,000 and 35,000 feet above the surface. 35,000 feet above the surface.     (iii) Altocumulus and altostratus are two types of     (iii) Altocumulus and altostratus are two types of high cloud. high cloud.     (iv) Nimbostratus is a medium-level cloud.    (iv) Nimbostratus is a medium-level cloud.    (v)  Cumulonimbus is a low cloud.     (v)  Cumulonimbus is a low cloud.


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