Air rises at the equator and sinks at the poles The equator receives more direct sun than other areas so the air is less dense and rises to create low pressure. This warm air flows to the poles then cools and sinks creating high pressure. The air is constantly in motion with this pattern called convection.

Pressure Belts Pressure Belts are found at every 30degrees on the globe. Air travels in the large circular patterns called convection cells. These cells are separated by areas of high and low pressure called pressure belts.

Coriolis Effect Because the earth is rotating and curves, winds do not travel in straight lines. The curving of the wind due to the Earth’s rotation and curve is called the Coriolis effect The Coriolis effect causes winds to curve instead of flowing in straight lines.

Polar Easterlies Wind belts that extend from the poles to about 60degrees North and South In the northern Hemisphere the polar easterlies carry cold artic air over the united states producing snow and freezing weather.

Westerlies The wind belts found between 30 and 60 degrees latitude in both hemispheres are called Westerlies These flow TO the poles from west to east. These bring moist air to the United States and create rain and snow.

Trade Winds Winds that blow from 30 degrees latitude to the equator are called trade winds. The Coriolis effect causes trade winds to curve to the west in both hemispheres. These winds used to help carry ships from Europe to the America’s to help with trading goods, that’s why they are called trade winds.

Doldrums The area where the trade winds meet are called the doldrums. This area has very little wind because the warm rising air creates a large area of low pressure.

Horse Latitudes These are at 30 degrees North and South The warm air that rose from the equator is now sinking in this area and creating an area of high pressure. Winds in this area are very weak. Most of the worlds deserts are located in this area because the sinking air is very dry.