Earth Science

Atmospheric Processes

Global Wind Belts

Study Tip
Pressure, like heat, moves from areas of high concentrations to areas of low concentrations.

Global Wind Belts

  • The wind on our planet blows in global wind belts that encircle the Earth.
  • The global wind belts are enormous, and their streams are relatively steady.
Study Tip
Pressure, like heat, moves from areas of high concentrations to areas of low concentrations.
  • The locations of the wind belts correlate with the atmospheric circulation cells. There are six circulation cells in the atmosphere, and three on each hemisphere.
  • In these circulation cells, the air moves from a high pressure to a low pressure, creating the global wind belts.
  • The high and low pressure regions created by the six atmospheric circulation cells determine the amount of precipitation a region.
  • Rainfall and storms are common in low pressure regions due to the rising air.
  • Evaporation occurs in dry areas when the air sinks in high pressure areas.
  • Local winds result from air moving between small low and high pressure systems.

The Global Winds

  • Trade Winds (Hadley Cell)
  • Normally, the air should move from the north to the south, but it is deflected by the Coriolis Effect, or the impact on the Earth due to its rotation. The Hadley Cell blows from the northeast to the southwest.
  • This belt is often referred as the trade winds, as they were great for sailing ships in.
  • Westerlies (Ferrel Cell)
  • The air should move from the south to the north, but the winds actually blow from the southwest.
  • This belt is the westerly winds or westerlies
  • Polar Easterlies (Polar Cell)
  • The wind from the polar easterlies travel from the northeast.
The major wind BELTS
The major wind belts and their directions are organized by latitude.

Earth Science

Polar Fronts and Jet Streams

Polar Fronts and Jet Streams
The air in the atmosphere circulates, which can create jet streams and polar fronts.
Concept Check
  • How do convection cells influence the weather?
  • What is the weather like where two cells meet?
  • What are the different winds and what directions do they blow?
  • Explain how jet streams are created and where they are found.