1. Unit 4-2: Clouds

2. Fog – A cloud on the ground When the air at the surface becomes cooled below the dew point, water vapor condenses. When the air at the surface becomes cooled below the dew point, water vapor condenses. Tiny droplets of water adhere to condensation nuclei and fall incredibly slowly towards the ground. Tiny droplets of water adhere to condensation nuclei and fall incredibly slowly towards the ground. Light air movements keep them aloft. Light air movements keep them aloft.

3. Radiation Fog Also known as Ground Fog. Also known as Ground Fog. Forms when air above the surface cools below the dew point and condensation forms. Forms when air above the surface cools below the dew point and condensation forms. Found near humid valleys near rivers and lakes. Found near humid valleys near rivers and lakes. Usually “burn away” as the morning sun heats the ground and low hanging air. Usually “burn away” as the morning sun heats the ground and low hanging air.

4. Advection Fog Forms when warm moist air moves over a cool surface. Forms when warm moist air moves over a cool surface. Happens in the northern United States and Southern Canada when warm moist southerly winds move over snow covered ground, Happens in the northern United States and Southern Canada when warm moist southerly winds move over snow covered ground, Or, the warm moist wind moves over water. Or, the warm moist wind moves over water.

5. Advection Fog

6. The Origin of Clouds Clouds form in the upper atmosphere between 500m and 13,000m. Clouds form in the upper atmosphere between 500m and 13,000m. If the clouds form due to horizontal, or side to side, air movement, then the clouds form in layers. If the clouds form due to horizontal, or side to side, air movement, then the clouds form in layers. Called Stratiform clouds. Called Stratiform clouds. If the clouds form due to vertical, or up and down, air movement, then the clouds form upwards. If the clouds form due to vertical, or up and down, air movement, then the clouds form upwards. Called Cumuliform clouds. Called Cumuliform clouds.

8. What do these cloud names mean? Cirrus – Thin, feathery, tufted. Form very high and are made entirely of ice crystals. Cirrus – Thin, feathery, tufted. Form very high and are made entirely of ice crystals. Stratus – Low sheets or layers of cloud. Stratus – Low sheets or layers of cloud. Cumulus – Formed by vertically rising air, piled in thick, fleecy masses. Cumulus – Formed by vertically rising air, piled in thick, fleecy masses. Alto – High height cloud formation. Alto – High height cloud formation. Nimbus – High water content, usually means rain. Nimbus – High water content, usually means rain.

9. What type of cloud is this? Cirrus

10. What type of cloud is this? Cirrocumulus Cirrocumulus

11. What type of cloud is this? Stratus Stratus

12. What type of cloud is this? Cumulus Cumulus

13. What type of cloud is this? Cumulonimbus Cumulonimbus