6. Global Atmospheric Pressure

The variations in atmospheric heat produce variations in rising and sinking air masses, and hence changes in atmospheric pressure.

Examine the map below showing the global distribution of atmospheric pressure measured at sea level in millibars.

The regions colored in yellow indicate low atmospheric pressure at the equator below areas of warm, rising air.

The regions colored in magenta and red indicate high atmospheric pressure below cold, sinking masses of air (centered at 30^o North and South of the equator).

Expedition Menu

1. Introduction
2. Ocean Temperature
3. Circulation
4. Atmospheric Heat
5. Heat and Pressure
6. Atmospheric Pressure
7. Air Pressure and Wind
8. Wind Directions
9. Global Wind Patterns
10. Measuring Circulation

• The regions of very low atmospheric pressure centered at 60^o north and south of the equator, represent regions where "warm" air from the temperate regions rises above cold air masses spreading away from the high pressure systems of the polar regions.

  

• Once again regions below rising air form areas of low atmospheric pressure at sea level.