Chapter 23 Section 2 Chapter 23 Section 2 Review Page 586 #‘s 1-6Review Page 586 #‘s 1-6

“Clouds and Fog”“Clouds and Fog”

1. Describe the 1. Describe the conditions that are conditions that are necessary for clouds to necessary for clouds to form.form.

• You need particulates (dust, You need particulates (dust, pollen, etc.) with water vapor pollen, etc.) with water vapor and a temperature below the and a temperature below the dew point so that the air is dew point so that the air is saturated and clouds can form.saturated and clouds can form.

Cloud FormationCloud Formation

2. Explain the four 2. Explain the four processes of cooling processes of cooling that can lead to cloud that can lead to cloud formation.formation.

• Adiabatic cooling: rising and expansion Adiabatic cooling: rising and expansion of an air massof an air mass

• Mixing: mixing of moist air with another Mixing: mixing of moist air with another air mass of different temperatureair mass of different temperature

• Lifting: forced upward movement of air Lifting: forced upward movement of air as it moves up a mountainas it moves up a mountain

• Advective cooling: an air mass moving Advective cooling: an air mass moving over a cooler surface (land or water)over a cooler surface (land or water)

Adiabatic Adiabatic coolingcooling

Lifting air masses

Advective cooling in Advective cooling in Draper/SandyDraper/Sandy

3. Compare cirrus, 3. Compare cirrus, cumulus, and stratus cumulus, and stratus clouds.clouds.

• Cirrus: Cirrus: wispy, high-altitude wispy, high-altitude clouds composed of ice crystalsclouds composed of ice crystals

• Cumulus: Cumulus: puffy, vertically puffy, vertically growing clouds, usually growing clouds, usually associated with fair weatherassociated with fair weather

• StratusStratus: : layered and form when layered and form when warm moist air lies above a layer of warm moist air lies above a layer of cooler aircooler air

4. 4. Compare clouds with fog.Compare clouds with fog.

•Both form as a result of condensation of water vapor in the air

•Fog occurs near the surface of Earth

•Clouds occur at higher altitudes

CLOUDCLOUDS S

FOGFOG

5. Describe four ways in 5. Describe four ways in which fog can form.which fog can form.

• Radiation fog occurs as a result Radiation fog occurs as a result of the nightly cooling when a of the nightly cooling when a layer of air is in contact with the layer of air is in contact with the cold groundcold ground

• Advection fog occurs when Advection fog occurs when warm, moist air moves across a warm, moist air moves across a cold surface, like when moist cold surface, like when moist ocean air flows over landocean air flows over land

Radiation FogRadiation Fog

Advection FogAdvection Fog

5. Describe four ways in 5. Describe four ways in which fog can form. which fog can form. (continued)(continued)

• Upland fog forms when moist air Upland fog forms when moist air rises over a sloperises over a slope

• Steam fog forms where cool air Steam fog forms where cool air moves over a warm body of moves over a warm body of waterwater

Upland fogUpland fog Steam fog over California beach

6. Explain why air expands 6. Explain why air expands when it rises.when it rises.

• When air rises it enters an area When air rises it enters an area of lower pressure. The lower air of lower pressure. The lower air pressure allows the air pressure allows the air molecules to move farther apart molecules to move farther apart (expand).(expand).

Rising, Expanding AirRising, Expanding Air

The End…..(what is it?)The End…..(what is it?)

An Aurora…..