GEOG 2050 Chapter : Geography Unit 8 9
Document Summary
Air pressure & winds: high pressure clear blue skies, clear weather, cold air, low pressure cloudy skies, bad weather, warm air. Switch in pressure leads to switch in weather: prevailing winds wind that will always blow in the same direction, pressure force/unit area. Surface pressure, the standard sea level air pressure = 1013. 14. 7 lb/in2: below 980 mb = low pressure, big weather change, barometer. Pressure lines on surface weather chart are called isobars: aneroid barometer uses partial vacuum instrument to measure pressure. Standard sea level pressure is 760 mm (29. 92 inches) The amount of gravity, as you move away from the surface & the weight of the air above you. Pressure continuously decreases as you go up away from the surface: ultimate source of energy for wind is the sun. Uneven heating by latitudes results in movement of heat towards cooler regions: air movement is also influenced by the earth"s rotation-coriolis force earth"s in spinning. xi.
