Global Winds and Local Winds

Wind- movement of air caused by differences in air pressure Air rises at the equator and sinks at the poles The equator receives more direct sunlight creating less dense, warm, rising air toward the poles leaving an area of low pressure.

At the poles, air is colder so it sinks toward the equator leaving an area of high pressure.

Why does sinking air cause areas of high pressure?

Sinking air causes areas of high pressure because sinking air presses down on the air beneath it.

Pressure Belts are found every 30 degrees Pressure belts- bands of high pressure and low pressure found every 30 ° latitude The uneven heating of the Earth produces pressure belts. These belts occur at about every 30 ° of latitude.

Coriolis effect curving of the path of winds and ocean currents due to Earth’s rotation

Global Winds

Produced from the combination of convection cells found at every 30 ° latitude and the Coriolis effect.

Global winds

Polar easterlies Westerlies Trade winds Doldrums Horse latitudes

Polar easterlies

 Cold, sinking air that blow from east to west from the poles to 60 ° latitude - Can carry cold arctic air over the United States producing snow and freezing weather

Westerlies

 Winds that blow from west to east toward the poles

Trade winds

 Early traders used the trade winds to sail from Europe to the Americas  Winds that blow toward the equator

Doldrums

 Means “dull” or “sluggish” - Area near the equator where trade winds meet from the Northern and Southern hemispheres

Jet streams

Narrow belts of high-speed winds that blow in the upper troposphere

Local winds

Sea breeze Land breeze Mountain breeze Valley breeze

Sea and Land Breezes

Mountain Breezes and Valley Breezes During the day, the sun warms the air along the mountain slopes. This warm air rises up the mountain slopes, creating a valley breeze At night time, the air along the mountain slopes cools. This cool air moves down the slopes into the valley, producing a mountain breeze.

Why does the wind tend to blow down from mountains at night?

At night, the air along the mountain slopes cools. This cool air moves down the slopes into the valley and produces a mountain breeze.