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Wind And Air Pressure. Chapter - 19. weight of all the air above you 14.7 pounds per square inch at sea level pascal’s principle equal force in all directions pressure decreases as you increase in elevation 50% for each 5 km. Measuring it Tools Barometer two types Mercury Aneroid.
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Wind And Air Pressure Chapter - 19
weight of all the air above you 14.7 pounds per square inch at sea level pascal’s principle equal force in all directions pressure decreases as you increase in elevation 50% for each 5 km Measuring it Tools Barometer two types Mercury Aneroid Air Pressure
Units of Air Pressure inches or millimeters of mercury 760 millimeters @ sealevel About 30 inches @ sealevel Millibars used by weather people 1013 millibars @ sealevel 835 millibars @ Denver Pressure maps Isobars lines of equal pressure move in to circles pressure rise as you move in = high pressure decreases as you move in = low the change in pressure over a distance is the pressure gradient
Elevation change Change in temperature Warmer molecules farther apart decreases pressure change in humidity high humidity = lower pressure air is mostly nitrogen and oxygen which are heavier molecules than water Why does Pressure change
Low pressure warmer, moister, with higher probability of precipitation rising air high pressure cooler, drier, with low probability of precipitation. sinking air Weather Associations
How form “Things will flow from high to low and winds are named from where they came” high to low pressure greater the diff in pressure = stronger winds pressure differences caused by uneven heating land and water diff in temp larger = stronger Daytime sea breaze Night land breaze Winds
how measured direction wind vane speed anemometer
#1 high to low local winds global use this plus the coreolis effect #2 coreolis effect launch rocket from pole to hit Kansas 1 hour flight planet rotates 15 degrees rocket hits in nevada turns the winds to the right in the north left in the south greatest near the poles more for faster objects cause air to flow clockwise out of a high counter clockwise into a low southern hemisphere reversed Direction of flow
#3 friction more equals less deflection as you increase in height the friction goes down #4 Earth’s rotation If no rotation air would flow from equator to the poles Causes the three celled model Each hemisphere has three cells in it 0-30, 30-60, 60-90 degrees north move right , south left