WINDS RELATED TO GLOBAL AIR CIRCULATION

What are the Tropical Easterlies (Trade Winds)?

Winds that blow from the Subtropical High Pressure Belt (30°) toward the Equatorial Low Pressure Belt (ITCZ). Found between 5°–30° N and S. Called the NE Trade Winds in the Northern Hemisphere and SE Trade Winds in the Southern Hemisphere.

What are the Westerlies?

Winds that blow from the Subtropical High Pressure Belt (30°) toward the Sub-Polar Low Pressure Belt (60°). Found between 30°–60° N and S. Called the NW Westerlies in the Southern Hemisphere and SW Westerlies in the Northern Hemisphere.

What are the Polar Easterlies?

Winds that blow from the Polar High Pressure Belt (90°) toward the Sub-Polar Low (60°). Found between 60°–90° N and S. Called Polar SE in the Southern Hemisphere and Polar NE in the Northern Hemisphere.

Why are these winds called "secondary air circulation"?

Because they are not the primary global convection cells — they are the surface winds that result from pressure differences between the major world pressure belts.

What weather do the Trade Winds bring?

Fine, sunny, dry weather at 30° (horse latitudes). As they move toward the equator and pick up moisture from warm oceans, they can bring tropical rainfall.

What weather do the Westerlies bring to South Africa?

The Westerlies bring mid-latitude cyclones (cold fronts) and associated rainfall to the southern tip of South Africa, especially the Western Cape in winter.