18.3 – Cloud Types and Precipitation

Do Now How are clouds classified?

Do Now How are clouds classified? On the basis of their form and height.

Key Words Classified Meteorology

Vocab Words Cirrus Cumulus Stratus Bergeron Process Collision- Coalescence Process Vocab Words

Types of Clouds Nimbo – means rain/precipitation Basic forms of clouds Cirrus Cumulus Stratus Three heights of clouds High Cirro- Middle Alto- Low Strato- Nimbo – means rain/precipitation

Cirrus Clouds Cirrus – curl of hair. They are clouds that are high, white, and thin.

Types of High Clouds Cirrus clouds are high, white, and thin. Cirrostratus clouds are flat layers of clouds. Cirrocumulus clouds consist of fluffy masses.

Identify the Cloud

Cumulus Clouds Cumulus – a pile Usually rounded like cotton balls. Cumulus are clouds that consist of rounded individual cloud masses.

Types of Middle Clouds Altocumulus clouds are composed of rounded masses that differ from cirrocumulus clouds in that altocumulus clouds are larger and denser. Altostratus clouds create a uniform white to gray sheet covering the sky with the sun or moon visible as a bright spot.

Identify the Cloud

Stratus Clouds Stratus – a layer Stratus clouds are clouds best described as sheets or layers that cover much or all of the sky.

Types of Low Clouds Stratus clouds are best described as sheets or layers that cover much or all of the sky. Stratocumulus clouds have a scalloped bottom that appears as long parallel rolls or broken rounded patches. Nimbostratus clouds are the main precipitation makers.

Identify the Cloud

Nimbus- Clouds Nimbus = rain These clouds are saturated and will bring precipitation. Nimbostratus Cumulonimbus (thunderheads)

Identify the Cloud

Clouds of Vertical Development Some clouds do not fit into any one of the three height categories mentioned. Such clouds have their bases in the low height range but often extend upward into the middle or high altitudes.

Fog Fog is defined as a cloud with its base at or very near the ground. Fog Caused by Cooling As the air cools, it becomes denser and drains into low areas such as river valleys, where thick fog accumulations may occur. Fog Caused by Evaporation When cool air moves over warm water, enough moisture may evaporate from the water surface to produce saturation.

Formation of Precipitation For precipitation to form, cloud droplets must grow in volume by roughly one million times. The Bergeron Process is when ice crystals grow in a cloud and continue to grow till the are large enough to fall. (Cold Cloud Precipitation) Collision-Coalescence Process is when warm clouds have saturation that leads to the formation of rain. (Warm Cloud Precipitation)

Forms of Precipitation The type of precipitation that reaches Earth's surface depends on the temperature profile in the lowest few kilometers of the atmosphere. Drizzle – Very tiny water droplets that fall slowly Dew – Moisture that condenses on the grass and ground Frost – Freezing water vapor that condenses on the grass and ground Rain – Larger water droplets that fall out of clouds Snow – Freezing water vapor inside clouds makes this Sleet – Rain that freezes on the way down Glaze – Raindrops falling on frozen ground form this Hail – Raindrops that get caught in updrafts, freeze, and build up layers of ice to form round pellets.

Group Challenge Question Copy Figure 12 on pages 518-519 and on the back describe the clouds and how you could identify them in the sky.