22.3Atmospheric Circulation

It all starts with unequal heating of Earth that cause differences in pressure

• Warm air is less dense, rises and creates LOW pressure

• Cold air is more dense, sinks and creates HIGH pressure.

• Air flows from poles (H) to equator (L)

In a high pressure area, air will (rise, sink) because the air is (less, more) dense.

This is because the air is (cold, warm)

and (rises, sinks). Therefore, clouds CANNOT form.

In a low pressure area, air will (rise, sink) because the air is (less, more) dense.

This is because the air is (cold, warm)

and (rises, sinks). Therefore, clouds are

LIKELY to form.

Coriolis Effect

• Moving objects follow a curved path due to Earth’s rotation.

• Deflected right in northern hemisphere (Clockwise)

• Deflected left in southern hemishphere (Counterclockwise)

Global Winds• Wind flows from poles to

equator in convective cells.• Each cell correlates to a

wind belt that forms wind that flows one way. (prevailing wind)

• Wind is named for the direction it come from.

• Doldrums – form at equator where the warm air moves upward and there is little wind.

• Horse Latitudes –form at 30 degrees N and S where the air decends and there is little wind

Jet Stream

Narrow band of strong wind that blows in the upper troposphere

Local Wind

Land Breeze – cool wind moving from land to water at night

Sea Breeze – cool wind moving from water to land in afternoon H

H

L

L

Warm Land

Cool Water

Cool LandWarm Water

Valley Breeze – warm air from the valley moves upslope during day

• Mountain Breeze

Mountain Breeze – cool air descends from mountain peak at night