Cloud Types and Cloud Types and PrecipitationPrecipitation

CloudsClouds

Clouds among the most striking and Clouds among the most striking and noticeable effects of the atmosphere noticeable effects of the atmosphere and its weather.and its weather.

Clouds are a form of condensation Clouds are a form of condensation best described as visible mixtures of best described as visible mixtures of tiny droplets of water or tiny crystals tiny droplets of water or tiny crystals of ice.of ice.

Clouds show what’s going on in the Clouds show what’s going on in the atmosphere.atmosphere.

Types of CloudsTypes of Clouds

Clouds are classified on the basis of Clouds are classified on the basis of their form and height.their form and height.

The three basic forms are cirrus, The three basic forms are cirrus, cumulus, and stratus.cumulus, and stratus. All other clouds reflect one of these All other clouds reflect one of these

three basic forms or are combinations or three basic forms or are combinations or modifications of them.modifications of them.

Cirrus- (a curl of hair)Cirrus- (a curl of hair) These clouds are high, white, and These clouds are high, white, and

thin, and they occur as patches or thin, and they occur as patches or like sheets.like sheets. Also known as “wispy.”Also known as “wispy.”

Cumulus-(a pile) Cumulus-(a pile) These clouds consist of rounded These clouds consist of rounded

individual cloud masses.individual cloud masses. They normally have a flat base and They normally have a flat base and

the appearance of towers and often the appearance of towers and often have a cauliflower structure.have a cauliflower structure.

Stratus-(a layer) Stratus-(a layer) Clouds are best described as sheets Clouds are best described as sheets

or layers that cover the sky.or layers that cover the sky.

High CloudsHigh Clouds

Cirrus, cirrostratus. cirrocumulus Cirrus, cirrostratus. cirrocumulus These clouds are not considered These clouds are not considered

precipitation makers.precipitation makers. May warn of approaching stormy May warn of approaching stormy

weather.weather.

Middle CloudsMiddle Clouds

Clouds that appear in the middle Clouds that appear in the middle range from about 2000-6000 meters.range from about 2000-6000 meters. Altocumulus and altostratus Altocumulus and altostratus

Low CloudsLow Clouds

Stratus, stratocumulus, and Stratus, stratocumulus, and nimbostratus.nimbostratus. The stratus clouds are like a uniform, a fog The stratus clouds are like a uniform, a fog

like layer of clouds that frequently cover like layer of clouds that frequently cover much of the sky.much of the sky.

““Nimbus” means “rainy cloud” and Nimbus” means “rainy cloud” and “stratus” means “to cover with a layer.”“stratus” means “to cover with a layer.” These clouds are known as precipitation These clouds are known as precipitation

makers.makers.

FogFog

Physically there is not difference between Physically there is not difference between a fog and a cloud but their appearance a fog and a cloud but their appearance and structure are the same.and structure are the same.

Their difference is the method and place of Their difference is the method and place of formation.formation.

Most fogs are the result of radiation Most fogs are the result of radiation cooling or the movement of air over a cold cooling or the movement of air over a cold surface.surface.

Fog is defined as a cloud with its base at Fog is defined as a cloud with its base at or very near the ground.or very near the ground.

How Precipitation FormsHow Precipitation Forms

Cloud droplets are very tiny, averaging Cloud droplets are very tiny, averaging less than 20 micrometers in diameter.less than 20 micrometers in diameter.

Because of their small size, the rate at Because of their small size, the rate at which cloud droplets fall is incredibly which cloud droplets fall is incredibly slow.slow.

For precipitation to form, cloud For precipitation to form, cloud droplets must grow in volume by droplets must grow in volume by roughly one million times.roughly one million times.

Cold Cloud PrecipitationCold Cloud Precipitation

The Bergeron process- a theory that relates the The Bergeron process- a theory that relates the formation of precipitation to super cooled clouds, formation of precipitation to super cooled clouds, freezing nuclei, and the different levels of ice and freezing nuclei, and the different levels of ice and liquid water.liquid water.

Supercooled- the condition of water droplets that Supercooled- the condition of water droplets that remain the liquid state at temperatures well remain the liquid state at temperatures well below 0 degrees Celsius below 0 degrees Celsius

Supersaturated- the condition of air that is more Supersaturated- the condition of air that is more highly concentrated than is normally possible highly concentrated than is normally possible under given temperature and pressure under given temperature and pressure conditions; when describing humidity it refers to a conditions; when describing humidity it refers to a relative humidity that is greater than 100 relative humidity that is greater than 100 percent.percent.

Forms of PrecipitationForms of Precipitation The type of precipitation that The type of precipitation that

reaches Earth’s surface depends on reaches Earth’s surface depends on the temperature profile in the lowest the temperature profile in the lowest few kilometers of the atmosphere.few kilometers of the atmosphere.