ATMOSPHERIC PRESSURE zl657tCCudw

Atmospheric Pressure Force or weight of air pushing down on any given area

Pressure Top of atmosphere Sea Level More Molecules High Pressure Less Molecules Low Pressure

Measuring Pressure Instrument -Barometer Mercury Aneroid

Units – Standard Sea Level Pressure: inches of Hg or mb Isobars – lines of equal pressure on a weather map Millibars (mb) or Inches of Hg (mercury) ESRT Page 13

13 ESRT Page

30.10 inches of Hg = ______ mb

A. Pressure Relationships Temperature Top of atmosphere Sea level COLD HOT Molecules slow down Weigh more High density Molecules move fast and far apart Weigh less Less density HIGH PRESSURE LOW PRESSURE

Moisture Increasing water vapor makes air Nitrogen weighs more than the water vapor that replaces it Therefore, moist air is lower pressure than dry air lighter

Altitude/Elevation Top of Atmosphere Sea Level HIGH PRESSURE LOW PRESSURE More molecules Less molecules

Therefore……. Air with most pressure is ____________ Air with least pressure is ___________ Cold and dry Warm and moist

In Graph Form Pressure vs. Temperature What kind of relationship? Indirect LowHigh Low High Pressure Temperature

In Graph Form Pressure vs. Moisture What kind of relationship? Indirect LowHigh Low High Pressure Moisture

In Graph Form Pressure vs. Elevation What kind of relationship? Indirect LowHigh Low High Pressure Elevation

Go to page mb = inches of Hg mb = inches of Hg mb = inches of Hg inches of Hg = mb inches of Hg = mb inches of Hg = mb