A WINDY WORLD

How streams of air are defined as they traverse the globe

6 MID-LATITUDE CELL

The airflow in this cell moves in the reverse direction to that in the Hadley cells. Air moves towards the poles near Earth’s surface and towards the equator at higher altitudes.

8 INTERTROPICAL CONVERGENCE ZONE

About five degrees above and below the equator, trade winds move southwest, colliding with trade winds moving northwest. The air moves upwards, resulting in little surface wind here.

7 POLAR CELL

Polar cells are smaller and weaker than other cells. Air sinks when reaching the highest latitudes and travels towards lower latitudes when it reaches Earth’s surface.

1 POLAR EASTERLIES

These dry winds move from cold, high-pressure areas at the north and south pole to low-pressure areas. They blow from the east.

2 POLAR FRONT

The region between tropical air and polar air is called the polar front.

3 WESTERLIES

In the middle latitudes – between 30 and 60 degrees – westerlies are the prevailing winds from the west. They often produce anticyclones.

4 HADLEY CELLS

These cells make up the global tropical atmospheric circulation. Air rises near the equator and moves towards the poles.

5 TRADE WINDS

These easterly winds blow around Earth near the equator. Trade winds produce ocean currents, used by early sailing ships and modern commercial ships for quicker journeys.

9 HORSE LATITUDES

The regions of calm air where westerlies and trade winds meet in both the Northern and Southern Hemisphere are called horse latitudes.