GEOG 101 Lecture Notes - Lecture 14: Stellar Atmosphere, Stratopause, Thermosphere
Document Summary
The amount of force exerted by the air on the surface below: measured with a barometer. Air pressure always decreases with increasing height: it is commonly measured in hectopascals (hpa) or millibars (mb, 1 hpa = 1 mb, 10 hpa = 1 kpa (kilopascal) Average air pressure at the surface is 1013 hpa: low pressure = below 1005 hpa, lower the pressure the more inclement/bad the weather, high pressure = 1020 hpa, often higher the pressure the better the weather. In the lowest levels of the atmosphere, air pressure most rapidly decreases with increasing height. Air density also decreases with increasing height because gravity pulls air molecules toward the surfaces. The atmosphere may be classified into 4 layers by observing its vertical temperature profile. The bottom most layer; it is where all weather occurs. The thinnest layer (about 11 km thick) It is primarily heated by the earth"s surface. Its upper boundary is called the troposphere.
