PRESENTED BYM. Fasihud Din Nauman

(Roll. No: 29)Environmental Science

(4TH- Semester)

Clouds

visible mass of liquid droplets or visible mass of liquid droplets or frozen crystals made of water and/or frozen crystals made of water and/or

aerosols is called aerosols is called cloud.cloud.

Cloud LocationCloud Location

Majority of clouds form in the Majority of clouds form in the TROPOSPHERETROPOSPHERE

Clouds can be observed in Clouds can be observed in STRATOSPHERE STRATOSPHERE and MESOSPHEREand MESOSPHERE

Three layers of atmosphere collectively called Three layers of atmosphere collectively called HOMOSPHEREHOMOSPHERE where clouds are presentwhere clouds are present

Clouds are absent in the Clouds are absent in the HETROSPHEREHETROSPHERE (Thermosphere and Exosphere)(Thermosphere and Exosphere)

CLOUD FORMATIONCLOUD FORMATION Warm air is forced upward, expands then Warm air is forced upward, expands then

cools.cools. As air cools the amount of water vapor needed As air cools the amount of water vapor needed

for saturation decreases (RH then increases).for saturation decreases (RH then increases). RH of 100%, air is saturatedRH of 100%, air is saturated Water vapor begins to condense in tiny drops Water vapor begins to condense in tiny drops

around nuclei of dust, salt, and other particles.around nuclei of dust, salt, and other particles. Drops of water are so small they are Drops of water are so small they are

suspended in air.suspended in air. Millions of these droplets collect forming Millions of these droplets collect forming

clouds.clouds.

CLOUDS CLASSIFICATIONCLOUDS CLASSIFICATION

There are following components which There are following components which summarize the classification system.summarize the classification system.

♣ ♣ Cirro Cirro :: curl of hair, high curl of hair, high

♣ ♣ Alto Alto :: mid mid

♣ ♣ Strato Strato :: layer layer

♣ ♣ Nimbo Nimbo : : rain, precipitation rain, precipitation

♣♣ CumuloCumulo:: heap heap

CLOUD CLOUD CLASSIFICATIONCLASSIFICATION

SHAPSHAPEE

CumulCumulususStratuStratussCirrusCirrus

: cotton ball shaped : forms a blanket over large areas.: feathery or wispy

•Clouds are classified by texture and height from the ground.

4 Major families of Clouds4 Major families of Clouds

A.A. High Clouds High Clouds : : above 5-13 km.above 5-13 km.

B.B. Middle Clouds Middle Clouds : : 2-7 km.2-7 km.

C.C. Low Clouds Low Clouds : : 0-2 km.0-2 km.

D.D. Clouds with vertical developmentClouds with vertical development (0-13 km)(0-13 km)

Cloud TypesCloud Types

TYPES OF CLOUDSTYPES OF CLOUDS

♦♦ High-level clouds:High-level clouds: ♣ ♣ cirrus cirrus ♣ ♣ cirrostratus cirrostratus ♣ ♣ cirrocumulus cirrocumulus

♦♦ Mid-level clouds:Mid-level clouds: ♣ ♣ altostratus altostratus ♣ ♣ altocumulusaltocumulus

♦ ♦ Low-level clouds:Low-level clouds: ♣ ♣ stratus stratus ♣ ♣ cumulus cumulus

HIGH-LEVEL HIGH-LEVEL CLOUDSCLOUDS

High Clouds (Family A)High Clouds (Family A)

Composed of ice crystals Composed of ice crystals (Cirrostratus)(Cirrostratus) Thin and wispy Thin and wispy (Cirrus)(Cirrus)

High Clouds Cont…High Clouds Cont…

High-level clouds form above 6 km High-level clouds form above 6 km The temperatures are so cold at such high The temperatures are so cold at such high

elevations, these clouds are primarily elevations, these clouds are primarily composed of ice crystals. composed of ice crystals.

High-level clouds are typically thin and High-level clouds are typically thin and white in appearance, but can appear in a white in appearance, but can appear in a magnificent array of colors when the sun magnificent array of colors when the sun is low on the horizon.is low on the horizon.

CIRRUSThin, featherlike clouds that are made of ice

crystals high in the atmosphere. Usually means a change in the weather is coming.

