Clouds and Fog Section 24.2

Cloud Formation Clouds result from the condensation of water vapor in the atmosphere Suspended particles of ice, slat, dust, etc, provide the surfaces necessary for the cloud-forming condensation. These particles are called condensation nuclei.

Adiabatic Temperature Changes Are changes in temperature that result from the expansion or compression of air For dry air, temperature of dry air decreases about 1°C for every 100 m For moist air it varies from 0.5°C to 0.7°C per 100m

Condensation Level When the air reaches a level where its temperature is lower than its dew point, the moisture in the air condenses to form a cloud

Forceful Lifting Air can be forced up quickly when it encounters a mountain range During storms, warm air is pushed above denser cooler air

Classification of Clouds Clouds are classified by their form and altitude Low clouds – up to 2000 m middle clouds -2000-6000 m high clouds – above 6000 m

Stratus clouds Sheetlike, layered clouds. These are the most extensive clouds in the sky. Little rain usually falls from these kinds of clouds Varieties: nimbostratus, altostruatus

Cumulus

Cumulus CLouds

Cirrus Clouds