MECHANISMS that cause air to rise

Learning goal: Describe processes that lift air to aid in the formation of clouds.

1. Convective uplift: During the day the ground becomes very hot. The hot air is less dense and it rises.

2. Orographic Lifting: air is forced to rise when it meets a mountain.

3. CONVERGENCE:- Late afternoon thunderstorms in Florida are caused by convergence of sea breezes from both the Atlantic Ocean and the Gulf of Mexico.

Air over the land is hot

AIR MASSES• What is an air mass?

An air mass is an immense body of air that has the same temperature and or humidity at any given altitude.

How are air masses classified?

• They are classified by their temperature, humidity and according to the surface over which they form.

• Continental: dry air masses that form over land.• Maritime: humid air masses that form over the

ocean.• Polar: cold air masses that form at high

latitudes.• Tropical: warm air masses that form at low

latitudes

4. Frontal Wedging: when a cold air mass meets a warm air mass, the more cold dense air wedges (forces) its way beneath the less dense warm air.

Homework• Prentice Hall; page 563• Questions 4, 5, 7, 8, 9 and 10