5. Atmospheric Heat and Pressure

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

Yes, warm air rises and cold air sinks, because of the influence of temperature on density (remember that an increase in temperature results in an increase in volume, thereby reducing the density).

Convection in the atmosphere is driven by the influence of air temperature on air density.

How will convection affect air pressure at sea level?

Examine the diagram below showing the atmosphere (in light blue) above the waters of the ocean (in dark blue) to understand this important concept!

As shown in the diagram at the left: 

• Masses of cold air in the  atmosphere sink, causing  air in the lower atmosphere to be compressed

• Whereas, masses of warm air rise, decompressing the air below

• Regions of compressed air, below cold, sinking air produce high pressure systems in the lower atmosphere

• Regions of decompressed air, below warm, rising air produce low pressure systems in the lower atmosphere

What happens to the atmospheric pressure below masses of warm, rising air?

a) The air below is compressed, producing high pressure.
b) The air below is decompressed, producing low pressure.
c) None of the above, producing no pressure.
d) Both a and b, producing alternating pressure systems.