What mechanism causes air to rise on a regional scale?

Answer 1

• Convective uplift: Convection refers to upward and downward motions

of air caused by differences in air temperature (and therefore, differences

in air density).As the Sun warms the ground, the ground warms the air

immediately above it. Cooler, denser air from above sinks and forces the

warmer, less-dense air at the ground to rise.The ascending warm air

expands and cools and eventually sinks back to the ground, completing the

convective circulation.

• Orographic uplift: Orographic refers to mountains.When the wind

encounters a mountain range, the mountain range acts as a barrier, and

forces the air upward.

• Frontal wedging: A front is a narrow zone of transition between air

masses that contrast in temperature and/or humidity.When a cold air

mass meets a warm air mass, the more dense cold air wedges or forces

its way beneath the less dense warm air along a cold front.

• Convergence: When winds blowing from different directions meet headto-

head, or converge, they have nowhere to go but up.