What causes the weather?

Under pressure

If you took an average slice of the atmosphere from the north pole to the equator, it would look like the one below.

• There is low pressure where air rises - at the Equator and along the polar front.
• There is high pressure where air sinks - near the subtropics and at the poles.

As you can see from the diagram, air flows from high to low pressure. This picture helps explain many aspects of the climate of the tropics, subtropics, midlatitudes, and poles. (You can learn more about this here.) To understand the day-to-day weather, though, we need to look at how the areas of high and low pressure move around.

Next page   -> under pressure, continued

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