|
Weather Glossary
Atmospheric pressure The amount of force exerted over a surface area, caused by the weight of air molecules above it. As elevation increases, fewer air molecules are present. Therefore, atmospheric pressure always decreases with increasing height. A column of air in cross section, measured from sea level to the top of the atmosphere, would weigh approximately 14.7 pounds per square inch (psi). The standard value for atmospheric pressure at sea level is: 29.92 inches or 760mm of mercury; 1013.25 millibars (Mb) or 101,325 pascals (pa).
|
