Unformatted text preview: Measured with a barometer • Average pressure at sea level can be expressed in different ways: 1 kilogram/cm2=15 pounds/in2= 101,320 Pa (pascals)=76 cm Hg (mercury)=29.92 in Hg=1013.2 mb (millibars) Values are important because they provide the cutoff measurements used to define low and high pressure cells. • Atmospheric pressure at a single location varies slightly from day to day. • Differences in atmospheric pressure circulate the air, and create our winds • Helps to cycle water from oceans to the landmasses • Is an important factor in driving the world’s ocean currents. • • Air Pressure- mass of air above a given level. • Atmospheric pressure always decreases with increasing height. Air molecules exert a force on all surfaces with which they are in contact and the amount of that force exerted per unit of surface area is pressure....
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- Spring '10