High Clouds Cont…High Clouds Cont…

Cirrus (Thin and wispy)Cirrus (Thin and wispy) The most common form of high-level clouds are thin The most common form of high-level clouds are thin

and often wispy cirrus clouds. and often wispy cirrus clouds. Typically found at heights greater than 20,000 feet Typically found at heights greater than 20,000 feet

(6,000 meters)(6,000 meters) cirrus clouds are composed of ice crystals that cirrus clouds are composed of ice crystals that

originate from the freezing of supercooled water originate from the freezing of supercooled water droplets. droplets.

Cirrus generally occur in fair weather and point in Cirrus generally occur in fair weather and point in the direction of air movement at their elevation.the direction of air movement at their elevation.

CIRROSTRATUSCIRROSTRATUS

CIRROSTRATUSCIRROSTRATUSCirrostratus clouds form more of a Cirrostratus clouds form more of a

widespread, veil-like layer. When moon or widespread, veil-like layer. When moon or sun light passes through the ice crystals of sun light passes through the ice crystals of cirrostratus clouds, the light may dispersed.cirrostratus clouds, the light may dispersed.

High Clouds Cont…High Clouds Cont… Cirrostratus (nearly transparent) Cirrostratus (nearly transparent) Sheet-like, clouds composed of ice crystals.Sheet-like, clouds composed of ice crystals. Though cirrostratus can cover the entire sky and be up to several Though cirrostratus can cover the entire sky and be up to several

thousand feet thickthousand feet thick They are relatively transparent, as the sun or the moon can easily They are relatively transparent, as the sun or the moon can easily

be seen through them. be seen through them. These high-level clouds typically form when a broad layer of air is These high-level clouds typically form when a broad layer of air is

lifted by large-scale Convergencelifted by large-scale Convergence   Its presence indicates a large amount of moisture in the Its presence indicates a large amount of moisture in the

upper atmosphereupper atmosphere These are not precipitation clouds, but signal the approach of These are not precipitation clouds, but signal the approach of

warm frontwarm front

CIRROCUMULUSCIRROCUMULUS

High Clouds Cont…High Clouds Cont…

Cirrocumulus (Cloudlets) (Cc)Cirrocumulus (Cloudlets) (Cc) Typically found at heights 5 to 12 km.Typically found at heights 5 to 12 km. These clouds signify convectionThese clouds signify convection It includes . It includes . Cirrocumulus usually only forms in patchesCirrocumulus usually only forms in patches

MID-LEVEL MID-LEVEL CLOUDSCLOUDS

MidMid-Level -Level CloudsClouds

Composed of water droplets and ice Composed of water droplets and ice crystalscrystals

ALTOSTRATUSALTOSTRATUS

ALTOSTRATUS CLOUDSALTOSTRATUS CLOUDS Altostratus clouds “strato” type clouds Altostratus clouds “strato” type clouds

having flat and uniform type texture.having flat and uniform type texture. Altostratus clouds themselves do not Altostratus clouds themselves do not

produce precipitation at the surface.produce precipitation at the surface. They frequently indicate warm wave front.They frequently indicate warm wave front.

Altocumulus CloudsAltocumulus Clouds

LOW-LEVEL LOW-LEVEL CLOUDSCLOUDS

Low-Level CloudsLow-Level Clouds

Composed mostly of water dropletsComposed mostly of water droplets

STRATUSSheets of low, grey clouds that bring light

snow, rain, or drizzle.

NIMBOSTRATUSNIMBOSTRATUS

NIMBOSTRATUSThicker layer than stratus clouds that

completely block out the sun. They cause steady rain or snow.

CUMULUSWhite and puffy clouds that usually

mean good weather.

CUMULONIMBUSCUMULONIMBUS

CUMULONIMBUSDark, towering clouds that are also called “thunderheads”. These clouds produce heavy rain, thunderstorm, and lighting.

Cumulonimbus

Process by which water falls to Earth from clouds in the

atmosphere in the form of rain, snow, sleet, or hail.

PRECIPITATIONPRECIPITATION

TYPES OF TYPES OF PRECIPITATIOPRECIPITATIO

NN

As raindrops fall from the clouds they

join with other

droplets of water.

This causes the

raindrops to grow in size.