GEOG220 Lecture Notes - Lecture 3: Compressible Flow, Atmospheric Pressure

• School: University of Delaware
• Department: Geography
• Course: GEOG220
• Professor: Leathers Dan

Document Summary

Atmospheric pressure - the force exerted by the atmosphere on some specific area. At the earth"s surface 1m^3 of the atmosphere has a mass of about 1 kg. Atmospheric pressure at any height in the atmosphere is dependent on the total mass of the atmosphere in a column above that point (shown by f=ma) The atmosphere is a compressible fluid, thus density = mass/volume (d=m/v) So, pressure and density decrease rapidly with height. Surface pressure is constantly changing, thus there has to be some way that molecules are moving into or out of the column of pressure. Pressure differences are the reason that we have winds. Barometer introduced that concept that air pressure is always changing. A glass tube of mercury would either fill or empty depending on the air pressure outside. Normal range of sea level pressure = 960-1060 (mb) absolute average sea level pressure = 1013. 25 mb.